World Needs to Aim for Near-Zero Carbon Emissions

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If we really want to combat climate change, how much carbon can we reasonably generate? How much will still push temperatures up? The current presidential candidates are all calling for serious carbon reductions over the next 40 years, but according to researchers at the Carnegie Institution for Science, it’s not enough. To really stabilize our planet’s climate, we need to get away from carbon forever.

In a recent article, published in latest issue of Geophysical Research Letters, climate scientists used a detailed Earth system model to simulate what might happen to the Earth’s climate at various levels of carbon emissions.

What’s the most carbon you can generate and not warm the planet?

“Most scientific and policy discussions about avoiding climate change have centered on what emissions would be needed to stabilize greenhouse gases in the atmosphere,” said Ken Caldeira. “But stabilizing greenhouse gases does not equate to a stable climate. We studied what emissions would be needed to stabilize climate in the foreseeable future.”

They ran various scenarios through the climate model, each time reducing the amount of carbon emissions. Even at the lowest levels, there was an increment of warming. In other words, until humans generate next to zero carbon emissions, there will be increased warming. There’s no amount that the planet can absorb on a regular basis.

Once the carbon emissions in the simulation hit zero, the levels of carbon dioxide in the atmosphere finally started to drop, getting absorbed into various carbon sinks such as the oceans and land vegetation. Even so, global temperatures remained high for at least 500 years after the end of carbon emissions.

The big worry are the climate tipping points. These are temperatures that might cause runaway processes that can’t be stopped, such as the melting of the Arctic sea ice. If the world hits some point of severe climate instability, people might need to cut their carbon emissions to the absolute minimum.

And according to this research, that’s essentially zero.

Although eliminating carbon dioxide emissions seems like a radical idea, the researchers see it as a reasonable goal.

“It is just not that hard to solve the technological challenges. We can develop and deploy wind turbines, electric cars, and so on, and live well without damaging the environment. The future can be better than the present, but we have to take steps to start kicking the CO2 habit now, so we won’t need to go cold turkey later.”

Original Source: CIS News Release

Listening to the Universe from the Far Side of the Moon

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Perhaps one of the best reasons to return to the Moon will be the boon to astronomy. Without an atmosphere, an observatory the Moon won’t have to peer through an obscuring atmosphere, but people will still be able to walk over and fix it – and even upgrade it – into the future. It’s the best of both worlds. It’s no surprise then, that engineers are working on plans for lunar observatories. When the next wave of astronauts return to the Moon, they’ll be bringing their ‘scopes.

NASA recently selected a series of 19 proposals for lunar observatories, including one suggested by a team from MIT. This observatory would help astronomers study the “Dark Ages” of the Universe, when the first stars and galaxies, and even dark matter formed.

During the first billion years after the Big Bang, there were no stars and galaxies, only opaque hot gas. When the first stars could finally form, their radiation helped ionize this gas and make it transparent. You could finally see in the Universe. It was also in this time that the mysterious dark matter formed from the soup of elementary particles, serving as a gravitational structure for matter to clump around.

The MIT proposal is called the Lunar Array for Radio Cosmology, and it’s headed by Jacqueline Hewitt, a professor of physics and director of MIT’s Kavli Institute for Astrophysics and Space Science.

It would consist of hundreds of telescope modules spread over a 2 square km area designed to pick up very-low-frequency radio emissions. Automated vehicles would crawl across the lunar surface deploying the telescopes.

The time of the Dark Ages is impossible to view from Earth because of interference from our high atmosphere as well as the background radio emissions coming from all directions. But the far side of the Moon is shielded from the Earth’s radio barrage. There it would have a clear, quiet view of the most distant Universe.

There’s another advantage with building a long-wavelength radio telescope on the complicated surface of the Moon; it’s much easier than building a fragile mirror for an optical telescope. The low wavelength radio waves don’t require a high degree of accuracy, so it will be a good test for working on surface of the Moon. Even if some of the individual modules aren’t working, or clogged with lunar dust, the full observatory will still be able to collect data.

The telescope would also be used to study coronal mass ejections coming from the Sun, and accurately measure the space weather passing through the Earth-Moon system. This is what the astronauts will use to check their local weather.

MIT will be working on a one-year study to develop a further plan for the array. If it’s actually chosen for development down the road, construction would begin after 2025 at a cost of more than $1 billion.

Original Source: MIT News Release

Podcast: Lagrange Points

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Gravity is always pulling you down, but there are places in the solar system where gravity balances out. These are called Lagrange points and space agencies use them as stable places to put spacecraft. Nature is on to them and has already been using them for billions of years.

Click here to download the episode

Lagrange Points – Show notes and transcript

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

Carnival of Space #41

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Witness the awesome power of our biggest Carnival of Space. Weighing in at a massive 22 entries, it’s docked at the New Frontiers blog. Check it out, and gasp in awe at the galaxy eating monster, a feasible magnetic catapult, the fantastic colour palette of the Hubble Space Telescope, and 19 other stories.

Click here to read the Carnival of Space #41

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.

Another Solar System Found with Saturn and Jupiter-Sized Planets

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As the search for extrasolar planets continues, researchers are finding systems more and more like our own Solar System. And today researchers announced another significant find: a system with two planets smaller than Jupiter and Saturn. It’s almost starting to sound like home.

The report, due to be published in the February 15th edition of the journal Science discusses a series of observations made back on March 28, 2006. An experiment, known as the Optical Gravitational Microlensing Equipment (OGLE), detected the telltale signal of a microlensing event on a star 5,000 light-years away.

In case you weren’t up in the latest techniques for planetary discovery, a lensing event happens when two stars line up perfectly in the sky from our perspective on Earth. The closer star acts as a natural lens, magnifying the light from the more distant star.

The curve of light coming from the event is very specific, and astronomers know when they’re seeing a microlensing event, compared to something else like a nova or a variable star.

But there are special situations, where the light from the star brightens normally, but then has an additional distortion. The gravity from planets orbiting the closer star can actually create this additional distortion. And from this, astronomers can calculate their size (amazing!). Only 4 planets had been discovered this way so far.

Okay, enough back story.

The OGLE group announced their potential lensing event, and astronomers around the world sprung into action, gathering data for the entire time that the stars were lined up.

Researchers first calculated that there was a Saturn-sized planet orbiting the star, and then another group found that there had to be a Jupiter-sized planet as well.

“Even though we observed the micolensing effect of the Saturn for less than 0.3 percent of its orbit, the observations simply could not be explained without accounting for the orbit,�? said David Bennett, a research associate professor of astrophysics from the University of Notre Dame.

Unfortunately, viewing this planetary system was a one-time event. We’ll probably never see this star line up again, so there’s no way to perform any followup observations.

Original Source: University of Notre Dame News Release

Researchers Find a Supernova, Before it Exploded

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The problem with supernovae is that you never know where they’re going to happen. Your only clue is the bright flash in the sky, and then it’s too late. But a team of European researchers think they were lucky enough to have spotted the precursor to supernova.

In an article in the February 14th issue of the journal Nature, a team of European researchers describe how they were trying to find evidence of a binary system after one of the objects detonated as a supernova. In looking back through archived images captured by NASA’s Chandra X-Ray Observatory, they were lucky enough to find one image that actually contained the system.

The supernova, known as SN 2007on exploded as a Type Ia. This is the situation where a white dwarf is in orbit around another star. It’s possible that the white dwarf feeds off material ejected from the other star until it hits a critical amount of mass – approximately 1.4 times the mass of our Sun. Or maybe it’s actually a collision between a white dwarf and another star, or between two white dwarfs.

Whatever the condition, the result is always the same. The white dwarf detonates suddenly with a very specific amount of energy and characteristic light curve. Astronomers use these explosions to measure distance in the Universe, since they’re always exploding with the same amount of energy.

To really figure out what’s going on, astronomers need more examples of these precursors. They need to be able to study a potential Type Ia supernova before it actually explodes.

So, the researchers finally have a target they can study. In the case of SN 2007on, the data gathered by the Chandra X-Ray Telescope strengthens the “mass stealing” theory. X-rays streaming from the system show the kind of fusion you would expect from a white dwarf consuming material from a neighbour.

This isn’t a slam dunk, though. A higher-quality optical image shows the binary system to be in a slightly different position from where the supernova detonated. So maybe this system isn’t the precursor after all.

But followup observations from Chandra show that the X-ray source is gone. Whatever was at that location isn’t there any more. Perhaps it did indeed vaporize in a supernova explosion.

Original Source: Chandra News Release

Arecibo Spots a Triple Asteroid

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Since asteroids have mass, they have gravity. And if you’ve got gravity, you can have moons. Several asteroids have been discovered in the outer Solar System with smaller asteroidlets circling them. But now the Arecibo radio telescope in Puerto Rico has turned up the closest example – a triple system just a mere 11 million km (7 million miles) from Earth.

Asteroid 2001 SN263 was revealed to be a triple system by Cornell astronomer Michael C. Nolan. The asteroid itself had been discovered back in 2001 as part of an automated survey. He and his colleagues captured radio images of the space rocks on February 11. By studying the images, they realized that they actually had a system of three objects.

The main central asteroid is roughly 2 km (1.5 miles) across. The larger “moon” is about half that size, and the smallest is about 300 metres (1,000 feet) across.

Asteroid systems like this have been seen in the Asteroid Belt, between Mars and Jupiter, but never so close. This allows scientists to image it with unprecedented detail.

As researchers find more and more near-Earth asteroids, they’re starting to realize that binary systems are actually quite common. According to Nolan, one in six near-Earth asteroids is a binary. Although, this is the first near-Earth triple system seen.

Multiple asteroid systems are very useful for astronomers; they provide the mass calculation. In a multiple object system like this, you can calculate the mass of each object by knowing the various periods (the time they take to complete an orbit). Researchers can then compare the mass of the binary objects to the brightness of single asteroids to estimate their masses as well.

One of the big unanswered questions: did the three objects form together, or were they captured later on? By watching the system over time, Nolan and his team will get a better sense if they’re orbiting on the exact same plane (like our Solar System). This will be evidence they formed together billions of years ago.

Arecibo is one of the best asteroid hunting tools available to astronomers; unfortunately, budget cuts in the United States has put the future of the facility in jeopardy.

Original Source: Cornell News Release

Spies Caught Selling Shuttle Secrets to the Chinese

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You wouldn’t think espionage would have much of a place here in Universe Today, but you’d be wrong. Four people in the US were arrested recently, accused of selling selling secrets to the Chinese. And what were they selling? Details about the space shuttle and other US aerospace programs.

The space shuttle? Really? Didn’t anyone tell them the program would be shelved in just a few years. And they’re not exactly the safest way to get into and back from space.

Anyway, here’s what happened.

The US justice department charged Chinese-born Dongfan Chung with 8 counts of economic espionage, conspiracy, and making false statements to FBI investigators.

The 72-year-old engineer had been working in the aerospace industry for the last 30 years, mostly at Rockwell and Boeing. He retired back in 2002, but he’d been still working as a contractor for Boeing as recently as 2006.

Apparently he sent trade secrets to China, including information on the C-17 military transport aircraft, Delta IV rocket and the B-1 bomber; in addition to information about the space shuttle.

And he’d been a spy for a long time, receiving instructions from Chinese officials as far back as 1979. In one letter sent back to China, Chung expressed a desire to contribute to the Motherland.

If convicted, Chung is looking at 100 years in prison.

So that’s one person, what about the other 3?

They’re Tai Shen Kuo, 58; Yu Xin Kang, 33; and Gregg William Bergersen, 51. Bergersen is a US weapons system policy analyst with the defense department, and was charged with conspiracy to disclose national defense information to a foreign government. Kuo cultivated a relationship with Bergersen to get the information, and Kang was ferrying it to Chinese officials.

Kuo and Kang are looking and life in prison, and Bergersen will face at least 10 years.

Original Source: Department of Justice News Release

Star Flips its Magnetic Field

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At some point in the last year or so, the Sun-like star tau Bootis completely flipped its magnetic field. The star’s north pole became its south pole, and vice versa. It this going to happen to our own Sun? Yes! Don’t panic though; in fact, it happens every 11 years or so.

Even thought the Sun’s magnetic field flip has been well observed, astronomers have never seen this happen on another star. With the Sun, the field reversals are closely linked to varying number of sunspots on its surface. The magnetic field flip happened last time in 2007, when the Sun was at the “solar minimum”.

The Earth has been recorded to change its magnetic field too, but this event has happened very erratically in the past, and theres no way to predict when it’s going to happen again in the future.

And international team of astronomers were watching the star tau Bootis with the Canada-France-Hawaii Telescope Mauna Kea as part of a survey measuring the magnetic field of stars. On one sweep the star had one configuration, and later on, the magnetic field was reversed.

Since this event happened within just two years of observations, it’s likely that tau Bootis flips its field even more quickly than the Sun’s own 11-year cycle. Even more interesting is the recent discovery that the star is orbited by a massive planet. It’s a hot Jupiter planet, six times the size of Jupiter, but only 1/20th the distance from the Earth to the Sun.

The planet is so close, it has become tidally locked with the star, similar to the way the Moon only shows one face to the Earth. It’s possible that the tidal interactions between the star and the planet somehow speed up the surface of tau Bootis, and encourage these magnetic flips.

The astronomers are planning to keep their telescopes firmly targeted at tau Bootis, checking the magnetic field of the star regularly. If it flips again, they’ll be ready.

The research was published this week in the British journal Monthly Notices of the Royal Astronomical Society.

Original Source: Institute for Astronomy News Release

Astrosphere for February 12, 2008

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Your image for the day isn’t actually a photograph. It’s a mixed-media art piece by Moya called “proto planet”. It was made using glossy cardboard paper, various types of spray paint and stencils.

Centauri Dreams notes the ongoing discoveries coming out of the 45-year old Arecibo Observatory.

Astroprof helps clear up one of the eternal questions. How do astronomers choose colours when they prepare images of the night sky?

The imaging team leader for Cassini, Carolyn Porco, is consulting on the new Star Trek movie. Let’s hope that helps them get the science right.

Starts with a Bang teaches you how to build a home in space.

Oh, and Happy Darwin Day.