Author Topic: Astronomy  (Read 74110 times)


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« on: April 09, 2009, 01:18:02 PM »


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Saturn & Moons
« Reply #1 on: April 21, 2009, 07:39:39 PM »


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Carina Nebula
« Reply #2 on: May 26, 2009, 07:41:25 AM »

Carina Nebula Panorama from Hubble
Credit: NASA, ESA, N. Smith (U. California, Berkeley) et al., and The Hubble Heritage Team (STScI/AURA)
Explanation: In one of the brightest parts of Milky Way lies a nebula where some of the oddest things occur. NGC 3372, known as the Great Nebula in Carina, is home to massive stars and changing nebulas. Eta Carinae, the most energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, but then faded dramatically. The Keyhole Nebula, visible left of center, houses several of the most massive stars known and has also changed its appearance. The entire Carina Nebula spans over 300 light years and lies about 7,500 light-years away in the constellation of Carina. Pictured above is the most detailed image of the Carina Nebula ever taken. The controlled color image is a composite of 48 high-resolution frames taken by the Hubble Space Telescope two years ago. Wide-field annotated and zoomable image versions are also available.


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Re: Astronomy
« Reply #3 on: May 29, 2009, 02:10:55 PM »

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New Solar Cycle Predictions
This plot of sunspot numbers shows the measured peak of the last solar cycle (Solar Cycle 23) in blue and the predicted peak of the next solar cycle (24) in red. Credit: NOAA/Space Weather Prediction Center.

by Tony Phillips

Boulder CO (SPX) May 28, 2009

An international panel of experts has released a new prediction for the next solar cycle, stating that Solar Cycle 24 will peak in May 2013 with a below-average number of sunspots. Led by the National Oceanic and Atmospheric Administration (NOAA) and sponsored by NASA, the panel includes a dozen members from nine different government and academic institutions.

Their forecast sets the stage for at least another year of mostly quiet conditions before solar activity resumes in earnest.

"If our prediction is correct, Solar Cycle 24 will have a peak sunspot number of 90, the lowest of any cycle since 1928 when Solar Cycle 16 peaked at 78," says panel chairman Doug Biesecker of the NOAA Space Weather Prediction Center, Boulder, Colo.

It is tempting to describe such a cycle as "weak" or "mild," but that could give the wrong impression. "Even a below-average cycle is capable of producing severe space weather," says Biesecker. "The great geomagnetic storm of 1859, for instance, occurred during a solar cycle of about the same size we're predicting for 2013."

The 1859 storm - named the "Carrington Event" after astronomer Richard Carrington who witnessed the instigating solar flare - electrified transmission cables, set fires in telegraph offices, and produced Northern Lights so bright that people could read newspapers by their red and green glow.

A recent report by the National Academy of Sciences found that if a similar storm occurred today, it could cause $1 to 2 trillion in damages to society's high-tech infrastructure and require four to ten years for complete recovery. For comparison, Hurricane Katrina caused $80 to 125 billion in damage.

The latest forecast revises a prediction issued in 2007, when a sharply divided panel believed solar minimum would come in March 2008 and would be followed by either a strong solar maximum in 2011 or a weak solar maximum in 2012. Competing models of the solar cycle produced different forecasts, and researchers were eager for the sun to reveal which was correct.

"It turns out that none of the models were really correct," says Dean Pesnell of the Goddard Space Flight Center, Greenbelt, Md. NASA's lead representative on the panel. "The sun is behaving in an unexpected and very interesting way."

Astronomers first noted the solar cycle in the mid-1800s. Graphs of sunspot numbers resemble a roller coaster, going up and down with an approximately 11-year period. Predicting the peaks and valleys has proven troublesome because cycles vary in length from 9 to 14 years. Some peaks are high, others low.

The valleys are usually brief, lasting only a couple of years, but sometimes they stretch much longer. In the 17th century, the sun plunged into a 70-year period of spotless quiet known as the Maunder Minimum that still baffles scientists.

Right now, the solar cycle is in a valley--the deepest of the past century. In 2008 and 2009, the sun set Space Age records for low sunspot counts, weak solar wind, and low solar irradiance. The sun has gone more than two years without a significant solar flare.

"In our professional careers, we've never seen anything quite like it," says Pesnell. "Solar minimum has lasted far beyond what we predicted in 2007."

In recent months, however, the sun has begun to show signs of life. Small sunspots and "proto-sunspots" are popping up with increasing frequency. Enormous currents of plasma on the sun's surface ("zonal flows") are gaining strength and slowly drifting toward the sun's equator.

Radio astronomers have detected a tiny but significant uptick in solar radio emissions. All these things are precursors of an awakening Solar Cycle 24 and form the basis for the panel's new, almost unanimous forecast.

According to the forecast, the sun should remain generally calm for at least another year. From a research point of view, that's good news because solar minimum has proven to be more interesting than anyone imagined. Low solar activity has a profound effect on Earth's atmosphere, allowing it to cool and contract. Space junk accumulates in Earth orbit because there is less aerodynamic drag.

The becalmed solar wind whips up fewer magnetic storms around Earth's poles. Cosmic rays that are normally pushed back by solar wind instead intrude on the near-Earth environment. There are other side-effects, too, that can be studied only so long as the sun remains quiet.

Meanwhile, the sun pays little heed to human committees. There could be more surprises, panelists acknowledge, and more revisions to the forecast.

"Go ahead and mark your calendar for May 2013," says Pesnell. "But use a pencil."


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Re: Astronomy
« Reply #4 on: May 30, 2009, 04:55:11 AM »


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Volcano Eruption as seen on the ISS
« Reply #5 on: June 22, 2009, 09:36:00 AM »

Sarychev Peak on Matua Island is one of the most active volcanoes in the Kuril Island chain, northeast of Japan. Astronauts took this photo of an eruption on June 12. The plume appears to be a combination of brown ash and white steam. The vigorously rising plume gives the steam a bubble-like appearance; the surrounding atmosphere has been shoved up by the shock wave of the eruption. Credit: NASA/ISS/Earth Observatory


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Re: Astronomy
« Reply #6 on: June 22, 2009, 02:37:12 PM »
BBG, Amazing photo!!  Curious, do they apply for a greenhouse gas permit before eruption or, like Communist China, is God excluded from Kyoto jurisdiction?


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Re: Astronomy
« Reply #7 on: June 22, 2009, 08:37:18 PM »
Doug, these emissions are all natural, which, by definition, means they must be good, at least judging by all the labels I see at the supermarket.


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Sauron's Sky?
« Reply #8 on: July 27, 2009, 05:32:18 AM »

NGC 1097: Spiral Galaxy with a Central Eye
Credit: NASA, JPL-Caltech, SINGS Team (SSC)
Explanation: What's happening at the center of spiral galaxy NGC 1097? No one is sure, but it likely involves a supermassive black hole. Matter falling in from a bar of stars and gas across the center is likely being heated by an extremely energetic region surrounding the central black hole. From afar, the entire central region appears in the above false-color infrared image as a mysterious eye. Near the left edge and seen in blue, a smaller companion galaxy is wrapped in the spectacular spiral arms of the large spiral, lit in pink by glowing dust. Currently about 40 thousand light-years from the larger galaxy's center, the gravity of the companion galaxy appears to be reshaping the larger galaxy as it is slowly being destroyed itself. NGC 1097 is located about 50 million light years away toward the constellation of the furnace (Fornax).


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Skipped Solar Cycle?
« Reply #9 on: August 01, 2009, 06:31:08 PM »
This abstract is pretty dense, and leads to the full piece that's even denser. Not sure either is worth wading through, though I do think it's important to note how small the data set for our star is and how it's failed to adhere to the model extrapolated from that small data set. As the sun is the source of the energy that warms the planet, one would think the global warming crowd would be inspired toward humility by pieces like this.

Some speculation that solar cycle 25 has already begun
Leif Svalgaard writes:

Some speculation that solar cycle 25 has already begun:

From a 2006 NASA News article - In red, David Hathaway's predictions for the next two solar cycles and, in pink, Mausumi Dikpati's prediction for cycle 24, and the expected "low" cycle 25.
Graph source: NASA News

This would be stunning, because it suggests that the sun has skipped a solar cycle (#24) . Researchers, three from the Harvard-Smithsonian Center for Astrophysics and the other from Marshall Space Flight Center-NASA, have published a paper that suggests this possibility.

Does a polar coronal hole’s flux emergence follow a Hale-like law?
A. Savcheva1, J.W. Cirtain2, E.E. DeLuca1, L. Golub1

Recent increases in spatial and temporal resolution for solar telescopes sensitive to EUV and X-ray radiation have revealed the prevalence of transient jet events in polar coronal holes. Using data collected by the X-Ray Telescope on Hinode, Savcheva et al. (2007) confirmed the observation, made first by the Soft X-ray Telescope on Yohkoh, that some jets exhibit a motion transverse to the jet outflow direction.

The velocity of this transverse motion is, on average, 20 kms−1. The direction of the transverse motion, in combination with the standard reconnection model for jet production (e.g. Shibata et al. 1992), reflects the magnetic polarity orientation of the ephemeral active region at the base of the jet. From this signature, we find that during the present minimum phase of the solar cycle the jet-base ephemeral active regions in the polar coronal holes had a preferred east-west direction, and that this direction reversed during the cycle’s progression through minimum.

In late 2006 and early 2007, the preferred direction was that of the active regions of the coming sunspot cycle (Cycle 24), but in late 2008 and early 2009 the preferred direction has been that of the active regions of sunspot cycle 25. These findings are consistent with the results of Wilson et al. (1988) that there is a high latitude expansion of the solar activity

Full paper here:


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Re: Astronomy
« Reply #10 on: August 03, 2009, 10:59:56 PM »

The diversity of your reading impresses.


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Cosmic Ray Cloud Connection
« Reply #11 on: August 08, 2009, 10:43:03 AM »
Not quite astronomy, but not far afield enough to inspire a new weather topic. Note that throughout this piece the process of cloud formation is said to be poorly understood, which again ought to inspire humility in circles where certainty is regularly trumpeted.

Do Clouds Come From Outer Space?

By Phil Berardelli
ScienceNOW Daily News
5 August 2009

Most of Earth's clouds get their start in deep space. That's the surprising conclusion from a team of researchers who argue that interstellar cosmic rays collide with water molecules in our atmosphere to form overcast skies.
As common as clouds are on Earth, the processes that produce them are not well understood. Scientists think particles of dust or pollen can serve as nuclei for water droplets, which in turn gather by the trillions into clouds. That would help explain how clouds form over urban areas: Fine particles called aerosols are emitted from the exhaust pipes of millions of vehicles and work their way into the atmosphere, where they are thought to attract water molecules. But it doesn't explain how clouds formed in preindustrial society--or how they form today over vast stretches of rainforest and ocean.

That's where cosmic rays come in. The idea goes like this: High-speed cosmic ray particles--protons and neutrons of still-mysterious origins that travel at nearly the speed of light--collide with water molecules in the atmosphere, stripping away electrons from those molecules and converting them into electrically charged ions. The ions then begin attracting other water molecules, which eventually form clouds.

The theory seems to hold water in the lab. In 2006, physicist Henrik Svensmark of the Technical University of Denmark in Copenhagen and colleagues produced aerosols artificially in an atmospheric chamber by bombarding water molecules with a particle beam. "More ions resulted in more aerosols," Svensmark says.

In the new study, Svensmark's team wanted to see if the idea also worked in the real world. The researchers focused on a phenomenon known as a Forbush decrease. Here, a massive storm on the sun's surface flings a superhot fog of particles, called a coronal mass ejection, past Earth, temporarily shielding our planet from cosmic rays. If cosmic rays really do contribute to cloud formation, Svensmark and colleagues hypothesized, then cloud cover should dip during Forbush decreases.

And indeed that's what Svensmark's team found. When the researchers examined cloud data collected by weather satellites over the past 22 years and compared them with 26 Forbush decreases, they discovered that, for the five strongest events, the water-droplet content of Earth's clouds decreased by an average of 7%. It's like bare patches forming in a field, says Svensmark, whose team reports its findings this month in Geophysical Research Letters. The cloud patterns eventually returned to normal, he says, but they took weeks to do so. "We're now convinced that aerosols are affected by the Forbush decrease," Svensmark says.

Geoscientist Jón Egill Kristjánsson of the University of Oslo, Norway, calls the findings "astonishing." He and other researchers have searched for years for relationships between Forbush decreases and cloud formation and have found nothing, or they have found significant relationships "only in very remote locations." If the data can be confirmed by other observations, he says, "Svensmark's new results would greatly strengthen the case for a cosmic ray-cloud connection."

Svensmark argues that the findings suggest a link between cosmic rays and climate change. Because clouds bring rain and reflect light from the sun, fewer clouds would mean a warmer Earth. But Kristjánsson isn't willing to go that far. Monitoring instruments "over the last 50 years or so show either no trend or a slightly upward trend" in cosmic rays hitting Earth, he notes. According to Svensmark's theory, that would mean either no increase in cloud formation or a slight increase--neither of which would warm the world.


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13 Images
« Reply #12 on: August 09, 2009, 07:54:06 AM »


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Sunspots & Space Weather
« Reply #13 on: August 22, 2009, 11:14:14 AM »
A nice site that reports on the sun/earth space weather environment.

ARE SUNSPOTS DISAPPEARING? Sunspots are made of magnetism. The "firmament" of a sunspot is not matter but rather a strong magnetic field that appears dark because it blocks the upflow of heat from the sun's fiery depths. Without magnetism, there would be no sunspots.

That's what makes the following graph a little troubling:

According to Bill Livingston and Matt Penn of the National Solar Observatory in Tucson, Arizona, sunspot magnetic fields are waning. The two respected solar astronomers have been measuring solar magnetism since 1992. Their technique is based on Zeeman splitting of infrared spectral lines emitted by iron atoms in the vicinity of sunspots. Extrapolating their data into the future suggests that sunspots could completely disappear within decades. That would be a bummer for

Don't count out sunspots just yet, however. While the data of Livingston and Penn are widely thought to be correct, far-reaching extrapolations may be premature. This type of measurement is relatively new, and the data reaches back less than 17 years. "Whether this is an omen of long-term sunspot decline, analogous to the Maunder Minimum, remains to be seen," they caution in a recent EOS article.


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Re: Astronomy
« Reply #14 on: September 02, 2009, 09:18:35 AM »
Nice shuttle launch pic:

Discovery's Rainbow
Credit: NASA, Ben Cooper (Launch Photography)
Explanation: Just one minute before midnight EDT, Friday, August 28, the Space Shuttle Discovery began a long arc into a cloudy sky. Following the launch, a bright and remarkably colorful trail was captured in this time exposure from the Banana River Viewing Site, looking east toward pad 39A at the Kennedy Space Center. On STS-128, Discovery docked with the International Space Station Sunday evening. The 13-day mission will exchange space station crew members and deliver more than 7 tons of supplies and equipment. Of course, the equipment includes the Combined Operational Load Bearing External Resistance Treadmill (COLBERT).


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Jupiter Impact
« Reply #15 on: September 08, 2009, 12:27:47 PM »
The image is animated at the NASA site, but doesn't appear to be working here.

Unexpected Impact on Jupiter
Credit: ALPO, Theo Ramakers
Explanation: Two months ago, something unexpected hit Jupiter. First discovered by an amateur astronomer Anthony Wesley on 2009 July 19, the impact was quickly confirmed and even imaged by the Hubble Space Telescope the very next day. Many of the world's telescopes then zoomed in on our Solar System's largest planet to see the result. Some of these images have been complied into the above animation. Over the course of the last month and a half, the above time-lapse sequence shows the dark spot -- first created when Jupiter was struck -- deforming and dissipating as Jupiter's clouds churned and Jupiter rotated. It is now thought that a small comet -- perhaps less than one kilometer across -- impacted Jupiter on or before 2009 July 19. Although initially expected to be visible for only a week, astronomers continue to track atmospheric remnants of the impact for new information about winds and currents in Jupiter's thick atmosphere.

« Last Edit: September 08, 2009, 12:29:40 PM by Body-by-Guinness »


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Milky Way Pic
« Reply #16 on: September 26, 2009, 07:15:42 AM »

Gigagalaxy Zoom: Milky Way
Credit: ESO / Serge Brunier, Frederic Tapissier - Copyright: Serge Brunier (TWAN)
Explanation: Our magnificent Milky Way Galaxy sprawls across this ambitious all-sky panorama. In fact, at 800 million pixels the full resolution mosaic strives to show all the stars the eye can see in planet Earth's night sky. Part of ESO's Gigagalaxy Zoom Project, the mosaicked images were recorded over several months of 2008 and 2009 at exceptional astronomical sites; the Atacama Desert in the southern hemisphere and the Canary Islands in the northern hemisphere. Also capturing bright planets and even a comet, the individual frames were stitched together and mapped into a single, flat, apparently seamless 360 by 180 degree view. The final result is oriented so the plane of our galaxy runs horizontally through the middle with the bulging Galactic Center at image center. Below and left of center are the Milky Way's satellite galaxies, the Magellanic Clouds.


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Solar Minimum's & Cosmic Rays
« Reply #17 on: October 03, 2009, 12:37:42 PM »
Cosmic Rays Hit Space Age High


September 29, 2009: Planning a trip to Mars? Take plenty of shielding. According to sensors on NASA's ACE (Advanced Composition Explorer) spacecraft, galactic cosmic rays have just hit a Space Age high.

"In 2009, cosmic ray intensities have increased 19% beyond anything we've seen in the past 50 years," says Richard Mewaldt of Caltech. "The increase is significant, and it could mean we need to re-think how much radiation shielding astronauts take with them on deep-space missions."

Above: Energetic iron nuclei counted by the Cosmic Ray Isotope Spectrometer on NASA's ACE spacecraft reveal that cosmic ray levels have jumped 19% above the previous Space Age high. [larger image]

The cause of the surge is solar minimum, a deep lull in solar activity that began around 2007 and continues today. Researchers have long known that cosmic rays go up when solar activity goes down. Right now solar activity is as weak as it has been in modern times, setting the stage for what Mewaldt calls "a perfect storm of cosmic rays."

"We're experiencing the deepest solar minimum in nearly a century," says Dean Pesnell of the Goddard Space Flight Center, "so it is no surprise that cosmic rays are at record levels for the Space Age."

Galactic cosmic rays come from outside the solar system. They are subatomic particles--mainly protons but also some heavy nuclei--accelerated to almost light speed by distant supernova explosions. Cosmic rays cause "air showers" of secondary particles when they hit Earth's atmosphere; they pose a health hazard to astronauts; and a single cosmic ray can disable a satellite if it hits an unlucky integrated circuit.

The sun's magnetic field is our first line of defense against these highly-charged, energetic particles. The entire solar system from Mercury to Pluto and beyond is surrounded by a bubble of magnetism called "the heliosphere." It springs from the sun's inner magnetic dynamo and is inflated to gargantuan proportions by the solar wind. When a cosmic ray tries to enter the solar system, it must fight through the heliosphere's outer layers; and if it makes it inside, there is a thicket of magnetic fields waiting to scatter and deflect the intruder.

Right: An artist's concept of the heliosphere, a magnetic bubble that partially protects the solar system from cosmic rays. [larger image]

"At times of low solar activity, this natural shielding is weakened, and more cosmic rays are able to reach the inner solar system," explains Pesnell.

Mewaldt lists three aspects of the current solar minimum that are combining to create the perfect storm:

1. The sun's magnetic field is weak. "There has been a sharp decline in the sun's interplanetary magnetic field down to 4 nT (nanoTesla) from typical values of 6 to 8 nT," he says. "This record-low interplanetary magnetic field undoubtedly contributes to the record-high cosmic ray fluxes." [data]

2. The solar wind is flagging. "Measurements by the Ulysses spacecraft show that solar wind pressure is at a 50-year low," he continues, "so the magnetic bubble that protects the solar system is not being inflated as much as usual." A smaller bubble gives cosmic rays a shorter-shot into the solar system. Once a cosmic ray enters the solar system, it must "swim upstream" against the solar wind. Solar wind speeds have dropped to very low levels in 2008 and 2009, making it easier than usual for a cosmic ray to proceed. [data]

3. The current sheet is flattening. Imagine the sun wearing a ballerina's skirt as wide as the entire solar system with an electrical current flowing along its wavy folds. It's real, and it's called the "heliospheric current sheet," a vast transition zone where the polarity of the sun's magnetic field changes from plus to minus. The current sheet is important because cosmic rays are guided by its folds. Lately, the current sheet has been flattening itself out, allowing cosmic rays more direct access to the inner solar system.

Right: The heliospheric current sheet is shaped like a ballerina's skirt. Image credit: J. R. Jokipii and B. Thomas, Astrophysical Journal 243, 1115, 1981.

"If the flattening continues, we could see cosmic ray fluxes jump all the way to 30% above previous Space Age highs," predicts Mewaldt. [data]

Earth is in no great peril. Our planet's atmosphere and magnetic field provide some defense against the extra cosmic rays. Indeed, we've experienced much worse in the past. Hundreds of years ago, cosmic ray fluxes were at least 200% to 300% higher than anything measured during the Space Age. Researchers know this because when cosmic rays hit the atmosphere, they produce an isotope of beryllium, 10Be, which is preserved in polar ice. By examining ice cores, it is possible to estimate cosmic ray fluxes more than a thousand years into the past. Even with the recent surge, cosmic rays today are much weaker than they have been at times in the past millennium. [data]

"The space era has so far experienced a time of relatively low cosmic ray activity," says Mewaldt. "We may now be returning to levels typical of past centuries."

NASA spacecraft will continue to monitor the situation as solar minimum unfolds. Stay tuned for updates.
« Last Edit: October 03, 2009, 12:40:02 PM by Body-by-Guinness »


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Night Sky Panorama
« Reply #18 on: October 11, 2009, 07:50:32 PM »
The Milky Way pic referenced above is available as part of a 360 degree panorama at this site:


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Re: Night Sky Panorama
« Reply #19 on: October 11, 2009, 08:22:38 PM »
The Milky Way pic referenced above is available as part of a 360 degree panorama at this site:

That was very cool-- Thanks!!!


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The Galaxy Zoo
« Reply #20 on: October 26, 2009, 07:57:15 AM »

Galaxy Zoo Catalogs the Universe
Credit & Copyright: SDSS, Galaxy Zoo; Composite: Richard Nowell & Hannah Hutchins
Explanation: You, too, can Zoo. The Galaxy Zoo project has been enabling citizen scientists -- inquisitive people like yourself armed with only a web browser-- to sort through the universe. Specifically, after a brief training session, volunteers are asked to use the superior image-processing power of their minds to classify and measure properties of galaxies in the vast Sloan Digital Sky Survey. In its two short years of existence, millions of galaxies have already been inspected by thousands of enthusiastic volunteers. Using Galaxy Zoo data, for example, the universe has been discovered to create no preferred spin direction, an unusual and unclassified object was found that is still being investigated, and a whole class of small galaxies dubbed Green Peas were uncovered where star formation occurs at an extraordinary high rate. Further, the Galaxy Zoo may be setting a precedent for a new type of scientific inquiry where the web helps collect, focus and coordinate human and machine intelligence. Pictured above, a group of vibrant mergers found by Zooites demonstrates the diverse zoo-like nature of many interacting galaxies in the universe.


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Craters of Phobos
« Reply #21 on: November 07, 2009, 07:37:00 AM »

Explanation: Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. Asaph Hall discovered both the Red Planet's moons in 1877. Over 9 kilometers across, Stickney is nearly half the diameter of Phobos itself, so large that the impact that blasted out the crater likely came close to shattering the tiny moon. This stunning, enhanced-color image of Stickney and surroundings was recorded by the HiRISE camera onboard the Mars Reconnaissance Orbiter as it passed within some six thousand kilometers of Phobos in March of 2008. Even though the surface gravity of asteroid-like Phobos is less than 1/1000th Earth's gravity, streaks suggest loose material has slid down inside the crater walls over time. Light bluish regions near the crater's rim could indicate a relatively freshly exposed surface. The origin of the curious grooves along the surface is mysterious but may be related to the crater-forming impact.


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The Galactic Center
« Reply #22 on: November 11, 2009, 09:16:20 AM »

Great Observatories Explore Galactic Center
Credit: NASA, ESA, SSC, CXC, and STScI
Explanation: Where can a telescope take you? Four hundred years ago, a telescope took Galileo to the Moon to discover craters, to Saturn to discover rings, to Jupiter to discover moons, to Venus to discover phases, and to the Sun to discover spots. Today, in celebration of Galileo's telescopic achievements and as part of the International Year of Astronomy, NASA has used its entire fleet of Great Observatories, and the Internet, to bring the center of our Galaxy to you. Pictured above, in greater detail and in more colors than ever seen before, are the combined images of the Hubble Space Telescope in optical light, the Spitzer Space Telescope in infrared light, and the Chandra X-ray Observatory in X-ray light. A menagerie of vast star fields is visible, along with dense star clusters, long filaments of gas and dust, expanding supernova remnants, and the energetic surroundings of what likely is our Galaxy's central black hole. Many of these features are labeled on a complementary annotated image. Of course, a telescope's magnification and light-gathering ability create only an image of what a human could see if visiting these places. To actually go requires rockets.


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Interstellar Light Echo
« Reply #23 on: November 22, 2009, 10:18:34 AM »

Light Echoes from V838 Mon
Credit: NASA and the Hubble Heritage Team (AURA/STScI)
Explanation: What caused this outburst of V838 Mon? For reasons unknown, star V838 Mon's outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this has never been seen before -- supernovas and novas expel matter out into space. Although the V838 Mon flash appears to expel material into space, what is seen in the above image from the Hubble Space Telescope is actually an outwardly moving light echo of the bright flash. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star. V838 Mon lies about 20,000 light years away toward the constellation of the unicorn (Monoceros), while the light echo above spans about six light years in diameter.


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Solar Activity Very Low
« Reply #24 on: December 09, 2009, 11:36:59 AM »
Solar geomagnetic activity is at an all time low – what does this mean for climate?
I’ve mentioned this solar data on WUWT several times, it bears repeating again. Yesterday, NOAA’s Space Weather Prediction Center released their latest data and graph of the interplanetary geomagnetic index (Ap) which is a proxy for the activity of the solar dynamo. Here is the data provided by SWPC. Note the graph, which I’ve annotated below.

The value, for the second straight month, is “3″. The blue line showing the smoothed value, suggests the trend continues downward. To get an idea of how significant this is in our history, take a look at this data (graph produced by me) from Dr. Leif Svalgaard back to the 1930’s.

The step change in October 2005 is still visible and the value of 3.9 that occurred in April of this year is the lowest for the entire dataset at that time. I’m hoping Dr. Svalgaard will have updated data for us soon.

Click for a larger image
Why is this important? Well, if Svensmark is right, and Galactic Cosmic Rays modulated by the sun’s magnetic field make a change in cloud cover on Earth, increasing it during low solar magnetic activity, we are in for some colder times.

There’s a presentation by Jasper Kirkby, CLOUD Spokesperson, CERN, which shows what we currently know about the correlations between Galactic Cosmic Rays (GCR’s) and variations in the climate.

The CLOUD experiment uses a cloud chamber to study the theorized link between GCR’s and cloud formation in Earth’s atmosphere. Kirkby talks about the results from the first CLOUD experiment and the new CLOUD experiment and what it will deliver on the intrinsic connection between GCR’s and cloud formation. This is from the Cern, one of Europe’s most highly respected centers for scientific research.

Kirkby’s one hour video presentation is hosted here. It is well worth your time to view it.

h/t to Russ Steele


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M51 Hubble Remix
« Reply #25 on: December 26, 2009, 08:39:10 AM »

M51 Hubble Remix
S. Beckwith (STScI), Hubble Heritage Team, (STScI/AURA), ESA, NASA
Additional Processing: Robert Gendler
Explanation: The 51st entry in Charles Messier's famous catalog is perhaps the original spiral nebula - a large galaxy with a well defined spiral structure also cataloged as NGC 5194. Over 60,000 light-years across, M51's spiral arms and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195. Image data from the Hubble's Advanced Camera for Surveys has been reprocessed to produce this alternative portrait of the well-known interacting galaxy pair. The processing has further sharpened details and enhanced color and contrast in otherwise faint areas, bringing out dust lanes and extended streams that cross the small companion, along with features in the surroundings and core of M51 itself. The pair are about 31 million light-years distant. Not far on the sky from the handle of the Big Dipper, they officially lie within the boundaries of the small constellation Canes Venatici.


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WSJ: Killing Killer Asteroids
« Reply #27 on: January 06, 2010, 08:04:29 AM »
Anatoly Perminov, head of the Russian Space Agency, caught scientists off guard when he called for a closed meeting of Russian scientists to counter a killer asteroid headed our way. He said that a potential impact from the asteroid Apothis around 2036 could kill hundreds of thousands of people. Immediately this conjured up images of Bruce Willis and his space cowboys riding the Space Shuttle to blow up a comet in the movie "Armageddon." Scientists, realizing that the danger is slight but real, have in fact seriously proposed various ways in which to deflect the asteroid.

As asteroids go, Apophis is a whopper, measuring 1,000 feet across, about the size of the Rose Bowl. In 2029 it will make its first pass around the earth, so close that it will travel beneath our communication satellites. In fact, you might see it whiz by overhead with binoculars. Depending on how it whips around the earth, there is a slight chance it might actually hit the earth when it returns in 2036 (but the latest calculations only show a one in a hundred thousand chance of impact).

The Russians take such a threat seriously, since a "city buster" hit Tunguska, Siberia, in 1908, flattening about a thousand square miles of forest, destroying about 100 million trees, and leaving a huge scar in the Earth. The object that struck Siberia was probably only 100 feet across, yet it created a blast about 1,000 times greater than the Hiroshima bomb. The shock waves were so intense they were detected in Europe. It created a strange glow which spread over Asia and Europe so that you could read the London papers at night. If it had hit Moscow, it would have completely flattened that city and beyond. A city-buster like that happens once every 100-300 years, with most of them hitting the oceans.

A hit from Apothis, however, would be another story. It would be a "country buster," capable of creating fire storms, shock waves, and a rain of fiery debris that would destroy an area almost the size of France, or perhaps the entire Northeast of the U.S. The energy of the impact would be roughly 100,000 times that of the Hiroshima bomb. If it hits the Pacific Ocean, it could also generate a huge tidal wave, a gigantic wall of water that could swamp most coastal cities in the Americas and Asia. An impact from an Apophis-like asteroid is estimated to happen once in a thousand years. (The worst case scenario, however, would be an impact from a "planet buster" as little as six miles across, like the one that hit Mexico and probably wiped out the dinosaurs 65 million years ago.)

Plans to counter such a hypothetical threat, however, are sketchy. A staple of science fiction is to send the Space Shuttle to blow it up. Bad idea.

First, this might only crack the asteroid, so you would have a swarm of deadly mini-asteroids headed your way. Second, the Space Shuttle can only circle the Earth; it is incapable of reaching deep space to intercept the asteroid. And it is going to be phased out this year anyway and a replacement won't be ready for about five years.

Several proposals made by scientists are currently being studied. One likely scenario is to nudge the asteroid while it is still in deep space so that it eventually misses the Earth. This deflection might be done via rockets to push the asteroid years before it passes the Earth. Or, the gravity of the spacecraft itself may be used to gently tug on its trajectory. Yet another proposal is to use mirrors and even paint to increase the pressure of sunlight so that, over decades, its trajectory is modified.

At present, none of the hardware for such a mission exists, so we will be helpless for years if a real threat emerges. And any serious proposal will require tens of billions of dollars, for new booster rockets and the complex machinery to deflect the asteroid.

But given these hard economic times, money is scarce even to maintain the current space program. The Augustine Report on the future of space travel, commissioned by NASA and presented to President Obama in October, stated that manned missions to the moon and Mars were "unsustainable" without a new injection of funds. However, it did leave open the possibility of landing on an asteroid. So one real possibility is to land a probe on the asteroid in 2029 so that scientists can study its properties as well as get a free ride through the solar system. We know so little about Apothis that it might be a solid object or just a loose collection of rocky debris held together by gravity.

Some conspiracy theorists have raised the dark possibility that any nation that can deflect an asteroid could also send it hurtling toward its enemies. But such a weapon is simply too unstable and unreliable to be taken seriously.

Indeed, scientists are applauding the Russian Space Agency for addressing the issue, even if the danger from Apophis is very slight. Sooner or later, we will face a catastrophic threat from space. Of all the possible threats, only a gigantic asteroid hit can destroy the entire planet. If we prepare now, we better our odds of survival. The dinosaurs never knew what hit them.

Mr. Kaku, a professor of theoretical physics at City College of New York, is the author of "Physics of the Impossible" (Doubleday, 2008) and host of "Sci Fi Science: Physics of the Impossible," on the Science Channel.


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Solar Magnetic Minimum
« Reply #28 on: January 07, 2010, 11:44:08 AM »
Though sunspots have appeared lately, solar magnetic activity is dropping towards zero. Implications thereof discussed here:


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Re: Astronomy
« Reply #29 on: January 07, 2010, 11:50:52 AM »
@BBG- so the lessening of sunspot activity could mean a cooling, will it be enough for an Ice Age? or will the harder to observe magnetic flux activity on the sun keep us warm enough?


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Re: Astronomy
« Reply #30 on: January 07, 2010, 11:54:20 AM »
As the piece states, sunspots are proxies for solar magnetic flux while this low rate of observed magnetic activity is close to being without precedent. As such I'd say careful observation is in order rather than predictions.


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Re: Astronomy
« Reply #31 on: January 07, 2010, 12:03:10 PM »
Watch to see if the cooling happens.......


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The Universe as we Know It
« Reply #32 on: January 20, 2010, 11:33:08 AM »

The Known Universe
Credit & Copyright: American Museum of Natural History
Explanation: What would it look like to travel across the known universe? To help humanity visualize this, the American Museum of Natural History has produced a modern movie featuring many visual highlights of such a trip. The video starts in Earth's Himalayan Mountains and then dramatically zooms out, showing the orbits of Earth's satellites, the Sun, the Solar System, the extent of humanities first radio signals, the Milky Way Galaxy, galaxies nearby, distant galaxies, and quasars. As the distant surface of the microwave background is finally reached, radiation is depicted that was emitted billions of light years away and less than one million years after the Big Bang. Frequently using the Digital Universe Atlas, every object in the video has been rendered to scale given the best scientific research in 2009, when the video was produced. The film has similarities to the famous Powers of Ten video that has been a favorite of many space enthusiasts for a generation.


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Re: Astronomy
« Reply #33 on: January 21, 2010, 03:56:00 AM »
Missed the Oort cloud, The Cometary limits, Nebulae, Clusters, and some other things on the way. (blackholes?)


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Re: Astronomy
« Reply #34 on: January 21, 2010, 05:02:18 AM »
They missed the moon, for that matter, though they showed it's orbit. As I saw it they pulled back so far from the objects in question that, as a matter of scale, theyd didn't appear in the representation.

prentice crawford

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Re: Astronomy
« Reply #35 on: January 22, 2010, 09:13:56 PM »
 Check this out, a meteorite came through the roof of a doctor's office last Monday.


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Auspicious Start
« Reply #36 on: February 20, 2010, 04:44:38 PM »
NASA recently launched the Solar Dynamic Observer, a satellite that will be used to monitor the sun. While launching the rocket went supersonic as it went through some high, thin clouds. Check out the following video and watch the shock waves in the clouds as the rocket breaks the sound barrier:


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Sun's Quiet Cycle
« Reply #37 on: June 14, 2010, 08:33:59 PM »
Sun's Strange Behavior Baffles Astronomers
By Denise Chow Staff Writer
posted: 14 June 2010
06:53 am ET
The sun's temper ebbs and flows on what scientists had thought was a pretty predictable cycle, but lately our closest star has been acting up.

Typically, a few stormy years would knock out a satellite or two and maybe trip a power grid on Earth. Then a few years of quiet, and then back to the bad behavior. But an extremely long stretch of low activity in recent years has scientists baffled and scrambling for better forecasting models.

An expected minimum of solar activity, between 2008 and 2009, was unusually deep. And while the sun would normally ramp up activity by now, heading into its next cycle, the sun may be on the verge of a weak solar cycle instead, astronomers said at the 216th meeting of the American Astronomical Society in Miami last month.

"We're witnessing something unlike anything we've seen in 100 years," said David Hathaway of NASA's Marshall Space Flight Center in Huntsville, Ala.

The sun's constant interaction with Earth makes it important for solar physicists to keep track of solar activity. Stormy periods can force special safety precautions by satellite operators and power grid managers, and astronauts can be put at risk from bursts of radiation spat out by solar storm. Scientists need to more reliably predict what's in store.

At the conference, four solar physicists presented four very different methods of measuring and tracking solar cycles. 

The sun has spots

Sunspots are areas of concentrated magnetic activity that appear as dark dots on the solar surface. The ebb and flow of the sun's magnetic activity, manifested in the appearance of sunspots, make up the solar cycle.

Typically, a cycle lasts about 11 years, taking roughly 5.5 years to move from a solar minimum, a period of time when there are few sunspots, to peak at the solar maximum, during which sunspot activity is amplified.

The previous cycle 23's extraordinary minimum recorded the highest number of days without sunspots that researchers had seen since 1913, said Hathaway.

Hathaway and his team of researchers measured what is called the meridional flow, which is the circulation of stellar material from the sun's equator toward the poles and back again. This flow can often influence a cycle's strength.

The scientists examined the changes in the structure of the flow, and the levels of geomagnetic activity, as they corresponded to the minimums and maximums of the previous solar cycles.

"We found that there were variations in the strength of that flow," Hathaway said. "The last minimum in 1996, that velocity was about 11 meters per second (about 22 miles an hour), which is pretty slow for an object as big as the sun. That flow slowed down as we went to maximum in 2001."

The meridional flow then quickly increased again, and by 2004, it was faster than it was at the last maximum, said Hathaway. This flow continued to stay fast on the approach to this most recent minimum.

"My suspicion is that this sunspot cycle 23 was a weaker cycle than the last two, with fewer sunspots and weaker magnetic fields. These may feed into what happens with the meridional flow that is going to lead to another weak cycle."

Hathaway predicts that cycle 24 should reach its peak in mid-2013 at about half the size of the last three cycles.

The sun's out of sync

In a different approach, Sushanta Tripathy of the National Solar Observatory used the frequencies of acoustic oscillations to look for signatures of changes in the solar activity cycle.

Tripathy found that changes in acoustic frequencies were, for the most part, in phase with solar activity. But, during the extended minimum, he noticed that the frequencies of waves that cover a large portion of the solar interior became out of sync with solar activity.

"We find that the frequencies of sound waves that travel to the deep interior show an early minimum during late 2007, while the waves that are confined to near the surface show the signature of minimum in late 2008, nearly coinciding with solar activity minimum."

The two seismic lulls detected using acoustic oscillation have not been seen before in previous cycles, said Tripathy, leading researchers to conclude that the extended minimum between cycles 23 and 24 is quite unusual.

Jet streams on the sun

Frank Hill, also of the National Solar Observatory, took a separate approach, attempting to predict the sunspot cycle based on a phenomena on the sun that can be likened to solar jet streams.

This east-west flow on the surface of the sun was first discovered in 1980, and is known as "torsional oscillation."

The jet stream exists at a depth of at least 65,000 miles (about 105,000 kilometers) below the solar surface, and Hill and his team of researchers were able to examine its behavior at a depth of 600 miles (966 km).

"The position of the magnetic field is very highly correlated with the position of this flow," Hill said. "From helioseismology, we see the flows for two prominent cycles – Cycle 23, the cycle that we're coming out of, and Cycle 24, the cycle that we're in now."

It turns out that the flow appears well before the level that solar activity spikes. This led the researchers to conclude that there is some sort of triggering mechanism that appears before the onset of activity.

While observations of the solar jet could one day be useful for predicting the timing of the solar cycles, a larger data set is still required to ensure the method's accuracy.

"We're definitely going to need several cycles to improve the predictions," Hill said.

Further investigation will also be needed to determine whether the jet stream is a cause or effect of the solar cycle.

Our magnetic star

In yet another approach, Julia Saba of SP Systems and NASA's Goddard Space Flight Center in Greenbelt, Md., used X-ray and magnetic field strength indicators in order to predict the precise time mark for the onset of solar cycles.

Saba used magnetic maps of the sun, called synoptic charts, to observe solar cycles 21 through 23 and into 24. By evaluating trends in X-ray activity, Saba was able to predict the onset approximately 18 months ahead of time, and was accurate to within two months.

"By May of 2010, we see that cycle 24 is clearly underway, though things are still pretty quiet in the southern hemisphere in general," Saba said.

This method of determining a solar cycle's onset could be a valuable way to compare the different phases in solar activity because it can be observed in near real-time, Saba explained.

"It's a little easier to tell in real time than by solar maximum or solar minimum," she said.

While the four ways of monitoring solar activity take different approaches, the researchers are all in agreement that we are witnessing an interesting minimum. And while these methods could be useful for future studies of solar cycles, they all require further research.

"One problem we have with all solar cycle studies is the statistics of small numbers," Hathaway said. "Even with 23 sunspot cycles, it's not enough. What we've seen today are some newer measurements that weren't available even two cycles ago that are shedding new light. We need to be careful with using what we've seen from one or two cycles to make inferences for all of them."


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Southern Lights
« Reply #38 on: June 21, 2010, 06:53:01 AM »
The green fire of the southern lights
Check this out! The aurora australis — the southern lights — snakes its way across the Earth’s magnetic field as seen from above!

Wow, that’s slick. It was taken on May 29th by an Expedition 23 astronaut aboard the International Space Station (it’s unknown which one; NASA and the astronauts decided to give the expedition the credit, not an individual crew member). At that moment, the ISS was 350 km (190 miles) above the Indian ocean, and the astronaut was looking south. You can see the limb of the Earth and some stars in the background as well. Click the picture to get a bigger version with more detail.

This aurora was probably caused by subatomic particles from an explosive event called a coronal mass ejection from the Sun five days earlier. The particles interact with our magnetic field, which channels them to the north and south poles. They slam into the air, ripping electrons off the atoms and molecules. When the atoms recombine, they give off light. The green glow seen here is characteristic of oxygen.
The aurorae are usually between 80 – 160 km (50 – 100 miles) above the Earth’s surface, so the ISS was actually higher up. However, the station was a couple of thousand kilometers away from the lights when this shot was taken.
I’ve only seen the northern lights (technically, the aurora borealis) once, when I lived in Maryland years ago… and it was just a faint red smear to the north. Someday I hope to see it in its full glory. But even then, it must pale — literally — to seeing such a thing from space.
Picture credit: NASA/Expedition 23


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Re: Astronomy
« Reply #39 on: June 21, 2010, 02:04:00 PM »
That is amazing!  This is a very cool thread.  I used to want to be an astronomer when I was a boy.  This thread is a good reminder of why!


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Lightning Show
« Reply #40 on: July 22, 2010, 08:13:15 PM »

Lightning Over Athens
Credit & Copyright: Chris Kotsiopoulos
Explanation: Have you ever watched a lightning storm in awe? Join the crowd. Oddly, nobody knows exactly how lightning is produced. What is known is that charges slowly separate in some clouds causing rapid electrical discharges (lightning), but how electrical charges get separated in clouds remains a topic of much research. Lightning usually takes a jagged course, rapidly heating a thin column of air to about three times the surface temperature of the Sun. The resulting shock wave starts supersonically and decays into the loud sound known as thunder. Lightning bolts are common in clouds during rainstorms, and on average 6,000 lightning bolts occur between clouds and the Earth every minute. Pictured above, an active lightning storm was recorded over Athens, Greece earlier this month.


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CME & Northern Lights
« Reply #41 on: August 05, 2010, 07:21:19 PM »
Recent coronal mass ejection made for a spectacular display of Northern Lights, with videos captured at the link:

prentice crawford

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Re: Astronomy
« Reply #42 on: August 18, 2010, 08:08:03 PM »
 Baby Black Hole



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Sculptures of Hydrogen & Dust
« Reply #43 on: September 20, 2010, 03:15:52 PM »

Cosmic Ice Sculptures
In the cold vacuum of space, radiation from massive stars carves away at cold molecular clouds, creating bizarre, fantasy-like structures. These pillars of cold hydrogen and dust, imaged by the Hubble Space Telescope, are located in the Carina Nebula. Violent stellar winds and powerful radiation from massive stars sculpt the surrounding nebula.

This image of dust pillars in the Carina Nebula is a composite of 2005 observations taken of the region in hydrogen light (light emitted by hydrogen atoms) along with 2010 observations taken in oxygen light (light emitted by oxygen atoms), both times with Hubble's Advanced Camera for Surveys. The immense Carina Nebula is an estimated 7,500 light-years away in the southern constellation Carina.

Image Credit: NASA, ESA, and the Hubble Heritage Project (STScI/AURA)


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Ef Waldo, Where's Pluto?
« Reply #44 on: September 20, 2010, 03:18:44 PM »
2nd post.

When Pluto was discovered 80 years ago, it happened to be moving through Gemini, a part of the sky that had a lot of stars. Clyde Tombaugh did an amazing job finding it, since it was almost lost among those stars.
I wonder if he could’ve found it had he been looking earlier this year? "Amateur" astronomer Anthony Ayiomamitis sent me this image he took of Pluto as was in Sagittarius, the most densely-packed area of the sky!

[Click to undwarfplanetate.]
Hard to spot, isn’t it? Pluto is unresolved in the picture, so it looks like just another star. And there are a lot of stars here; this region of sky is actually a cluster called Messier 24 (or just M24, and it’s pronounced "MEZ-ee-ay", since Charles Messier was French); the two dark splotches are thick dust clouds called Barnard 92 and 93. Finding Pluto in this ain’t easy.

… or is it? When I first looked over the picture, I found Pluto almost immediately, and then laughed, because I know a secret. First, take a look… can you find it?
OK, here’s the secret: this is a color picture, which means Anthony had to take four images, one each through a red, green, and blue filter, and one unfiltered. The stars all look good because they don’t move, but by the time he took the red image Pluto had moved a bit compared to the stars’ positions. So when my eye happened to catch a bright red spot in the image, I knew right away I was seeing Pluto. The picture here has Pluto’s position marked; click it to see the full sized version.
In modern terms, Pluto is pretty bright; I’ve never seen it with my own eyes through a telescope, but using a small ’scope equipped with a digital camera I’ve gotten decent images of it in under a minute! But Tombaugh didn’t have that, nor did he have a computer to tell him where it was. He had to take picture after picture, night after night, guiding the telescope, developing the glass plates, then comparing each picture one after another. That’s why it took him months to find Pluto!
And remember, he didn’t even know if it existed!
Astronomy is not for the faint of heart. But for those of us who love it, it truly is something we do from the heart.


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The Big Red Spot
« Reply #45 on: September 27, 2010, 08:23:27 AM »
Blogs / Bad Astronomy

The Great Red Spot, almost true size

One of the fun things about astronomical data is that a lot of it is public; if you know where to look you can find it. And a lot of telescopes and space probes produce so much data there’s simply no way professional scientists can look at it all… giving "amateurs" (in the sense that they aren’t professionals, not that they aren’t possessed of vast talent) a chance to create images from these data.
And man oh man, am I glad some folks do just that. Behold!

WOW! That is, of course, Jupiter’s Great Red Spot as seen by the Voyager 1, a spacecraft that flew by Jupiter more than 30 years ago now. The gifted astrophotographer Björn Jónssen reprocessed the images to produce this simply stunning portrait of the centuries-old storm. Remember: when you look at this, you’re seeing a storm that is easily twice as big as the entire Earth!
Björn posts his work on the terrific Unmanned Spaceflight board, a great place to see what folks are doing with space imagery, and where you’ll find other (and some far bigger) versions of this magnificent shot.
For more details on this, Emily Lakdawalla has written it up at the Planetary Society blog. She has lots of details and insight on this, and I strongly urge you to give it a read. I think it’s wonderful that so much of the sky has opened up for everyone.
Image credit: NASA / JPL / Björn Jónsson

Big image here:


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Near Earth Orbit Miss
« Reply #46 on: October 12, 2010, 09:33:38 AM »
For my money, the "sky is falling" global warming types ought to be paying more attention to stuff like this. Of course rocks in near earth orbit don't provide reason enough to tell everyone what choices they ought to make and how they ought to live:



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DIY Space Cam
« Reply #47 on: October 14, 2010, 08:08:42 AM »
Some wicked cool homebrew space photography:


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Sun Gets Frisky
« Reply #48 on: October 21, 2010, 09:25:02 AM »

Crackling with Solar Flares
Fast-growing sunspot 1112 is crackling with solar flares. So far, none of the blasts has hurled a substantial CME, or coronal mass ejection, toward Earth. In addition, a vast filament of magnetism is cutting across the sun's southern hemisphere. This filament is so large it spans a distance greater than the separation of Earth and the moon. A bright 'hot spot' just north of the filament's midpoint is UV radiation from sunspot 1112. The proximity is no coincidence; the filament appears to be rooted in the sunspot below. If the sunspot flares, it could cause the entire structure to erupt. Thus far, none of the flares has destabilized the filament.

Image Credit: NASA


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Astounding Comet Closeups
« Reply #49 on: November 04, 2010, 09:44:27 AM »
I'm floored:

Amazing close-ups of comet Hartley 2!

Just an hour ago as I write this, the NASA spacecraft EPOXI passed just 700 km from the nucleus of comet Hartley 2! The flyby was successful, and it took incredible images of the comet’s solid heart:

Wow! These images are in order of approach (left to right, top to bottom), as EPOXI flew by. We knew from ground-based radar that the nucleus wasn’t round, but these pictures clearly show it to be shaped like a peanut. That’s not too surprising; this shape is common in asteroids and comet nuclei. But what detail! You can see the surface is irregular and contoured. There’s a groove of some sort on the left side, and what might be an impact crater or pit on the very left tip.
And those bright streamers of light? Those are jets of gas shooting away from the comet, formed when frozen material on the comet surface gets heated by the Sun, expands, and shoots away!

Amazing. And very lovely.
Here’s the fourth image a bit bigger:

Looking more carefully, weird things pop up. The round ends of the nucleus are bumpy and rough, indicating material is loosely aggregated there. But the waist looks smooth! There also appear to be bands of material circling the round ends separating the waist from the tips. You can also see what looks like a large boulder or spire of ice on the right side of the smooth section, poking up into the Sun. That’s a testament to the weak gravity of the comet; the nucleus is only about 2.2 km (1.4 miles) across, so there’s not much mass there. That piece jutting up is probably about a hundred or so meters high.

[UPDATE to note that there will be a live press conference at 20:00 UT (16:00 Eastern US time) where scientists will discuss these images. You can watch it live on NASA TV and on JPL's Ustream channel. Also, Emily Lakdawalla has written her thoughts on the comet on her blog, too.]
And mind you, these are not the highest-resolution images! These are medium-res; even better ones will be coming soon. Trust me, as soon as they’re available I’ll have them here. I want to add that this part of the mission is a bonus; the mission was extended after the Deep Impact part back in 2005. Renamed EPOXI, it has gone on to do some amazing work in characterizing how we look for extrasolar planets. It was a very smart decision to continue this mission, and now we have these images and data, a whole new comet to investigate and understand.

Congratulations to the EPOXI team for a successful and amazing cometary encounter!

NASA feed of the satellite pass: