Fraser Cain, Author at Universe Today

February 5, 2008December 26, 2015 by Fraser Cain

Hubble Sees an Ancient Elliptical Galaxy

As galaxies come together through successive mergers they take on the splendid spiral shape like our own Milky Way. Keep merging those larger galaxies, though, and you’ll eventually get an elliptical galaxy – a gigantic diffuse cloud of ancient stars with little structure. Such a galaxy, NGC 1132, was recently photographed by the Hubble Space Telescope.

The elliptical galaxy NGC 1132 belongs in this class of galaxies called “giant ellipticals”. And the galaxy, with its constellation of dwarf galaxies is known as a “fossil group”. They’re the remnants and wreckage from past collisions between large galaxies.

In visible light, NGC 1132 looks like a single, isolated galaxy. But using a technique called gravitational lensing to map out the surrounding dark matter, astronomers found that it resides in a huge cloud of the stuff. In fact, NGC 1132 has as much dark matter as you might find in a group of tens or even hundreds of galaxies.

And once again, in visible light, its stars extend 120,000 light years from its centre. But in the X-ray spectrum, the glow extends 10 times as far – again, similar to a group of galaxies.

So where do fossil groups like this come from? Astronomers think they’re the end product of cosmic collisions, where a single large galaxy consumes all of its neighbors. It’s also possible they’re the result of a strange process, where something stopped moderate galaxies from forming, and only a single large galaxy came together in that region of space.

By analyzing galaxies like this, astronomers will get a better sense of galaxy evolution. It’ll help predict what’s going to happen when the Milky Way and Andromeda collide billions of years in the future.

Original Source: ESA/Hubble News Release

February 4, 2008December 26, 2015 by Fraser Cain

Venus Express Detects Water Vapour in Low Altitude Clouds

There’s a real advantage to having a spacecraft orbit a planet for days, months and even years. You have lots and lots of time to really pull in the science. And now, almost 2 years into its visit at our evil twin planet, ESA’s Venus Express has been able to map the planet’s atmosphere at lower altitudes, searching for chemicals that will help scientists understand the planet’s global climate and weather systems.

The planet’s clouds block the visible light from escaping the surface, but other wavelengths, such as infrared, do escape. Since temperatures can reach 200 degrees C at an altitude of 35 km, and more than 450 C at the surface, infrared – or heat – pours out, going right through the clouds. This radiation can then be analyzed to see the chemicals present.

ESA’s Venus Express spacecraft is equipped with a special instrument called the VIRTIS spectrometer, which can measure the atmosphere at various altitudes. It’s already mapped the high altitude clouds, and now VIRTIS has spent the last few orbits mapping the lower atmosphere.

Of course, like the rest of Venus’ atmosphere, the lower altitude clouds are dominated by carbon dioxide – the greenhouse gas that traps the heat in, raising temperatures. VIRTIS also detected carbon monoxide, a chemical that scientists weren’t expecting to see at such low altitudes.

Since carbon monoxide is so rare, scientists can use this as a way to trace global winds that cycle across the planet – sort of like dropping ink into water to study turbulence. VIRTIS was able to determine the large-scale circulation of winds as they rise at the equator and then move north and south towards the poles. Once at the poles, the winds lose altitude again, and circulate back to the beginning.

Venus Express has also detected and mapped the amount of water vapour in the lower atmosphere with high resolution. Since this molecule is so difficult to detect, this has ended a scientific debate about how much there is on Venus.

Original Source: ESA News Release

February 4, 2008April 29, 2021 by Fraser Cain

Observatory Installed on the Coldest, Driest Place on Earth

If you can’t afford to send a telescope to space, you’ll want the next best thing; a location on Earth which is cold, dry and at a high altitude. Perhaps the best place on Earth is “Dome A”, a high altitude region in Antarctica – the coldest and driest place on Earth. A team of astronomers recently climbed the summit of Dome A, and installed a new robotic observatory that should see some amazingly clear skies.

The team of scientists that made the journey represents 6 international institutions, including Texas A&M University and the Polar Research Institute of China. They arrived at Dome A on January 11th, in the middle of the southern Summer, and completed the facility installation on Saturday.

The installation is called the PLATeau Observatory, or PLATO, and was built by the University of New South Wales in Australia. PLATO is equipped with a suite of instruments that will let it measure the quality of the conditions, to confirm that it really has the best seeing on Earth. But if the calculations are correct, a 2 metre telescope here would be the equivalent of an 8-metre telescope built somewhere else. And an 8-metre telescope would rival the 30-metre supertelescopes in the works at various locations around the world.

One of the most important instruments is a set of four telescopes built at Purple Mountain Observatory in Nanjing. These are 4 telescopes with 14.5-centimetre apertures. Each one is equipped with a different filter to view the night sky at a different color or wavelength.

The facility is powered by six diesel engines that use aviation fuel in the Winter, and then it switches over to solar energy in the Summer. It will be completely autonomous, operated remotely over the low-bandwidth Iridium satellite service. Workers will then pick up the bulk of its research at the annual servicing visits.

Even in the dead of Winter, where temperatures plunge to -82 degrees Celsius, the facility will be working away gathering images. That’s because the weather around Dome A is very calm and stable. You don’t get the ferocious storms here that you see in other parts of Antarctica. It’s just cold and calm.

With PLATO installed, the team turned around and left the region on a convey of snow tractors. They’ll travel non-stop for 18 days to the coast of Antarctica, and then back to civilization.

Original Source: Texas A&M University News Release

February 4, 2008December 26, 2015 by Fraser Cain

Atlantis Will Fly, Despite Bent Hose

On Wednesday I reported that NASA was looking into a bent coolant hose on the space shuttle Atlantis. They weren’t sure if this might cause a potential launch delay while it was repaired. Shuttle managers met over the weekend, and decided that it wasn’t enough of a problem to delay the launch.

The problem is with one of the shuttle’s four braided hoses that carry the coolant needed to dissipate heat generated while in space. During a routine inspection, workers noticed that this hose had a bit of a kink in it.

The worry is that the hose could be bent further, or even snapped when the shuttle’s payload bays are closed up Sunday night to prepare for next week’s launch. In order to prevent a problem, a worker will use a long pole with a hook to guide the hose into its retraction box with the bays are closed up. Assuming that goes as planned, the shuttle’s launch won’t be delayed.

And even if the hose does break while the shuttle’s in orbit, it’s not a huge problem, according to NASA. There are a total of 4 of these hoses on Atlantis, and it can get by with the remaining ones.

With that worry out of the way, Atlantis is still scheduled for its Thursday launch from Florida’s Cape Canaveral. The shuttle is carrying Europe’s main contribution to the International Space Station: the Columbus science lab. During their time in space, the astronauts will perform three spacewalks to install the laboratory and perform some experiments.

The astronaut crew arrived in Florida today, and the countdown is expected to begin later Monday afternoon. The weather might be a problem, however. Meteorologists are predicting that there’s only a 40% chance of suitable weather on launch day. Friday should be better, though. Even if rain and clouds hold back the launch, there’s an 80% chance the shuttle will be able to lift off at the end of the week.

NASA has already canceled two launch attempts back in December because of problems with the shuttle’s fuel tank sensors. With an already crowded launch schedule, this additional delay pushes back the rest of the shuttle launches.

Original Source: NASA Status Report

February 4, 2008December 26, 2015 by Fraser Cain

Podcast: Antimatter

Sometimes, we donâ€™t get to decide what our showâ€™s about. So many threads come together at the same time driving the decision for us. This is one of those situations. Weâ€™ve gotten so many questions from listeners in just the last week about antimatter that our show had just been chosen for it. You command, we obey. Letâ€™s talk about antimatter.

Click here to download the episode

Antimatter – Show notes and transcript

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

February 4, 2008December 26, 2015 by Fraser Cain

Building a Map of Dark Energy

Understanding dark energy is probably one of the largest mysteries in cosmology right now. Figure this out, and a Nobel Prize in physics is assured. But it won’t give up its secrets so easily. Since they can’t measure dark energy directly, astronomers can only measure its effects on the large-scale structures of the Universe, and then tease out some of its characteristics.

In a recent survey using the European Southern Observatory’s Very Large Telescope, and international team of 51 astronomers from 24 institutions gathered the light from more than 13,000 galaxies. This survey contains galaxies within a 25 million cubic-light years volume.

Using this survey, they were able to map out the large scale structures in the nearby Universe, including clusters of galaxies and filamentary superclusters. By measuring the velocity of the different clusters as they speed away from us, at different times in the past, the astronomers were able to measure the speed distortion contributed by dark energy.

Their conclusions lend evidence to the so-called cosmological constant theory originally introduced by Albert Einstein – there’s some constant repulsive force that exists throughout space. But the uncertainties in their calculations doesn’t rule out other possibilities.

One of the most popular of these is known as modified gravity. In this situation, gravity just acts differently at large scales than it does in the small scale.

But the researchers feel that a measurement that might cover 10 times the volume of this survey could be able to tell the difference between a dark energy force of exotic origin or an actual modification of theory of gravity.

Original Source: ESO News Release

February 4, 2008January 24, 2021 by Fraser Cain

Astrosphere for February 4, 2008

Your image for the day is NGC 1514, captured by Stargazer 7000.

Space Politics has a look at NASA’s upcoming budget. There’s going to be a NASA briefing later today, so we’ll have more details soon.

Life everywhere? Centauri Dreams has an article about new research theorizing that terrestrial planets are common.

davep caught these cool pictures of star trails.

Astroprof talks about Mercury’s strange terrain.

Bad Astronomy reviews the presidential candidates’ views on science.

Caltech astronomer Mike Brown assures us he’s no fan of pseudo science.

February 1, 2008December 26, 2015 by Fraser Cain

Astronaut Treadmills are on the Wall

If you’re hoping to be an astronaut, I hope you like exercise. When they aren’t sleeping or doing a range of scientific activities, astronauts are exercising – upwards of 2 hours a day. This is to prevent bone mass and muscle atrophy caused by microgravity. This isn’t a perfect solution, so NASA researchers have developed a vertical treadmill that will let them imitate the conditions of space here on Earth. Now even the astronauts on the ground will have to run, run, run.

The new device, developed at NASA’s Glenn Research Center in Cleveland is called the Standalone Zero Gravity Locomotion Simulator. Instead of a regular treadmill, this is mounted to the wall. The runners are then suspended horizontally and pulled towards the treadmill to let them actually run without pushing away from the treadmill.

With this setup, astronauts are essentially getting the same workout they get in space; they no longer have to support the weight of the body over top of them. The equipment can simulate microgravity, or conditions on the Moon, where an astronaut will experience 1/6th the force of gravity. Scientists can then study the long term effects on the human body, and see what techniques will prevent bone loss and muscle atrophy.

“These studies are a key component of our research into how we can better protect astronauts,” said Linda Loerch, project manager for the Exercise Countermeasures Project at Johnson. “The focus of our work is to understand how to maintain astronaut health and performance at the highest possible levels, both on our current flights aboard the International Space Station and for future exploration beyond Earth orbit.”

There’s another advantage too. The treadmill will help give training astronauts a sense of what walking in space will be like. Combine this training with the underwater simulations, and astronauts will be much better prepared for when they step outside the space station for the first time.

Original Source: NASA News Release

February 1, 2008April 26, 2016 by Fraser Cain

Microbes Make the Best Climate Engineers

With the rising threat of global warming, you’d think humans are the best (or worst) climate engineers to arrive on planet Earth. But you’d be wrong. Tiny microbes have been modifying our climate for billions of years, and unless we learn how to work with them, we could be fighting a losing battle to get our greenhouse emissions under control.

For example, humans release tremendous amounts of methane into the atmosphere. But we do this indirectly through our livestock, rice fields and landfill. In each of these situations, it’s actually microbes producing the methane that makes such a potent greenhouse gas. We just give the microbes the environment they need to make the stuff.

In fact, unless we deeply understand how these microbes do their work, we might be fighting a losing battle to control climate change. This is based on a commentary published in the February 2008 issue of Microbiology Today. The article was written by Dr Dave Reay from the University of Edinburgh.

Much of the carbon cycle in the world involves the oceans, which breath carbon dioxide in and out of the atmosphere. But once again, it’s microbes which are taking in carbon from the atmosphere and releasing it again.

The trick, of course, is to learn how to work with them. If scientists can better understand the processes that go on, they could encourage microbes to pull more carbon out of the atmosphere, or break up methane generated in landfills. Plankton are already being used as feedstock for some biofuels, and cyanobacteria could provide hydrogen fuel.

For example, the wetlands of the Earth dump 100 million tonnes of methane into the atmosphere every year. This number would be much higher, but a significant amount is used by methanotropic bacteria before it can escape into the atmosphere. Compare this to the 150 million tonnes delivered directly to the atmosphere by human methods, like rice cultivation.

As we warm the planet, we don’t know what impact microbes might play to slow, or maybe even accelerate our actions.

“The impact of these microbially-controlled cycles on future climate warming is potentially huge,” says Dr Reay. “Microbes will continue as climate engineers long after humans have burned that final barrel of oil. Whether they help us to avoid dangerous climate change in the 21st century or push us even faster towards it depends on just how well we understand them.”

Original Source: Microbiology Today

January 31, 2008December 26, 2015 by Fraser Cain

Global Map of Iapetus

Here’s a cool global map of Saturn’s moon Iapetus, stitched together from the various Cassini flybys. Cassini didn’t see the entire moon, so the imaging team put in photographs from Voyager to cover the missing polar regions.

You can see its distinct equatorial ridge on the left-hand side of the image, and the mottled dark and light patches that give the moon its Yin-Yang look. The image scale is 803 km per pixel.

It’s a little old, but check out this video of the most recent Cassini Iapetus flyby back in September 2007.

Original Source: NASA/JPL/SSI News Release