Sand dunes on Mars from MRO's HiRISE camera. Credit: NASA/JPL University of Arizona
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I see the Bad Astronomer has beat me to the punch by posting this image before I could. But what an amazing and gorgeous image of dunes on Mars! However, my initial thought when I saw this on the HiRISE webpage was perhaps this was the first long-awaited look at Phil’s tattoo. Seriously, doesn’t this look like it could be body art? The dunes even have a Phil-like flesh color. But this wonderful image was taken by the HiRISE camera on the Mars Reconnaissance Orbiter. There is a great database of dune images gathered for the US Geological Survey on the HiRISE website, and below, take a gander at more lovely dune images:
Click on each image to learn more from the HiRISE website.
More Martian dunes from HiRISE.Russell Crater dunes. Credit: Credit: NASA/JPL/University of Arizona Dunes in the Western Nereidum Montes. Credit: NASA/JPL University of ArizonaSand dunes. Credit: NASA/JPL/University of ArizonaDark dunes. Credit: NASA/JPL/University of Arizona
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There are thousands of satellites overhead in space right now, and many of them are being used to map every single square meter of planet Earth. And many of these images are being freely distributed on the Internet so you can access them through any browser. If you’re looking for a satellite map, there are many services out there that can help you out.
Probably the easiest and best place to start is with the Google Maps service from Google. This allows you to see a satellite map of the entire Earth. You can drag around the map to browse around the planet, and you can zoom out and in right down to the highest resolution images they have in their server. In many cases this means you can see your house, your yard, and even your car parked out in the street. You can also type in a specific address location and go straight there. There are street maps you can overlay or remove, you can get driving directions, and much more. And the Google Maps API has been made available by Google to other websites, so people are developing mashups that let you track running routes and find the nearest bathroom.
An even cooler satellite mapping service is Google Earth. Unlike Google Maps, you have to download Google Earth to your local PC, Mac or Linux machine (there’s even an iPhone version). Then you get this cool spinning 3-D version of the Earth. You can zoom out and in, type in a specific location address or geocode to find any spot on Earth. They also have a big library of additional layers that you can put over top, to see additional information mapped on the Earth. It’s well worth the download.
Another good service is TerraServer; they let you buy satellite maps if you want a nice printed version for your wall. If you don’t want to use Google, there are similar mapping tools from Microsoft and Yahoo.
We have written many articles about how satellites are being used to map the Earth. Here’s an article about how scientists use satellite photos to track penguin poop from space, and how Google’s maps had a satellite view of Obama’s inauguration.
We have also recorded an episode of Astronomy Cast all about Earth. Listen here, Episode 51: Planet Earth.
Accurate timing of the incoming ENAs allows the IBEX team to obtain a higher resolution in the latitudinal direction. The inset at right shows some of the fine detail of the ribbon. Credit: Southwest Research Institute (SwRI)
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Since it launched a year ago, the Interstellar Boundary Explorer (IBEX) has been monitoring heliosphere and how our Sun interacts with and the local interstellar medium — the gas and dust trapped in the vacuum of space. The first results from the mission, combined with data from the Cassini mission, are showing the heliosphere to be different from what researchers have previously thought. Data show an unexpected bright band or ribbon of surprisingly high-energy emissions. “We knew there would be energetic neutral atoms coming in from the very edge of the heliosphere, and our theories said there would be small variations in their emissions,” said David McComas, IBEX Principal Investigator at a press conference on Thursday. “But instead we are seeing two-to-three hundred percent variations, and this is not entirely understood. Whatever we thought about this before is definitely not right.”
The energies IBEX has observed range from 0.2 to 6.0 kiloelectron volts, and the scientists said its flux is two to three times greater than the ENA activity throughout the rest of the heliosphere. McComas and his colleagues said that no existing model can explain all the dominant features of this “ribbon.” Instead, they suggest that these new findings will prompt a change in our understanding of the heliosphere and the processes that shape it. This image illustrates one possible explanation for the bright ribbon of emission seen in the IBEX map. The galactic magnetic field shapes the heliosphere as it drapes over it. The ribbon appears to trace the area where the magnetic field is most parallel to the surface of the heliosphere (the heliopause). Credit: Southwest Research institute
McComas suggested that the energetic neutral atom (ENA) ribbon could be caused by interactions between the heliosphere and the local interstellar magnetic field. “The local interstellar magnetic field is oriented in such a way that it correlates with the ribbon. If you ‘paint’ the ribbon on the boundary of the heliosphere, the magnetic field is like big bungie cords that pushing in along the sides and at southern part of the heliosphere. Somehow the magnetic field seems to be playing a dominant roll in these interactions, but we don’t know it could produced these higher fluxes. We have to figure out what physics were are missing.”
The solar wind streaks away from the sun in all directions at over a millions kilometers per hour. It creates a bubble in space around our solar system.
For the first ten billion kilometers of its radius, the solar wind travels at over a million kilometers per hour. It slows as it begins to collide with the interstellar medium, and the point where the solar wind slows down is the termination shock; the point where the interstellar medium and solar wind pressures balance is called the heliopause; the point where the interstellar medium, traveling in the opposite direction, slows down as it collides with the heliosphere is the bow shock. The heliosphere. Credit: NASA
The Voyager spacecraft have explored this region, but didn’t detect the ribbon. Team member Eric Christian said the ribbon wound in between the location of Voyager 1 and 2, and they couldn’t detect it in their immediate areas. Voyager 1 spacecraft encountered the helioshock in 2004 when it reached the region where the charged particles streaming off the sun hit the neutral gas from interstellar space. Voyager 2 followed into the solar system’s edge in 2007. While these spacecraft made the first explorations of this region, IBEX is now revealing a a more complete picture, filling in where the Voyagers couldn’t. Christian compared Voyager 1 and 2 to be like weather stations while IBEX is first weather satellite to provide more complete coverage.
McComas said his first reaction when the data started coming in was that of terror because he thought something must be wrong with the spacecraft. But as more data kept coming back each week, the team realized that they were wrong, and the spacecraft was right.
“Our next steps will be to go through all the detailed observations and rack them up against the various models and go find what it is that we are missing, what we’ve been leaving out,” he said.
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Theoretical physics has brought us the notion that our single universe is not necessarily the only game in town. Satellite data from WMAP, along with string theory and its 11- dimensional hyperspace idea has produced the concept of the multiverse, where the Big Bang could have produced many different universes instead of a single uniform universe. The idea has gained popularity recently, so it was only a matter of time until someone asked the question of how many multiverses could possibly exist. The number, according to two physicists, could be “humongous.”
Andrei Linde and Vitaly Vanchurin at Stanford University in California, did a few back-of- the- envelope calculations, starting with the idea that the Big Bang was essentially a quantum process which generated quantum fluctuations in the state of the early universe. The universe then underwent a period of rapid growth called inflation during which these perturbations were “frozen,” creating different initial classical conditions in different parts of the cosmos. Since each of these regions would have a different set of laws of low energy physics, they can be thought of as different universes.
Linde and Vanchurin then estimated how many different universes could have appeared as a result of this effect. Their answer is that this number must be proportional to the effect that caused the perturbations in the first place, a process called slow roll inflation, — the solution Linde came up with previously to answer the problem of the bubbles of universes colliding in the early inflation period. In this model, inflation occurred from a scalar field rolling down a potential energy hill. When the field rolls very slowly compared to the expansion of the universe, inflation occurs and collisions end up being rare.
Using all of this (and more – see their paper here) Linde and Vanchurin calculate that the number of universes in the multiverse and could be at least 10^10^10^7, a number which is definitely “humungous,” as they described it.
The next question, then, is how many universes could we actually see? Linde and Vanchurin say they had to invoke the Bekenstein limit, where the properties of the observer become an important factor because of a limit to the amount of information that can be contained within any given volume of space, and by the limits of the human brain.
The total amount of information that can be absorbed by one individual during a lifetime is about 10^16 bits. So a typical human brain can have 10^10^16 configurations and so could never distinguish more than that number of different universes.
The number of multiverses the human brain could distinguish. Credit: Linde and Vanchurin
“So, the total number of possibilities accessible to any given observer is limited not only by the entropy of perturbations of metric produced by inflation and by the size of the cosmological horizon, but also by the number of degrees of freedom of an observer,” the physicists write.
“We have found that the strongest limit on the number of different locally distinguishable geometries is determined mostly by our abilities to distinguish between different universes and to remember our results,” wrote Linde and Vanchurin. “Potentially it may become very important that when we analyze the probability of existencse of a universe of a given type, we should be talking about a consistent pair: the universe and an observer who makes the rest of the universe “alive” and the wave function of the rest of the universe time-dependant.”
So their conclusion is that the limit does not depend on the properties of the multiverse itself, but on the properties of the observer.
They hope to further study this concept to see if this probability if proportional to the observable entropy of inflation.
Chandrayaan-1 SARA measurements of hydrogen flux recorded on the Moon on 6 February 2009. Credits: Elsevier 2009 (Wieser et al.), ESA-ISRO SARA data
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In late September, a team of scientists announced finding water molecule signatures across much of the Moon’s surface. Now, a second instrument on board India’s Chandrayaan-1’s lunar orbiter confirms how the water is being produced. The Sub keV Atom reflecting Analyzer (SARA) corroborates that electrically charged particles from the Sun interact with the oxygen present in some dust grains on the lunar surface to produce water. But the results bring out a new mystery of why some protons get reflected and not absorbed.
Scientists likened the Moon’s surface to a big sponge that absorbs the electrically charged particles. The lunar surface is a loose collection of irregular dust grains, or regolith, and the incoming charged particles should be trapped in the spaces between the grains and absorbed. When this happens to protons they are expected to interact with the oxygen in the lunar regolith to produce hydroxyl and water.
The SARA results confirm findings from Chandrayaan-1’s Moon Mineralogy Mapper (M3) that solar hydrogen nuclei are indeed being absorbed by the lunar regolith; however SARA data show that not every proton is absorbed. One out of every five rebounds into space. In the process, the proton joins with an electron to become an atom of hydrogen.
“We didn’t expect to see this at all,” says Stas Barabash, Swedish Institute of Space Physics, who is the European Principal Investigator for SARA. The Sub Kev Atom reflecting Analyser (SARA)on board the lunar mission Chandrayaan-1. SARA is the first-ever lunar experiment dedicated to direct studies of plasma-surface interactions in space. Credits: ISRO/ESA/Swedish Institute Of Space Physics
Although Barabash and his colleagues do not know what is causing the reflections, the discovery paves the way for a new type of image to be made. Unfortunately, since the Chandrayaan-1 orbiter is no longer functioning, new data can’t be taken. However, the team can work with data already collected to further study the process.
The hydrogen shoots off with speeds of around 200 km/s and escapes without being deflected by the Moon’s weak gravity. Hydrogen is also electrically neutral, and is not diverted by the magnetic fields in space. So the atoms fly in straight lines, just like photons of light. In principle, each atom can be traced back to its origin and an image of the surface can be made. The areas that emit most hydrogen will show up the brightest.
While the Moon does not generate a global magnetic field, some lunar rocks are magnetized. Barabash and his team are currently creating images from collected data, to look for such ‘magnetic anomalies’ in lunar rocks. These generate magnetic bubbles that deflect incoming protons away into surrounding regions making magnetic rocks appear dark in a hydrogen image.
The incoming protons are part of the solar wind, a constant stream of particles given off by the Sun. They collide with every celestial object in the Solar System but are usually stopped by the body’s atmosphere. On bodies without such a natural shield, for example asteroids or the planet Mercury, the solar wind reaches the ground. The SARA team expects that these objects too will reflect many of the incoming protons back into space as hydrogen atoms.
Scientists with the ESA’s BepiColombo mission to Mercury are hoping to study the interaction between charged particles and the surface of Mercury. The spacecraft will be carrying two similar instruments to SARA and may find that the inner-most planet is reflecting more hydrogen than the Moon because the solar wind is more concentrated closer to the Sun.
Space shuttle Atlantis on top of one of the mobile launcher platforms at Launch Pad 39A. Credit: NASA
Space shuttle Atlantis rolled out to Launch Pad 39A on Wednesday in preparation for the next shuttle flight, STS-129, currently scheduled for liftoff on Nov. 12, 2009 at 4:04 p.m. EST. And in case you haven’t heard, for the first time, NASA is inviting those who use Twitter to view a space shuttle launch in person. The first 100 people who sign up on NASA’s website will be granted access to Kennedy Space Center on Nov. 11 and 12 for the opportunity to take a tour of the facilities, view the space shuttle launch and speak with shuttle technicians, engineers, astronauts and managers. The Tweetup will include a “meet and greet” session to allow participants to mingle with fellow Tweeps and the staff behind the tweets on @NASA. An additional 50 registrants will be added to a waitlist. Registration opens at noon EDT on Friday, Oct. 16. To sign up and for more information click here.
Those chosen are responsible for their own transportation, lodging and food. To be eligible, you must have a Twitter account.
“This will be NASA’s fifth Tweetup for our Twitter community,” said NASA spokesman Michael Cabbage. “Each event has provided our followers with inside access to NASA personnel, including astronauts. The goal of this particular Tweetup is to share the excitement of a shuttle launch with a new audience.”
The STS-129 mission will be heading to the International Space Station to deliver two control moment gyroscopes and other equipment, plus the EXPRESS Logistics Carrier 1 and 2 to the station. The mission will feature three spacewalks.
This is also scheduled to be the last space shuttle crew rotation flight, and will return station crew member Nicole Stott to Earth.
STS-129 will be commanded by Charlie Hobaugh and piloted by Barry Wilmore. Mission Specialists are Robert Satcher Jr., Mike Foreman, Randy Bresnik and Leland Melvin. Wilmore, Satcher and Bresnik will be making their first trips to space.
A collage of 21-day old Moons, sketched by Galileo, (left), an image from Jane Houston Jones' telescope, center, and Jane's sketch, right.
[/caption] A collage of 21-day old Moons, sketched by Galileo, (left), an image from Jane Houston Jones’ telescope, center, and Jane’s sketch, right.
Amateur astronomers have different ways of documenting their observing sessions, such as taking astrophotos or keeping a logbook. Others, like Jane Houston Jones, employ an age-old method used by Galileo Galilei himself: they take pen in hand and sketch what they see through the lens of their telescope. During this International Year of Astronomy, Jones – an amateur astronomer who also happens to work at the Jet Propulsion Laboratory — wanted to do something special to honor the legacy of Galileo, and decided to follow through with something she has been considering for quite a while. Jones is recreating all of Galileo’s astronomical sketches as she looks through a telescope similar in size to the one used by the father of modern observational astronomy. “Every time I look through a small telescope at these same objects that Galileo did, it just gives me chills,” Jones said. “It fills me with wonder every time I think that I’m seeing the same view Galileo saw 400 years ago, and I wonder what was going through his mind as he made his observations.”
Sketching isn’t new for Jones, a Senior Outreach Specialist for the Cassini mission to Saturn. “When I made my very first telescope in 1989, the first thing I did was draw pictures of what I observed,” she said, “and I’ve just continued it. It makes a wonderful journal or diary of everything you do with a telescope.” Jane Houston Jones' telescope alongside a replica of Galileo's telescope. Credit: Jane Houston Jones
Galileo’s first telescope had an objective diameter of 37 mm, a focal length of 980 mm, and the instrument’s magnification was 21.
Jones is using a small refractor, a Televue Ranger, which has an objective diameter of 70mm, a focal length of 480mm, and using a 25mm Zeiss Abbe Orthoscopic eyepiece, yields a comparable magnification of 19.
“My field of view is bigger than what Galileo had, but I have little less magnification, so in the end I’m getting about the same view that Galileo did. But 400 years later, with better optics, mine is easier to see,” she said. “For effect, I’m also using just a manual mount where I have to move the telescope myself up and down and side to side.”
But using a small telescope to make sketches is a challenging task, Jones is finding, and she has gained new appreciation for Galileo’s original astronomical drawings. “I’ve never observed and sketched through a small telescope before, so it’s a challenge,” she said. “I’ve always loved sketching the Moon, but I’ve usually used a much larger telescope and sketched one crater or a small feature on the terminator. I’ve never tried to sketch the whole Moon at once before, but I wanted to make the same sketches as Galileo. With his telescope, Galileo could only see a tiny portion of the Moon, maybe about 1/8 of the surface at once. And when he looked at a star cluster he couldn’t see, for example, all of the Pleiades in one view. So, I now wonder what kind of worksheet he prepared to try and connect the different views together into the larger view, because he certainly had to sweep through several views to make one sketch.” Galileo's sketch of Jupiter and its moons, and also Neptune.
Jones said her most memorable views during this Galilean exercise are some of the most basic things Galileo saw. “To me, the very coolest things I saw are the Galilean moons. Everybody who looks at Jupiter through a telescope sees the three or four little dots as the moons are orbiting around the planet. We take that for granted, seeing the moons lined up along the equator of Jupiter. But when Galileo looked at them, it was just amazing that he saw their movement and made the discovery.”
One of her most significant views included an object that Galileo didn’t realize was another, yet undiscovered planet. “Galileo also did a sketch showing the Galilean moons and one additional fixed star, which using modern astronomy software, we can go back to the same day of his observations, and now we know that fixed star was Neptune. To me, that was just so amazing to see all in one eyeview Jupiter, the four moons and another planet that at Galileo’s time, hadn’t been discovered yet, and wouldn’t be discovered for several hundred years.” Jane Houston Jones' sketch of Saturn from 2002. Courtesy Jane Houston Jones
Now, she is working sketching Saturn, which is interesting given Saturn just went through equinox, meaning the rings have “disappeared” from our vantage point on Earth. “When Galileo first looked at Saturn, he thought he saw three objects – the planet and the rings on both sides of Saturn, And of course he looked at Saturn again a few years later and the rings had disappeared. I’m working on getting my sketches of Saturn over the years to try and match up what Galileo sketched.”
After Saturn, Venus is her next target for sketching.
Since Jones has been sketching for 20 years, she said she won’t quit after the IYA. “To me it makes a diary that follows a tradition that goes back centuries. I like to do that, because I can then take my sketches and look at Galileo’s or other centuries-old views of the same objects and I have a connection with those observers because we held a pen or pencil in our hand while looking through an eyepiece and made notes of what we see. I like that. Plus it’s such a fun project and I’m learning so much about Galileo’s observations, as well as some of the current scholars who are documenting his observations and researching his sketches. It’s a great learning experience, besides the artistic and personal satisfaction of drawing something. It’s a great history lesson.”
In her day job at JPL, Jones does educational outreach for the Cassini mission, working with the public, museums, planetariums, astronomy clubs, and an international network of volunteers called the Saturn Observation Campaign. Additionally she is the Twitter voice of Cassini. But she also creates a monthly podcast for JPL called “What’s Up” about what is visible in the night sky each month. “It’s really neat to have astronomy part of my day job as well as my passion in life,” she said.
For more of Jones’ observations and sketches, check out her website, and this specific page about observing with a small refractor.
Aurora Australis over the elevated station at Amundsen-Scott South Pole Station, Antarctica. Credit: Calee Allen, National Science Foundation
Aurora australis (also known as the southern lights, and southern polar lights) is the southern hemisphere counterpart to the aurora borealis. In the sky, an aurora australis takes the shape of a curtain of light, or a sheet, or a diffuse glow; it most often is green, sometimes red, and occasionally other colors too.
Like its northern sibling, the aurora australis is strongest in an oval centered on the south magnetic pole. This is because they are the result of collisions between energetic electrons (sometimes also protons) and atoms and molecules in the upper atmosphere … and the electrons get their high energies by being accelerated by solar wind magnetic fields and the Earth’s magnetic field (the motions are complicated, but essentially the electrons spiral around the Earth’s magnetic field lines and ‘touch down’ near to where those lines become vertical).
So by far the best place to see aurorae in the southern hemisphere is Antarctica! Oh, and at night too. When the solar cycle is near its maximum, aurora australis are sometimes visible in New Zealand (especially the South Island), southern Australia (especially Tasmania), and southern Chile and Argentina (sometimes in South Africa too).
About the colors: the physics is similar to what make a flame orange-yellow when salt is added to it (i.e. specific atomic transitions in sodium atoms); green and red come from atomic oxygen; nitrogen ions and molecules make some pinkish-reds and blue-violet; and so on.
How high are aurorae? Typically 100 to 300 km (this is where green is usually seen, with red at the top), but sometimes as high as 500 km, and as low as 80 km (this requires particularly energetic particles, to penetrate so deep; if you see purple, the aurora is likely to be this low).
There’s a good aurora FAQ at this University of Alaska Fairbanks’ Geophysical Institute site (though it, naturally, concentrates on the borealis!).
Aurorae on other planets? Well, as there are strong magnetic fields plus (not so strong) solar wind plus (really deep) atmosphere on Jupiter and Saturn, they have spectacular aurorae, in rings around their magnetic poles (which are closer to their rotation poles than Earth’s are). Aurorae have also been imaged on Venus, Mars, Uranus, Neptune, and even Io (atmosphere? solar wind? magnetic fields? sure, but very different than on planets).
Here’s this week’s image for the WITU Challenge, to test your visual knowledge of the cosmos. You know what to do: take a look at this image and see if you can determine where in the universe this image is from; give yourself extra points if you can name the spacecraft responsible for the image. We’ll provide the image today, but won’t reveal the answer until tomorrow. This gives you a chance to mull over the image and provide your answer/guess in the comment section. Please, no links or extensive explanations of what you think this is — give everyone the chance to guess.
This is Mars moon Phobos, as seen by the Mars Reconnaissance Orbiter’s HiRISE Camera. And yes, the big impression is Stickney Crater. See more images of Phobos (and larger version), as well as more info from the HiRISE site here.
Right now, we don’t have a “hide” feature on comments. Sorry.
2012 poster, with a little addition by N. Atkinson
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In a rather cruel media ploy, the creators of the upcoming science fiction movie “2012” are purposely feeding the flames of internet panic about the ridiculous claims that the world will end in 2012. This viral marketing campaign has created fake science websites and encourages people to search for “2012” on the Web. While there are many websites, like Universe Today, which provide solid and methodical evidence that the 2012 hysteria is complete nonsense, hordes of other sites out there are full of gobbledygook and a gross misstating of what they claim to be scientific evidence that some astronomical event will decimate our planet. Why are these hoaxers doing this? For the oldest reason ever: for profit and notoriety. If you visit their websites, most are trying to sell books or videos.
For those reading this article because you have concerns about 2012, we encourage you to read our complete series of articles on 2012, and it won’t cost you a thing. The articles were written by Dr. Ian O’Neil, who has a PhD in solar physics. Additionally, below is a list of other resources that should help answer any questions or concerns you may have on this topic:
1. NASA scientist Dr. David Morrison Dr. Morrison, a world-renowned expert on the solar system (and asteroid impacts) has published a free pdf, “Doomsday 2012, Planet Nibiru and Cosmophobia,” a concise summary of the claims and answers containing solid scientific responses. It is published by the Astronomical Society of the Pacific as a public service.
2. Morrison also serves as the public scientist for NASA’s “Ask an Astrobiologist” service, where he answers questions for the public. You’ll find many questions and answers about 2012 there, as well as other space topics.
3. The 365 Days of Astronomy podcast has a couple of great, short podcasts that address the 2012 claims, where you can get lots of information in about 10 minutes of your time. Will the World End in 2012? provides an overview of all 2012 doomsday hoaxes, and “Ancient Astronomy: The Mayans” discusses the significance of the Mayan calendar and, briefly, how the world is not going to end in 2012.
4. The Griffith Observatory has a great, concise page on the different claims called “The Truth About 2012: The End is NOT Near,” written by astronomer Dr. Ed Krupp.
5. “2012 Hoax” is a website written by several professional and amateur astronomers that thoroughly discusses the various doomsday scenarios and crackpot websites. You can also follow 20 12 2012 Hoax on Twitter.
7. If English isn’t your native language, astronomer Florian Freistetter has written several 2012 articles in German. They can be found on his website, Astrodicticum Simplex. Of special interest, Florian has recently put together a “2012 FAQ” page in German.
8. Daniel Fischer has a webpage in both English and German, Ist Es Wahr? Nachrichten vom Rande der Wirklichkeit (Is it true? News from the Edge of Reality), which tracks articles related to all sorts of doomsday and conspiracy theories.
