Universe Today

July 22, 2008December 29, 2015 by Fraser Cain

Carnival of Space #63

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Another new host for the Carnival of Space. This week, the whole carnival moves to the home of the Angry Astronomer.

Click here to read the Carnival of Space #63

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, let me know if you can be a host, and I’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

July 22, 2008December 24, 2015 by Astronomy Cast

Podcast: Quasars

Last week we talked about galaxies in general, and hinted at the most violent and energetic ones out there: active galaxies. Quasars have been a mystery for half a century; what kind of object could throw out more radiation than an entire galaxy? A black hole, it turns out, with the mass of hundreds of millions of suns performs this feat. Let’s trace back the history of quasars, how they were first discovered and puzzled astronomers for so long. And let’s look at what we know today.

Click here to download the episode

Quasars – Show notes and transcript

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

July 22, 2008December 24, 2015 by Mark Mortimer

Book Review: Floating to Space

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America’s OTHER space program is how John Powell bills his airship to orbit program. This endeavour, wonderfully encapsulated in his book Floating to Space, describes a less than typical application of a well-known technology. Using the concept of dynamic climbing, he believes and shows that airships are the better method to putting people and material into space.

Airships aren’t new. The Montgolfier brothers made the first modern edition and, since then, lighter-than-air transportation has been used to make determinations of weather in high latitudes, as well as to film sports events. Effectively, by trapping a less dense gas within an envelope, the envelope and a payload ascend. John Powell is fine tuning this concept for travelling into orbit and plans to soon elevate appreciable payloads to above 400 kilometres. And, as we all know, at that height, space travel becomes quite achievable.

Given this unconventional concept, Powell’s book follow the standard fare of all space dreamers. Like these, his book starts by admonishing the reader to accept physics and forgo tradition. Next, he justifies his beliefs by providing a review history. For example, did you know that the Nazca drawings might have been directed by a fellow in a hot air balloon? Continuing on, he provides a rational description of the current abilities of airships and their kin and ably convinces the reader that airships have got potential.

Now, if the reader perseveres through this brief background, they will get into the really exciting stuff. For it seems that John Powell is as much an engineer as he is a dreamer. Having amassed more than 80 missions over the previous 15 years, he can draw upon real experience and he does so in presenting the reader with steps he’s made of real progress. For example, during the early times he describes shooting rockets from balloons, nicknamed rockoons. Toward the end, he describes how he’s now floating platforms to above 100 000 feet. This story would warm any engineer’s heart. The technical progress described would set their hearts on fire.

Complementing the book is an enclosed DVD that is part documentary and part fanfare. In it, Powell’s placed some choice video taken from payloads as they climb to way-up-high and other videos that show a quite rapid descent from the same height. Equally exciting segments include footage of the next generation craft, Ascender 90, with ‘wings’ over 90 feet in length. It gently rises massively above a hanger floor as if coming to life for the first time. Given that this is a taste of things to come, this book is a wonderful place marker of what’s happened to date in Powell’s program and where things will hopefully be going.

In sum, this book’s got the touch of a visionary and the feel of a practitioner. It showcases a small cadre of people working against the grain of the norm. Yet, similarly, their goal is to achieve a great benefit for everyone. Optimism exudes from the pages as do technical triumphs. And, success just seems around the corner so that the reader may feel themselves getting drawn into the excitement and look to contribute.

Though not as flashy as rockets, airships provide similar capabilities. Both loft massive payloads up above the atmosphere. John Powell’s book Floating to Space â€“ The Airship to Orbit Program shows the feasibility of this endeavour as well as results of his own efforts. With time, it seems, this program is destined for a lofty future.

July 22, 2008December 24, 2015 by Tammy Plotner

Observing Alert: Dwarf Nova VY Aquari Re-Brightens

[/caption]According to AAVSO Special Notice #114 prepared by Matthew Templeton and released just a few minutes ago, dwarf nova VY Aquari is now rebrightening and observers are asked to contribute their data. VY Aquari has been fairly quiet since its last superoutburst of 10.2 magnitude on June 30, 2008 and is on the rise again…

“Several observers have reported that the dwarf nova VY Aqr (RA 21 12 09.20 Dec 08 49 36.5) has rebrightened since fading from its initial superoutburst. Although VY Aqr has been classified as a WZ Sge-type dwarf nova, previous superoutburst rebrightenings have not been well-observed. Continued monitoring of VY Aqr for the next several weeks is strongly encouraged. Both visual and CCD time-series observations are needed, the former to track the overall light curve, and the latter to study superhumps and short-term variability. Both positive and fainter-than estimates are valuable, so please continue to monitor VY Aqr if and when it becomes faint again — it may undergo further rebrightenings during this outburst.”

According to Sky & Telescope, a dwarf nova is a type of cataclysmic variable, consisting of a close binary star system in which one of the components is a white dwarf, which accretes matter from its companion. They are similar to classical novae in that the white dwarf is involved in periodic outbursts, but the mechanisms are different: classical novae result from the fusion and detonation of accreted hydrogen, while current theory suggests that dwarf novae result from instability in the accretion disk, when gas in the disk reaches a critical temperature that causes a change in viscosity, resulting in a collapse onto the white dwarf that releases large amounts of gravitational potential energy.

Dwarf novae are distinct from classical novae in other ways; their luminosity is lower, and they are typically recurrent on a scale from days to decades. The luminosity of the outburst increases with the recurrence interval as well as the orbital period; recent research with the Hubble space telescope suggests that the latter relationship could make dwarf novae useful standard candles for measuring cosmic distances.

Thanks to recent studies by R. E. Mennickent (et al): “The tomograms reveal complex emission structures that can be identified with the accretion disc, the bright spot and, in the case of VY Aqr, the secondary star. For the first time, the white dwarf is detected unambiguously in the spectrum of VY Aqr.”

Why not check it out yourself? If you have a GoTo telescope, set it on the coordinates listed above and compare what you see with the wide angle chart (courtesy of AAVSO), then up the magnification and compare the field with the Palomar Sky Survey plate image during minima. We’d love to hear about your experience!

July 22, 2008December 24, 2015 by Nancy Atkinson

Phoenix Lander Couldn’t Sleep At All Last Night

TEGA oven doors wide open. Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University

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For the first time, the Phoenix lander stayed up all night. But there was no partying for the little lander, just hard work. Phoenix coordinated its schedule to work together with the Mars Reconnaissance Orbiter to make joint observations to study Mars’ atmosphere. More on that in a minute, but the other big news from the Phoenix lander is that the doors to the Thermal and Evolved Gas Analyzer (TEGA) oven successfully opened, and the device is now ready to accept a sample of icy soil. If you remember, way back in the beginning of the mission, on about Sol 8, the first time the science team relayed orders for the spring-loaded oven doors to open, the doors only opened partially and the team had to vibrate the oven to get the soil inside. But this time, the 10 cm (4 inch) doors stands wide open, and today Phoenix will perfect its techniques to quickly get the icy soil sample inside the oven before the ice sublimates.

Now, about those atmospheric observations: Phoenix used its weather station, stereo camera and conductivity probe to monitor changes in the lower atmosphere and ground surface at the same time MRO studied the atmosphere and ground from above. The orbiter flew repeatedly over Phoenix’s location last evening, so it was good timing for a coordinated effort.

“We are looking for patterns of movement and phase change,” said Michael Hecht, lead scientist for Phoenix’s Microscopy, Electrochemistry and Conductivity Analyzer, which includes the lander’s fork-like thermal and conductivity probe. “The probe is working great. We see some changes in soil electrical properties, which may be related to water, but we’re still chewing on the data.”

The probe was inserted into the soil Sunday for more than 24 hours of measurements coordinated with the atmosphere observations. One goal is to watch for time-of-day changes such as whether some water alters from ice phase to vapor phase and enters the atmosphere from the soil.

The Phoenix team’s plans also include commanding the lander to conduct additional testing of the techniques for collecting a sample of icy soil. When the team is confident about the collecting method, it plans to use Phoenix’s robotic arm to deliver an icy sample to an oven of TEGA.

The team wants to make sure their techniques will quickly bring the soil into the oven, as it’s possible the oven will only work for one more test. The vibrating done to get the soil into the oven for the previous test caused a short circuit that may happen again the next time the oven is activated. The short could be fatal to the oven, but of course, we’re all still holding out hope for a better case scenario.

Original News Source: Phoenix News site

July 22, 2008December 24, 2015 by Nancy Atkinson

No Life Possible at Edges of the Pinwheel Galaxy

The bright red spots at the edge of the Pinwheel Galaxy means bad news for life. Image credit: NASA/JPL-Caltech/STScI

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Another beautiful image from the Spitzer Space Telescope; in this case, itâ€™s Messier 101, more commonly known as the Pinwheel Galaxy. But the pretty red highlights at the edges of the galaxy are bad news for anyone looking for evidence of life. “If you were going look for life in Messier 101, you would not want to look at its edges,” said Karl Gordon of the Space Telescope Science Institute. “The organics can’t survive in these regions, most likely because of high amounts of harsh radiation.” The red color highlights a zone where organic molecules called polycyclic aromatic hydrocarbons (PAHs), which are present throughout most of the galaxy, suddenly disappear.

PAHs are dusty, carbon-containing molecules found in star nurseries. They’re also found on Earth in barbeque pits, exhaust pipes and anywhere combustion reactions take place. Scientists believe this space dust has the potential to be converted into the stuff of life.

The Pinwheel galaxy is located about 27 million light-years away in the constellation Ursa Major. It has one of the highest known gradients of metals (elements heavier than helium) of all nearby galaxies in our universe. In other words, its concentrations of metals are highest at its center, and decline rapidly with distance from the center. This is because stars, which produce metals, are squeezed more tightly into the galaxy’s central quarters.

Gordon’s team also wanted to learn more about the gradient of the PAHs. Using Spitzer’s Infrared Array Camera and the Infrared Spectograph to carefully analyze the spectra of the PAHs, astronomers can more precisely identify the PAH features, and even deduce information about their chemistry and temperature. The astronomers found that, like the metals, the polycyclic aromatic hydrocarbons decrease in concentration toward the outer portion of the galaxy. But, unlike the metals, these organic molecules quickly drop off and are no longer detected at the very outer rim.

“There’s a threshold at the rim of this galaxy, where the organic material is getting destroyed,” said Gordon.

The findings also provide a better understanding of the conditions under which the very first stars and galaxies arose. In the early universe, there were not a lot of metals or PAHs around. The outskirt of the Pinwheel galaxy therefore serves as a close-up example of what the environment might look like in a distant galaxy.

In this image, infrared light with a wavelength of 3.6 microns is colored blue; 8-micron light is green; and 24-micron light is red. All three of Spitzer instruments were used in the study: the infrared array camera, the multiband imaging photometer and the infrared spectrograph.

Original News Source: JPL

July 22, 2008December 24, 2015 by Ian O'Neill

Large Chunk of ISS Space Junk Becomes Easy to Observe (Video)

The Easy Ammonia Servicer (EAS) photographed on July 23rd, 2007, by ISS astronauts. Watch your heads, it's re-entering tomorrow! (NASA)

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A huge piece of space debris, weighing 1400 lb (635 kg) and the size of two refrigerators, is gradually falling to Earth, giving observers on the ground a great opportunity to see it. The junk was jettisoned from the International Space Station (ISS) in 2007 and it is expected to re-enter the atmosphere later this year or early 2009. The Early Ammonia Servicer (EAS) was dropped from the ISS after a seven hour spacewalk and pushed in the opposite direction of the space station’s orbit shortly before a re-boost by a Soyuz resupply vehicle. This ensured the EAS would pose no danger to the ISS or crew on future orbits. Now the container is beginning its final few months in space and the bets are on as to where it will crash to Earth…

When the EAS, filled with ammonia coolant, had served its purpose the ISS crew had little choice but to throw it overboard. Astronaut Clay Anderson led the July 23rd 2007 operation with the assistance of cosmonauts Fyodor Yurchikhin and robotic arm operator Oleg Kotov as they shoved the EAS Earth-ward along with a 212 lb (96 kg) stanchion used to attach a camera to the station. The whole EVA lasted 7 hours and 41 minutes and the EAS was noted as the largest single piece of junk dropped from the ISS. At the time, mission control estimated that the EAS would orbit the Earth for 300 days; obviously this was a huge underestimate as it continues to spiral closer to the atmosphere one year after the mission.

The EAS is a huge piece of debris and easily tracked from the ground and poses no threat to missions, but it may be a hazard if, as expected, a large portion of the equipment survives re-entry. Dangers aside for now, the EAS is providing amateur astronomers with a new target to point their telescopes at. When the EAS was jettisoned, it was barely visible to the naked eye as it sped overhead with a magnitude of +4 to +4.5. Two days ago on July 20th, veteran satellite observer Marco Langbroek of Leiden, the Netherlands reported observing the EAS at an observable magnitude of +2.0. But it is moving very fast due to its decreased altitude.

Watch the EAS pass Altair in this high quality piece of video astronomy by Kevin Fetter (July 15th, 2008) »

Currently, the EAS can be seen over Europe, and next week North America will be able to spot it. For information on where and when to look for a chance to observe this huge lump of waste from the ISS, check out SpaceWeather.com’s Simple Satellite Tracker before it starts to flirt with our upper atmosphere in the next few months.

Sources: Space Weather, NASA, Collect Space.

July 21, 2008December 24, 2015 by Ian O'Neill

The Cosmic Void: Could we be in the Middle of it?

Is our region of space unique? As in there isn't much here? Credit: ESO. Edit: Ian O'Neill

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On large scales, the Universe is homogeneous and isotropic. This means that no matter where you are located in the cosmos, give or take the occasional nebula or galactic cluster, the night sky will appear approximately the same. Naturally there is some ‘clumpiness’ in the distribution of the stars and galaxies, but generally the density of any given location will be the same as a location hundreds of light years away. This assumption is known as the Copernican Principle. By invoking the Copernican Principle, astronomers have predicted the existence of the elusive dark energy, accelerating the galaxies away from one another, thus expanding the Universe. But say if this basic assumption is incorrect? What if our region of the Universe is unique in that we are sitting in in a location where the average density is a lot lower than other regions of space? Suddenly our observations of light from Type 1a supernovae are not anomalous and can be explained by the local void. If this were to be the case, dark energy (or any other exotic substance for that matter) wouldn’t be required to explain the nature of our Universe after all…

Dark energy is a hypothetical energy predicted to permeate through the Cosmos, causing the observed expansion of the Universe. This strange energy is believed to account for 73% of the total mass-energy (i.e. E=mc²) of the Universe. But where is the evidence for dark energy? One of the main tools when measuring the accelerated expansion of the Universe is to analyse the red-shift of a distant object with a known brightness. In a Universe filled with stars, what object generates a “standard” brightness?

The progenitor of a Type Ia Supernova. Credit: NASA, ESA, and A. Field (STScI)

Type 1a supernovae are known as ‘standard candles’ for this very reason. No matter where they explode in the observable universe, they will always blow with the same amount of energy. So, in the mid-1990’s astronomers observed distant Type 1a’s a little dimmer than expected. With the basic assumption (it may be an accepted view, but it is an assumption all the same) that the Universe obeys the Copernican Principle, this dimming suggested that there was some force in the Universe causing not only an expansion, but an accelerated expansion of the Universe. This mystery force was dubbed dark energy and it is now a commonly held view that the cosmos must be filled with it to explain these observations. (There are many other factors explaining the existence of dark energy, but this is a critical factor.)

According to a new publication headed by Timothy Clifton, from the University of Oxford, UK, the controversial suggestion that the widely accepted Copernican Principle is wrong is investigated. Perhaps we do exist in a unique region of space where the average density is much lower than the rest of the Universe. The observations of distant supernovae suddenly wouldn’t require dark energy to explain the nature of the expanding Universe. No exotic substances, no modifications to gravity and no extra dimensions required.

Clifton explains conditions that could explain supernova observations are that we live in an extremely rarefied region, right near the centre, and this void could be on a scale of the same order of magnitude as the observable Universe. If this were the case, the geometry of space-time would be different, influencing the passage of light in a different way than we’d expect. What’s more, he even goes as far as saying that any given observer has a high probability of finding themselves in such a location. However, in an inflationary Universe such as ours, the likelihood of the generation of such a void is low, but should be considered nonetheless. Finding ourselves in the middle of a unique region of space would out rightly violate the Copernican Principle and would have massive implications on all facets of cosmology. Quite literally, it would be a revolution.

The Copernican Principle is an assumption that forms the bedrock of cosmology. As pointed out by Amanda Gefter at New Scientist, this assumption should be open to scrutiny. After all, good science should not be akin to religion where an assumption (or belief) becomes unquestionable. Although Clifton’s study is speculative for now, it does pose some interesting questions about our understanding of the Universe and whether we are willing to test our fundamental ideas.

Sources: arXiv:0807.1443v1 [astro-ph], New Scientist Blog

July 21, 2008December 24, 2015 by Nancy Atkinson

NASA to Develop GPS-Like System for the Moon

Future astronauts may use GPS-like system. Credit: The Ohio State University

During the second moonwalk of the Apollo 14 mission, Alan Shepard and Edgar Mitchell were hoping to walk to the 300 meter (1,000 feet) wide Cone Crater on the moon, not far from their landing site. However, the two astronauts were not able to find the crater’s rim amid the rolling, repetitive terrain. Later analysis using pictures the two astronauts took determined they had come within 65 feet of the crater. People are used to having certain visual cues to judge distances, such as the size of a building or another car on the horizon, said Ron Li, who has been awarded a $1.2 million grant to develop a navigation system to be used on the moon. Since the moon has no landmarks or cues to help determine distance, getting lost, or misjudging a distant object’s size and location would be easy, and extremely dangerous. New technology like sensors, inertial navigation systems, cameras, computer processors, and image processors will make the next trip to the moon easier for astronauts.

Li, from The Ohio State University, developed software for the Mars rovers Spirit and Opportunity, which has helped him learn a lot about navigation. The navigation system to help future astronauts find their way around moon won’t use satellites; instead the system will rely on signals from a set of sensors including lunar beacons, stereo cameras, and orbital imaging sensors.

Images taken from orbit will be combined with images from the surface to create maps of lunar terrain. Motion sensors on lunar vehicles and on the astronauts themselves will allow computers to calculate their locations. Signals from lunar beacons, the lunar lander, and base stations will give astronauts a picture of their surroundings similar to what drivers see when using a GPS device on Earth. The researchers have named the entire system the Lunar Astronaut Spatial Orientation and Information System (LASOIS).

Astronauts will have a keypad and screen, possibly right on their spacesuits, to view their location and search for new destinations.

Keeping astronauts safe will be a top priority for Li’s team, which includes experts in psychology and human-computer interaction as well as engineering.

“We will help with navigation, but also with astronauts’ health as well,” Li said. “We want them to avoid the stress of getting lost, or getting frustrated with the equipment. Lunar navigation isn’t just a technology problem, it’s also biomedical.”

News Source: The Ohio State University

July 21, 2008December 24, 2015 by Ian O'Neill

Successful Test Firing of Orion Jettison Motor (Video)

Successful test-firing of Orion's jettison engines (Aerojet)

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It looks like the hardware is gradually slotting into place for the development of the Orion capsule in NASA’s Constellation Program. On July 17th, the ultimate “ejection seat” was tested by NASA and rocket contractor Aerojet: The Orion jettison motor. Should there be an emergency during Ares rocket/Orion capsule during launch, the Orion capsule will have the capability to eject (whether it is on the launchpad or travelling through the atmosphere), ensuring the safety of the crew. This is the first safety measure of its kind, so a successful engine test can only help to boost confidence in the technology behind Orion…

Although there are concerns for the Constellation Program funding and technology-wise, there is good news coming from the development of NASA’s new Orion crew module. The first full-scale test firing of the jettison motor was successful, boosting confidence in the new safety system the capsule will have installed. Later this year, a full-scale “Pad Abort-1” test is scheduled in the New Mexico desert, where a mock Orion will be blasted clear of a model launchpad (up to a mile in altitude) to test the effectiveness of the system. Tests are already under way to deduce whether a dry or wet touch-down will be carried out by the Orion capsule using cadavers (human corpses) as crash-test dummies.

The jettison motor was tested at the Astrojet facility in Sacramento, California, which marks the start of a series of developmental tests before the finished article is integrated into the mock Orion module to begin the New Mexico tests. During last weeks test firing, engineers were testing acoustic, vibration and shock effects on the engines. It appears everything ran smoothly, indicating the jettison system is close to system-level demonstration.

View the test-firing on the Constellation Project site »

This is a critical stage in the development of Orion. Since the Columbia disaster in 2003, NASA has felt pressure to ensure the safety of their astronauts. Although strict guidelines are in place, space travel remains a risky business where tough decisions need to be made. Installing an Orion jettison system will be a huge piece of mind for mission controllers and Constellation astronauts should there be launch complications on the pad or as Ares powers through the atmosphere.

Source: NASA