Universe Today

January 16, 2008December 26, 2015 by Ian O'Neill

Sea Launch Rocket Success

After a year of silence, Sea Launch Co. is back in business, inserting a telecommunications satellite into orbit on January 15th. Almost a year ago, a Russian-Ukrainian built Zenit 3SL rocket, launching from the sea-based platform Odyssey, exploded, causing Sea Launch to halt business for the rest of 2007. On Tuesday the company could breath a sigh of relief as they saw the Zenit’s boosters light up the night sky…

It must have been a tough year for Sea Launch after the destruction of one of their rockets, loss of its payload (NSS-8, a Dutch telecommunications satellite) and damage to the launch platform, Odyssey. Sea Launch, a company specializing in commercial launches from a mobile launch pad, spent the last year making repairs to Odyssey (a converted oil rig) so five planned missions could go ahead as scheduled in 2008. The first was a resounding success and all going well, the accident last year wont put a dent in business for the future.

Sea Launch is currently the only sea-based launch company in the world. Launching rockets from a mobile launch platform has many advantages including:

Equatorial positioning – rockets launched at or near the equator provides a little extra “push” from the rotational velocity of the Earth, saving on energy required to reach orbit (saving fuel and therefore cost).
Safe location – away from populated areas, surrounded by water.
Flexible location – not restricted to a site prone to storms or geological instabilities.

There can be some drawbacks with sea-based launches. A launch planned in November 2007 had to be cancelled due to unusually strong ocean currents in the mid-Pacific launch site, so there can be some logistic issues when factoring in not only weather conditions but also ocean conditions. However, this week’s successful launch overcame the troubles of last year’s accident and managed to find calm conditions to send a Thuraya satellite (built by Boeing Satellite Systems International in El Segundo, California) into geosynchronous orbit and improve mobile communication coverage over Asia.

Source: Sea Launch, Space.com

January 16, 2008January 24, 2021 by Fraser Cain

Astrosphere for January 16, 2008

I know it’s been a bit of a delay, but I do really enjoy crawling through the interwebs, finding spacey stories. Your photo for the day is M42, captured by tegwilym.

What did I find today?

I reported on MESSENGER’s Mercury flyby, but the Planetary Society’s Emily Lakdawalla always has the best coverage of these planetary visitations.

While I was writing like a maniac at the American Astronomical Society meeting, rarely leaving the press room to feel the warm Austin air, Pamela was out and about, meeting, greeting and recording audio chats. Here’s one with the folks from the Galaxy Zoo.

Pharyngula won best science blog for 2007. And that means Phil didn’t. Uh, oh, nobody tell him.

Phil won’t notice, he’s too busy watching old YouTube video of Shatner singing Rocket Man. Yikes!

Larry Sessions at Earth & Sky Blogs shows you how to measure the Sun.

And finally, Wired Science is reporting that space is a top question posed to presidential candidates. How do you feel about space exploration?

January 16, 2008December 26, 2015 by Nancy Houser

Astronomers Could Detect Oceans on Extrasolar Planets

Imagine if astronomers could tell the difference between Earth-like extrasolar planets just by seeing the reflected light from their oceans? That sounds like science fiction, but a team of researchers have proposed that it’s really possible to detect the shape of the light curve glinting off an extrasolar planet and know if it has oceans.

This ground-breaking (water splashing?) idea was written in a recent journal article by D.M. Williams and E. Gaidos, entitled Detecting the Glint of Starlight on the Oceans of Distant Planets published January, 2008 in the Arxiv prepress e-Print archive.

The article describes the methods astronomers could use to detect the glint, or water reflection, from the “disk-averaged signal of an Earth-like planet in crescent phase.” They used the Earth as an example, and generated a series of light curves for a planet with our orientation and axial tilt.

They calculated that planets partially covered by water should appear much brighter when they’re near the crescent phase because light from the parent star reflects off the oceans very efficiently at just the right angles. By watching an extrasolar planet move through its orbit, its light curve should give off the telltale signature that there are oceans present.

According to their calculations, this method should work for about 50% of the visible planets. Furthermore, it should be possible to measure the ratio of land to water, and even get a sense of continents.

In order to test their theories, they’re planning to use remote observations of Earth, using interplanetary spacecraft. This will demonstrate if Earth can be observed at extreme phase anglesâ€”orbiting spacecraft around or on route to Mars.

And then the upcoming planet hunting missions, such as Darwin and the Terrestrial Planet Finder (if it ever gets completed) should be able to make the direct analysis of Earth-sized worlds orbiting other stars. Just by measuring the brightness, they should know if there are oceans, boosting the prospects for life.

Original Source: Arxiv

January 16, 2008December 26, 2015 by Fraser Cain

Nobody Has Ever Seen This Side of Mercury

Even though spacecraft have visited Mercury in the past, the same hemisphere was always in sunlight for every encounter. One side was photographed, and the other side was a complete and total mystery. There could be a big smiley face there, and we’d never know it. Well, the mystery’s over. MESSENGER flew past Mercury on January 14th, 2008, and revealed the planet’s hidden side… mostly.

Mariner 10 was the first spacecraft to zip past the planet Mercury, making three flybys in 1974 and 1975. Because the same hemisphere was in sunlight, the spacecraft was only able to image half the planet.

On January 14th, 2008, NASA’s MESSENGER spacecraft captured this image of Mercury when it was about 27,000 km (17,000 miles) away from the planet. During this flyby, it filled in about half of the hemisphere missed by Mariner 10. So that means that there are still some parts hidden – waiting to be revealed in future flybys.

And so, did it see a smiley face? Nope. The hidden hemisphere was pretty much like the rest of Mercury revealed so far: craters, ridges, bright and dark regions. At the upper right is the giant Caloris basin; its western regions haven’t been seen by spacecraft before.

If you’re hoping for more photos, don’t worry. This is just a quick black-and-white image captured by MESSENGER. NASA is planning to release more detailed images, including colour photographs over the next few days, so stay tuned.

We’ll keep posting them as they’re released.

Original Source: MESSENGER News Release

January 16, 2008December 26, 2015 by Nancy Atkinson

Ice Clouds on Mars Create Shade

Until now, Mars has generally been regarded as a desert world, where a visiting astronaut would be surprised to see clouds drifting across the orange sky. But new data and images show that Mars does indeed have clouds, and some are actually thick enough to cast a shadow on the planet’s surface. These are clouds of dry ice, or carbon dioxide (CO2), and sometimes they are so large and so dense that they throw quite dark shadows on the dusty surface. This, in turn, can affect the weather patterns on Mars. Researchers also say this discovery could help to understand Mars’ climate history.

Data obtained from ESA’s Mars Express OMEGA Visible and Infrared Mineralogical Mapping Spectrometer instrument has been analyzed by a group of French scientists.

“This is the first time that carbon dioxide ice clouds on Mars have been imaged and identified from above,” said Franck Montmessin of the Service da Aeronomie, University of Versailles. “This is important because the images tell us not only about their shape, but also their size and density.”

Clouds of water ice particles have previously been seen, for example on the sides of the giant Martian volcanoes. There have also been hints of much higher, wispy clouds made up of carbon dioxide (CO2) ice crystals. This is not too surprising, since the thin Martian atmosphere is mostly made of carbon dioxide, and temperatures on the fourth planet from the Sun often plunge well below the â€˜freezing pointâ€™ of carbon dioxide. But these clouds are not very thick.

But the CO2 clouds detected by OMEGA are very different. Not only are they surprisingly high — more than 80 km above the surface — but they can be several hundred kilometers across. They are also much thicker than expected. Instead of looking like the wispy ice clouds seen on Earth, they resemble tall convectional clouds that grow as the result of rising columns of warm air.

Even more surprising is the fact that the CO2 ice clouds are made of quite large particles – more than a micron (one thousandth of a millimeter) across — and they are sufficiently dense to noticeably dim the Sun. Normally, particles of this size would not be expected to form in the upper atmosphere or to stay aloft for very long before falling back towards the surface.

“The clouds imaged by OMEGA can reduce the Sun’s apparent brightness by up to 40 per cent,” said Montmessin. “This means that they cast quite a dense shadow and this has a noticeable effect on the local ground temperature. Temperatures in the shadow can be up to 10 degrees C cooler than their surroundings, and this in turn modifies the local weather, particularly the winds.”

Since the CO2 clouds are mostly seen in equatorial regions, the OMEGA team believes that the unexpected shape of the clouds and large size of their ice crystals can be explained by the extreme variations in daily temperature that occur near the equator.

“The cold temperatures at night and relatively high day-time temperatures cause large diurnal waves in the atmosphere,” explained Montmessin. “This means there is a potential for large-scale convection, particularly as the morning Sun warms the ground.”

“This discovery is important when we come to consider the past climate of Mars,” Montmessin continued. “The planet seems to have been much warmer billions of years ago, and one theory suggests that Mars was then blanketed with CO2 clouds. We can use our studies of present-day conditions to understand the role that such high level clouds could have played in the global warming of Mars.”

Original News Source: ESA Press Release

January 16, 2008December 26, 2015 by Nancy Atkinson

Study Shows More Antarctic Ice Loss

Increasing amounts of ice mass have been lost from West Antarctica and the Antarctic peninsula over the past ten years, according to a 10-year study from the University of Bristol, England. But at the same time, however, the ice mass in East Antarctica has been roughly stable, with neither loss nor accumulation over the past decade.

Professor Jonathan Bamber at the University of Bristol and colleagues estimated a loss of 132 billion tons of ice in 2006 from West Antarctica “up from about 83 billion tons in 1996” and a loss of about 60 billion tons in 2006 from the Antarctic Peninsula.

“To put these figures into perspective,” Bamber said, “four billion tons of ice is enough to provide drinking water for the whole of the UK population for one year.”

The data comes from satellite imagery that cover 85% of Antarctica’s coastline, which the researchers compared with simulations of snow accumulation over the same period, using a regional climate model.

“Over the 10 year time period of the survey, the ice sheet as a whole was certainly losing mass,” said Bamber, “and the mass loss increased by 75% during this time. Most of the mass loss is from the Amundsen Sea sector of West Antarctica and the northern tip of the Peninsula where it is driven by ongoing, pronounced glacier acceleration.”

In East Antarctica, the mass balance, which accounts for addition to the ice sheet due to snowfall and the subtraction of ice due to changes in the glacier, is near zero. But the thinning of its potentially vulnerable marine sectors suggests this may change in the near future.

As to the differences in the West and East Antarctic ice sheets, Bamber said, â€œThe West Antarctic Ice Sheet is a “marine based” ice sheet resting on bedrock below sea level with bed slopes inclined downward inland. It has been suggested that this makes the WAIS more susceptible to change caused by the ocean than the East Antarctic Ice Sheet.”

The study conclude that the Antarctic ice sheet mass budget is more complex than indicated by the evolution of its surface mass balance or climate-driven predictions.

Changes in glacier dynamics are significant and may in fact dominate the ice sheet mass budget. This conclusion is contrary to model simulations of the response of the ice sheet to future climate change, which conclude that it will grow due to increased snowfall.

Satellite data was obtained from ERS-1, ERS-2, RADARSAT and ALOS.

Original News Source: University of Bristol Press Release

January 16, 2008December 26, 2015 by Nancy Atkinson

NASA Wants Your Opinion on the Lunar Lander

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NASA’s Constellation Program has released an announcement that they are looking for people to evaluate the design of the Altair spacecraft that will land on the moon. So if you work in the science community or in a related industry, NASA wants your opinion. What they are looking for are evaluations of the current developmental concept for the Altair lander and the safety improvements that have been proposed, as well as recommendations for industry-government partnerships.

“By soliciting ideas and suggestions from industry and the science community, NASA hopes to foster a collaborative environment during this early design effort,” said Jeff Hanley, the Constellation Program manager. “Such collaboration will support the development of a safe, reliable and technologically sound vehicle for our crews.”

All you have to do is write a proposal and submit it to NASA by jumping through the various hoops found here. NASA expects to award contracts for the studies of the Altair spacecraft in the first quarter of 2008. A total of $1.5 million is available for awards. The maximum individual award amount is $350,000. The contract performance period is six months.

In NASA-speak, proposals are due “30 days from the issue date of Jan. 11.” By my calculations, that is February 10, which is a Sunday, an odd day to have a proposal due since most of NASA’s offices are closed. Maybe its a subtle hint to get your proposals in early.

The Altair spacecraft will bring four astronauts to the lunar surface, and missions are currently scheduled to begin late in the next decade. NASA plans call for establishing an outpost on the moon through their lunar missions beginning no later than 2020.

The Constellation Program, based at NASA’s Johnson Space Center, Houston, manages the Altair Project for NASA’s Exploration Systems Mission Directorate. Constellation is developing a new space transportation system that is designed to travel beyond low Earth orbit. The Constellation fleet includes the Orion crew exploration vehicle, the Ares I and Ares V launch vehicles and Altair human lunar lander.

Find more information about the Constellation Program here.

Original News Source: NASA Constellation Program Press Release

January 15, 2008December 26, 2015 by Fraser Cain

Using Gravity to Find Planets in the Habitable Zone

Astronomers have several techniques to discover planets. But one of the least used so far, gravitational microlensing, might be just the right technique to find planets in the habitable zone of nearby dwarf stars.

The first way astronomers find planets is with the radial velocity technique. This is where the gravity of a heavy planet yanks its parent star around so that the wobbling motion too and fro can be measured.

The second technique is through transits. This is where a planet dims the light coming from its parent star as it passes in front. By subtracting the light from when the planet isn’t in front of the star, astronomers can even measure its atmosphere.

The third way is through gravitational microlensing. When two stars are perfectly lined up, the closer star acts as a natural lens, brightening the light from the more distant star. Here on Earth, we see a star brighten in a very characteristic way, and then dim down again. A blip in the change of brightness can be attributed to a planet.

Unlike the other two methods, microlensing allows you to reach out and see planets at tremendous distances – even clear across the galaxy. The problem with microlensing is that it’s a one-time opportunity. You’re never going to see those stars line up in just the same way again.

But Rosanne Di Stefano and Christopher Night from the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA think there’s another way microlensing could be used. In their research paper entitled, Discovery and Study ofNearby Habitable Planets with Mesolensing, the researchers propose that many stars have a high probability of becoming a lens.

Instead of watching the sky, hoping to see a lensing event, you watch specific stars and wait for them to pass in front of a more distant star.

These high-probablility lenses are known as mesolenses. By studying a large number of dwarf stars, they expect that many of them should pass in front of a more distant star as often as once a year. And if pick your targets carefully, like dwarf stars moving in front of the Magellanic Clouds, you might get even more opportunities.

Unlike other methods of planet detection, gravitational lensing relies on light from a more distant star. It is therefore important to ask what fraction of nearby dwarfs will pass in front of bright sources and so can be studied with lensing. Within 50 pc, there are approximately 2 dwarf stars, primarily M dwarfs, per square degree.

For less massive red dwarf stars, you should be able to see them at a distance of 30 light years, and for Sun-mass stars out to a distance of 3,000 light years. These stars are close enough that if a planet is detected in the habitable zone, followup techniques should be possible to confirm the discovery.

They calculated that there are approximately 200 dwarf stars passing in front of the Magellanic Clouds right now. And many of these will have lensing events with the stars in the dwarf galaxies.

Instead of monitoring specific stars, previous surveys have just watched tens of millions of stars per night – hoping for any kind of lensing event. Even though 3,500 microlensing candidates have been discovered so far, they tend to be with stars at extreme ranges. Even if there were planets there, they wouldn’t show up in the observations.

But if you pick your stars carefully, and then watch them for lensing events, the researchers believe you should see that brightening on a regular basis. You could even see the same star brighten several times, and make follow-up observations on its planets.

And there’s another advantage. Both the radial velocity and transit methods rely on the planet and star being perfectly lined up from our vantage point. But a microlensing event still works, even if the planetary system is seen face on.

By using this technique, the researchers think that astronomers should turn up lensing events on a regular basis. Some of these stars will have planets, and some of these planets will be in their star’s habitable zone.

Original Source: Arxiv

January 15, 2008December 26, 2015 by Ian O'Neill

Our Virtual Reality Universe

What if the Universe was in fact a simulation? A product of some information processor, creating space and time, energy and matter? What if the Big Bang was the whole simulation booting up, beginning billions of years of space and time calculations? Can we possibly understand our consciousness as a subroutine in an advanced number crunching machine? A new paper published by the Centre for Discrete Mathematics and Theoretical Computer Science, University of Auckland, asks us to keep an open mind and suggests if we look at the complexity of physical laws of our known universe, many paradoxes may be explained if we view our physical reality as a virtual reality.

Virtual reality is a term that has been used frequently in sci-fi novels and movies since the early 1980’s but the term artificial reality can be traced back to the 1970’s. Movies such as Tron, The Matrix and Lawnmower Man centre around the possibility of fully immersible virtual realities. It is only very recently however, with advanced interactive gaming systems and the design of complex virtual worlds online and on home computers, that we can experience worlds of sufficient detail that we can be fooled into believing what we are experiencing approximates physical reality. Additional systems have been engineered to provide the user with feedback from the virtual world they are interacting with (whether it is a rumble in the joypad or wired gloves giving the user a sense of touch), enhancing the experience beyond purely a visual one.

Taking a look at physics in our universe, many paradoxes and uncertainties exist. Quantum physics is one such field highlighted in Brian Whitworth’s research and considered to be “strange” physics, giving some justification to his theory we might actually be immersed in a virtual reality world:

“While virtual reality theory seems strange, so do other current theories of physics, e.g. the many-world view of quantum physics proposes that each quantum choice divides the universe into parallel universes. […] Even relatively main-stream physics theories are quite strange.” – The Physical World as a Virtual Reality.

Although this research pushes the envelope of the most outlandish physics theories, it is not so hard to imagine that advanced information processing may be complex enough to govern the dynamics of an entire universe (if the information processor was advanced enough). Our physical universe, after all, is approximated through physical equations and mathematical reasoning, why can’t the laws of our “physical” reality be approximated by virtual reality? If this can be done, do we actually exist in a virtual world?

Source: arXiv.org publication (abstract and full paper download)

January 15, 2008December 26, 2015 by Fraser Cain

Get Ready for the Great Moonbuggy Race

You can tell that NASA is really serious about sending astronauts back to the Moon – they’re even working on the moonbuggies (I mean, rovers). In order to get the best designs possible, the agency is opening up the competition to student teams to design the best lunar rovers they can. The 15th annual race is going to be in Huntsville, Alabama on April 4-5, 2008. And who knows, maybe some of their good ideas might make it all the way to the Moon.

More than 40 student teams from the US and other countries have already registered for the 15th annual Great Moonbuggy Race. The students have to design, build and then race their own two-person lunar vehicles across a simulated surface of the Moon.

Here are the important rules:

each buggy must be the work of students from a high school or institute of higher learning
it must be human powered
the unassembled vehicle must fit within a 1.2-metre (4-foot) cube
the passengers must be able to carry it 6 metres (20 feet)
the assembled vehicle has to be thinner than 1.2 metres (4 feet)
it has to carry a bunch of simulated rover equipment, like a camera, antenna, and batteries

The total length of the course is about 1,100 metres (.7 miles), and strewn with rocks, craters and other lunar hazards. The team, consisting of a male and female, have to race their rover through the terrain as quickly as possible. Each team gets two runs, and the fastest times are the winners.

The three fastest-finishing buggies in both high school and college categories will win prizes from the race sponsors. There are also awards for the most unique moonbuggy design, best overall design, most improved team, best rookie team and most spirited team

There’s still time to register for the competition – registration ends on February 1st. If you’re interested in the rules and requirements, check out NASA’s website for the Great Moonbuggy Race.

Original Source: NASA News Release