Kick back and watch the clouds go by — on Mars! Emily Lakdawalla at the Planetary Society Blog has put together a very nifty video from Mars Express data, showing clouds in motion over Mars. Emily has just learned a new technique called ‘tweening’ to create smooth animation videos from a series of images that are not at a very high frame rate. She explains more about the technique on her blog post here and has promised a two-part “how to” explainer for those interested in learning how to do this for yourself.
The cloudy area shown on Mars is within Noachis Terra to the west of Hellas basin, around 45 degrees south, 38 east.
Artists concept of the James Webb Space Telescope in space. Credit: NASA
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Under the threat of cancellation because of cost overruns, this is about the worst news the James Webb Space Telescope could get. A report in Aviation Week & Space Technology says the life cycle costs for developing, launching and managing a five-year mission for the giant space telescope has risen to $8.7 billion, up from the previous estimate of $6.5 billion.
This past July, the U.S House of Representatives’ appropriations committee on Commerce, Justice, and Science proposed a budget for fiscal year 2012 that would cancel JWST’s funding. No final decision has been made on the fate of JWST, but this latest increase – just one of many life cycle increases of the telescope – does not bode well for NASA’s successor to the Hubble Space Telescope.
Aviation Week said managers at NASA have been re-planning the James Webb Space Telescope program after an independent cost analysis found it over budget and behind schedule. The independent analysis was headed by John Casani, a special assistant to the director of the Jet Propulsion Laboratory with long experience developing scientific spacecraft, and that report found the $5.1 billion estimate to completion was at least $1.4 billion short.
Now, tack on an additional $2.2 billion.
No details were provided of what the $2.2 billion includes, but the launch of JWST would be no earlier than 2018.
Details of how the agency will pay the cost will be covered in the fiscal 2013 NASA budget request now in preparation, Aviation Week quoted a NASA spokesman.
Of course, NASA’s entire budget is threatened to be cut by at least 10%, as President Obama has asked federal agencies to cut their budgets by that amount to enable a chance at balancing the federal budget.
But today, Nature News reports that NASA is looking at funding the flagship observatory in a different manner. JWST is currently funded entirely through NASA’s science division; now NASA is requesting that more than $1 billion in extra costs be shared 50:50 with the rest of the agency. Nature News said the request reflects administrator Charles Bolden’s view, expressed earlier this month, that the telescope is a priority not only for the science program but for the entire agency.
If ‘creative’ funding for JWST is not worked out, it would mean other programs would suffer greatly or be cut.
NASA made personnel changes at Goddard Spaceflight Center, the home of JWST, after Casani’s group concluded the majority of costs overruns were managerial rather than technical.
Sources: Aviation Week & Space Technology, Nature News
The variations in brightness can be interpreted as vibrations, or oscillations within the stars, using a technique called asteroseismology. The oscillations reveal information about the internal structure of the stars, in much the same way that seismologists use earthquakes to probe the Earth's interior. Credit: Kepler Astroseismology team.
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Asteroseismology is a relatively new field in astronomy. This branch uses sound waves in stars to explore their nature in the same way seismologists on Earth have used waves induced by tectonic activity to probe the interior of our planet. These waves aren’t heard directly, but as they strike the surface they can cause it to undulate, shifting the spectral lines this way and that, or compress the outer layers causing them to brighten and fade which can be detected with photometry. By studying these variations, astronomers have begun peering into stars. This much is generally known, but some of the specific tricks aren’t often brought up when discussing the topic. So here’s five things you can do with asteroseismology you may not have known about!
1. Determine the Age of a Star
From high school science you should know sound will travel through a medium at a characteristic speed for a given temperature and pressure. This information tells you something about the chemical composition of the star. This is a fantastic thing since astronomers can then check that against predictions made by stellar models. But astronomers can also take that one step further. Since the core of a star slowly converts hydrogen to helium over its lifetime, that composition will change. How much it has changed from its original composition towards the point where there’s no longer enough hydrogen to support fusion, tells you how far through the main sequence lifetime a star is. Since we know the age of the solar system very well from meteorites, astronomers have calibrated this technique and begun using it on other stars like α Centauri. Spectroscopically, this star is expected to be nearly identical to the Sun; it has very similar spectral type and chemical composition. Yet a 2005 study using this technique pinned α Cen as 6.7 ± 0.5 billion years which is about one and a half billion years older than the Sun. Obviously, this still has a rather large uncertainty to it (nearly 10%), but the technique is still new and will certainly be refined in the future.
And if that wasn’t cool enough by itself, astronomers are now beginning to use this technique on stars with known planets to get a better understanding of the planets! This can be important in many cases since planets will initially glow more brightly in younger systems since they still retain heat from their formation and this amount of extra light could confuse astronomers on just how might light is being reflected leading to inaccurate estimates of other properties like size or reflectivity.
2. Determine Internal Rotation
Cover of a Book on the Solar Tachocline showing abrupt transition discovered by helioseismology
We already know that stars rotation is a bit funny. They rotate faster at their equator than at their poles, a phenomenon known as differential rotation. But stars are also expected to have differences in rotation as you get deeper. For stars like the Sun, this effect is related to a difference in energy transport mechanisms: radiative, where energy is conducted by a flow of photons in the deep interior, to convective, where energy is carried by bulk flow of matter, creating the boiling motion we see on the surface. At this boundary, the physical parameters of the system change and the material will flow differentially. This boundary is known as the tachocline. Within the Sun, we’ve known it’s there, but using asteroseismology (which, when used on the Sun is known as helioseismology), astronomers actually pinned it down. It’s 72% the way out from the core.
3. Find Planets
Until very recently, the most reliable way to find planets has been to look for the spectroscopic wiggle as the planets tug the star around. This technique sounds very straightforward, and it can be, unless the star has a lot of wiggle of its own due to the effects that make asteroseismology possible. Those effects can easily be much larger than those created by planets. So if you want to find planets lost in the forest of noise, you’d best understand the effects caused by the pulsating stellar surface. After astronomers cancelled out those effects on V391 Pegasi, they discovered a planet. And what a weird one it was. This planet is orbiting a sub-dwarf star, which is the helium core of a post-main sequence star which has ejected its hydrogen envelope. Of course, this occurs during the red giant phase when the star should have swollen up to engulf the gas giant planet in orbit. But apparently the planet survived, or somehow came along later.
4. Find Buried Sunspots
Turning to recent news, helioseismology recently found some sunspots. This wouldn’t be a big deal. Anyone with a properly filtered telescope can find them. Except these ones were buried some 60,000 km beneath the Sun’s surface. By using the seismic data, astronomers found an overdense region beneath the surface. This region was caused, just as sunspots are, by a tangle in the magnetic field keeping the material in place. As it rose to the surface, it became a sunspot. Here’s the vid:
5. Make “Music”
Because many of the events that create the soundwaves in stars are periodic, they are rhythmic in nature. This has prompted many explorations into using these naturally created beats to make music. A direct example is this one which simply assigns tones to the modes of pulsation. The site also notes that the beat created by one of the stars, has been used as a base for club music in Belgium. This has also been done for longer “symphonies” by Zoltan Kollath.
A stunning look at Jupiter in the night sky, from under a canopy of trees. “I took that exposure in Woodbury, CT on August 12, 2011 around 1:00 a,m.,” said photographer Matt Childs. “It is a combination of a couple different shots that I stacked together much like an HDR process. The camera I used was a Canon Rebel Xsi along with a 50mm lens. My observing locations are heavy with trees so its not uncommon for me to find ‘windows’ between branches or leaves that enable me to take a peek into the cosmos.”
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
Example Of LIVE Image From Bareket Observatory - Viewer Located Inside This Article
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Are you ready for some excitement? How would you like to watch a LIVE broadcast of Comet C2009 P1 Garradd right here on Universe Today?! Thanks to our good friends at Bareket Observatory and clear skies in Israel, we can do just that! Step inside to our virtual observatory…
Before you get upset and think there’s something wrong, there are a few things you must remember about watching a live telescope broadcast. If there are clouds – you will see no image. If the camera isn’t turned on and broadcasting – you will only see the blue “frame” below where the image is meant to be. Because the data load is so huge from the incoming images, it limits itself to refreshing about every 30 to 60 seconds. This means the image will appear static, then reset itself. If you watch for a period of perhaps 10 minutes or so, you will notice appreciable movement against the background stars. The tracking is set on the nucleus of the comet, so the comet won’t appear to move – the background stars will each time it refreshes. There can also be unforeseen glitches, (such as viewer overload) so please be patient! Last… There will be no image until the broadcast time. You don’t have to click anywhere else – when the broadcast is happening it will be right here where you see the frame below.
The live broadcast of Comet Garradd will take place on Monday, August 22 – 2100-0300 local Israel time (UTC+3). To give you some help figuring times, here’s a very brief listing that’s in absolutely no particular order:
Shanghai – Tue 2:00 AM – Tue 8:00 AM
Sydney – Tue 4:00 AM – Tue 10:00 AM
Zurich – Mon 8:00 PM – Tue 2:00 AM
Moscow – Mon 10:00 PM – Tue 4:00 AM
Rome – Mon 8:00 PM – Tue 2:00 AM
London – Mon 7:00 PM – Tue 1:00 AM
New York – Mon 2:00 PM – Mon 8:00 PM
Mexico City – Mon 1:00 PM – Mon 7:00 PM
Vancouver – Mon 11:00 AM – Mon 5:00 PM
Honolulu – Mon 8:00 AM – Mon 2:00 PM
New Delhi – Mon 11:30 PM – Tue 5:30 AM
Johannesburg – Mon 8:00 PM – Tue 2:00 AM
Tokyo – Tue 3:00 AM – Tue 9:00 AM
Denver – Mon 12:00 Noon – Mon 6:00 PM
San Francisco – Mon 11:00 AM – Mon 5:00 PM
San Juan – Mon 2:00 PM – Mon 8:00 PM
Anchorage – Mon 10:00 AM – Mon 4:00 PM
That having been said, the frame right below these words will be your virtual eyepiece!
Feel free to “take” any images you want and stitch together a video – or post ’em to your favorites sites. If you enjoyed the broadcast, won’t you take a few minutes and thank the hardworking, generous crew at Bareket Observatory? I am very sure they would appreciate it!
A halo around the Sun, as see on the island of Lanzarote in the Canary Islands. Credit: 'Astrohans'
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A beautiful and colorful halo — a 22 degree ring — as seen on the island of Lanzarote in the Canary Islands, taken by ‘Astrohans” (a.k.a. Hans Schremmer) on Flickr. Hans posted that circumhorizontal arc is also visible, and that the photo was taken on May 8, 2010 in Playa Blanca, using a Canon EOS 400D Digital.
Halos form when light from the Sun or Moon is refracted by ice crystals associated with thin, high-level clouds (like cirrostratus clouds). A 22 degree halo is a ring of light 22 degrees from the Sun (or Moon) and is the most common type of halo observed.
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
Seattle, January, 2003. Two prestigious astronomers: Puragra GuhaThakurta of UCSC and David Reitzel of UCLA present some new findings to the American Astronomical Society that would seem to indicate that large spiral galaxies grow by gobbling up smaller satellite galaxies. Their evidence, a faint trail of stars in the nearby Andromeda galaxy that are thought to be a vast trail of debris left over from an ancient merger of Andromeda with another, smaller galaxy. This process, known as Galactic Cannibalism is a process whereby a large galaxy, through tidal gravitational interactions with a companion galaxy, merges with that companion, resulting in a larger galaxy.
The most common result of this process is an irregular galaxy of one form or another, although elliptical galaxies may also result. Several examples of this have been observed with the help of the Hubble telescope, which include the Whirlpool Galaxy, the Mice Galaxies, and the Antennae Galaxies, all of which appear to be in one phase or another of merging and cannibalising. However, this process is not to be confused with Galactic Collision which is a similar process where galaxies collide, but retain much of their original shape. In these cases, a smaller degree of momentum or a considerable discrepancy in the size of the two galaxies is responsible. In the former case, the galaxies cease moving after merging because they have no more momentum to spare; in the latter, the larger galaxies shape overtakes the smaller one and their appears to be little in the way of change.
All of this is consistent with the most current, hierarchical models of galaxy formation used by NASA, other space agencies and astronomers. In this model, galaxies are believed to grow by ingesting smaller, dwarf galaxies and the minihalos of dark matter that envelop them. In the process, some of these dwarf galaxies are shredded by the gravitational tidal forces when they travel too close to the center of the “host” galaxy’s enormous halo. This, in turn, leaves streams of stars behind, relics of the original event and one of the main pieces of evidence for this theory. It has also been suggested that galactic cannibalism is currently occurring between the Milky Way and the Large and Small Magellanic Clouds that exist beyond its borders. Streams of gravitationally-attracted hydrogen arcing from these dwarf galaxies to the Milky Way is taken as evidence for this theory.
As interesting as all of these finds are, they don’t exactly bode well for those of us who call the Milky Way galaxy, or any other galaxy for that matter, home! Given our proximity to the Andromeda Galaxy and its size – the largest galaxy of the Local Group, boasting over a trillion stars to our measly half a trillion – it is likely that our galaxy will someday collide with it. Given the sheer scale of the tidal gravitational forces involved, this process could prove disastrous for any and all life forms and planets that are currently occupy it!
The nature of the highly compressed matter that makes up neutron stars has been the subject of much speculation. For example, it’s been suggested that under extreme gravitational compression the neutrons may collapse into quark matter composed of just strange quarks – which suggests that you should start calling a particularly massive neutron star, a strange star.
However, an alternate model suggests that within massive neutron stars – rather than the neutrons collapsing into more fundamental particles, they might just be packed more tightly together by adopting a cubic shape. This might allow such cubic neutrons to be packed into about 75% of the volume that spherical neutrons would normally occupy.
Some rethinking about the internal structure of neutron stars has been driven by the 2010 discovery that the neutron star PSR J1614–2230, has a mass of nearly two solar masses – which is a lot for a neutron star that probably has a diameter of less than 20 kilometres.
PSR J1614–2230, described by some as a ‘superheavy’ neutron star, might seem an ideal candidate for the formation of quark matter – or some other exotic transformation – resulting from the extreme compression of neutron star material. However, calculations suggest that such a significant rearrangement of matter would shrink the star’s volume down to less than the Schwarzschild radius for two solar masses – meaning that PSR J1614–2230 should immediately form a black hole.
But nope, PSR J1614–2230 is there for all to observe, a superheavy neutron star, which is hence almost certainly composed of nothing more exotic that neutrons throughout, as well as a surface layer of more conventional atomic matter.
Modelling the quantum field waveforms of neutrons under increasing densities suggests a cubic, rather than a spherical, geometry is more likely. Credit: Llanes-Estrada and Navarro.
Nonetheless, stellar-sized black holes can and do form from neutron stars. For example, if a neutron star in a binary system continues drawing mass of its companion star it will eventually reach the Tolman–Oppenheimer–Volkoff limit. This is the ultimate mass limit for neutron stars – similar in concept to the Chandrasekhar limit for white dwarf stars. Once a white dwarf reaches the Chandrasekhar limit of 1.4 solar masses it detonates as a Type 1a supernova. Once, a neutron star reaches the Tolman–Oppenheimer–Volkoff mass limit, it becomes a black hole.
Due to our current limited understanding of neutron star physics, no-one is quite sure what the Tolman–Oppenheimer–Volkoff mass limit is, but it is thought to lie somewhere between 1.5 – 3.0 solar masses.
So, PSR J1614–2230 seems likely to be close to this neutron star mass limit, even though it is still composed of neutrons. But there must be some method whereby a neutron star’s mass can be compressed into a smaller volume, otherwise it could never form a black hole. So, there should be some intermediary state whereby a neutron star’s neutrons become progressively compressed into a smaller volume until the Schwarzschild radius for its mass is reached.
Llanes-Estrada and Navarro propose that this problem could be solved if, under extreme gravitational pressure, the neutrons’ geometry became deformed into smaller cubic shapes to allow tighter packing, although the particles still remain as neutrons.
So if it turns out that the universe does not contain strange stars after all, having cubic neutron stars instead would still be agreeably unusual.
Further reading: Llanes-Estrada and Navarro. Cubic neutrons.
Moon Occults Triple star Pi Sagitarii. Credit: Efrain Morales Rivera, Jaicoa Observatory
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On August 10, the Moon passed in front of the triple star system, Pi Sagitaurii star system. The even was captured by Efrain Morales Rivera from the Jaicoa Observatory in Aguadilla, Puerto Rico. “An interesting event, capturing this triple star system being occulted by the Moon and 1 hour and 26 minutes later re-appearing on the bright side of the moon,” Rivera wrote to tell us.
He even created an animation of the stars “winking out,” as seen below.
Closeup animation of Moon occulting the Pi Sagitaurii star system, Credit: Efrain Morales Rivera, Jaicoa Observatory
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