Universe Today

February 19, 2008December 26, 2015 by Fraser Cain

Hubble Finds Dozens of Gravitationally Lensed Galaxies

One of the breakthroughs in modern astronomy is the use of gravitational lenses, where a closer galaxy or star focuses the light from a more distant object. The more astronomers look, the more they find these helpful objects, allowing them to peer at objects much further away. The number of known gravitationally-lensed galaxies jumped up today, when astronomers announced another 67 new lenses.

These 67 lenses were part of the COSMOS project; a detailed survey of small region of the sky about the same as 9 times the area of the Moon. Both Earth and space-based telescopes are working together to provide a survey of the sky which is very deep. And one of the key instruments in the project is the Hubble Space Telescope.

One of the big surprises of this survey is just how many lenses turned up in such a small area of the sky. Based on this discovery rate, researchers think that there could be 500,000 similar gravitationally-lenses galaxies out there.

At least 4 of the lenses are Einstein rings. This is a situation where the foreground and background galaxy are lined up so perfectly, the distorted distant galaxy forms a ring around the closer one.

In order to find the lenses, astronomers had to sift through a collection of 2 million candidate galaxies. Then the researchers had to look through each COSMOS image by eye and identify any potentially strong gravitational lenses. Finally, they checked both the foreground and background galaxy to make sure that they’re really two separate objects separated by billions of light years, and not just a strangely shaped galaxy.

Now that the researchers have so many gravitational lenses, they can do some really interesting things. For example, they’ll be able to study the dark matter distribution around the galactic lenses. And they’ll also be able to start accumulating a census of galaxy masses to see if they match predictions.

Original Source: Hubble News Release

February 19, 2008December 26, 2015 by Fraser Cain

Cassini Uncovers Invisible Rings at Saturn

Even in the smallest telescopes, Saturn’s bright rings pop into view. But those might be just the tip of the iceberg. During a recent flyby of the planet, NASA’s Cassini spacecraft noticed empty patches where the constant rain of high-energy electrons slowed down. Perhaps there are partial rings there, invisible to the spacecraft’s cameras. And where are these rings coming from?

When NASA’s Cassini spacecraft nears Saturn, its bombarded by a flurry of high energy electrons. But researchers from the Max Planck Institute for Solar System Research noticed that during the spacecraft’s journey, there were two times when it wasn’t being hit with so many particles. In their research article, published in the latest issue of the journal Icarus, they propose that there are invisible rings, generated by two of Saturn’s smallest moons: Methone and Anthe.

The gap in the rain of electrons occurred just as Cassini was passing through the orbits of Methone and Anthe. The drop in intensity lasted while the spacecraft covered a swath as wide as 1,000 to 3,000 km (600 to 1,900 miles) across. This is too wide for the tiny moons themselves, but arcs of ejected material could explain it.

“These observations tell us that even Saturn’s smallest moons could be a source of dust in the Saturnian system,” said Elias Roussos, the paper’s lead author from the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany.

So, even the smallest moons around Saturn are feeding dust into the ring system. This released material may develop into partial ring arcs because of the gravitational “tug of war” between the planet’s larger moons, like Mimas. A situation like this has been found with Saturn’s G-ring.

Where’s all this material coming from? The researchers think that the constant rain of micrometeoroids on the surface of the tiny moons dislodges the icy material. Since they’re so small and have very little gravity, it doesn’t take much for the material to escape into space.

Strangely, these theorized rings are invisible. Meteoroids are thought to be generating the faint rings at Janus, Epimetheus and Pallene; but they’re visible to Cassini. The spacecraft can’t see these newly discovered rings with its cameras. Perhaps the two different classes of moons are releasing differently-sized grains of dust.

Original Source: NASA/JPL/SSI News Release

February 19, 2008January 24, 2021 by Fraser Cain

Astrosphere for February 19, 2008

It might not look like it, but this photograph is mind-bendingly cool. The bright streak is the path of the International Space Station, and the dimmer one is the US military satellite that’s going to crash back to Earth – both seen passing through the heart of Orion. Good job Autoclub!

Centauri Dreams talks about using the Sun’s gravity as a natural telescope lens. Problem is, you have to get out to 550 AU to make it work.

The Space Review has a great article about people preparing for space tourism. So far, 93% have passed the physical tests.

In the future, solar power will rule!

APOD has a great picture of a recent spacewalk outside Columbus.

NY Times is reporting that NASA thinks it can fix a serious flaw in its Ares rocket design.

Astropixie wants to be Stephen Colbert’s astrophysicist.

And finally, one of the best posts of read in a long time. Phil perfectly explains why science isn’t faith.

February 19, 2008December 26, 2015 by Nancy Atkinson

Space Program At Risk, Panel Says

A panel of 50 space experts met recently to discuss NASA’s current direction with its Vision for Space Exploration. While the conference, “Examining the Vision: Balancing Science and Exploration” was seemingly billed as forum for discussing alternatives to the moon/Mars vision, attendees endorsed NASA’s current direction and then concluded what anyone with an eye on NASA already knew: NASA isn’t receiving adequate funds in line with the grand goal of sending humans to Mars.

The panel of scientists, engineers, and former astronauts and NASA administrators concluded that NASA is on the right path with its objectives of going to the moon as a stepping stone to reach Mars, but those goals are in danger because of chronic underfunding to the US space program.

“The nation’s space program is in peril,” said Stanford Professor Scott Hubbard, former director of NASA’s Ames Research Center, and an organizer of the conference. “You simply cannot continue doing more with less and meet these goals. That is a fact. This workshop achieved a consensus that NASA’s resources have not been commensurate with its mandated missions of exploration and science.”

The panel did say, however, that NASA should focus more on sending humans to Mars instead of building large bases on the moon. But also, former astronaut Kathryn Thornton said before the meeting, she felt the best way to get to Mars was going there directly. But the meeting changed her mind, she said, and she now believes there are benefits to using the moon as a way station, such as scientific research and testing rocket hardware and infrastructure.

Alternatives such as going to asteroids was discussed, but not endorsed by the panel. Also of interest is that the panel said science is not the major motivation for human spaceflight.

But the panel concluded that any human ventures out of low earth orbit should be international in nature. “The next administration should make the human spaceflight goal an international venture focused on Mars–both to bring in more public support and to sustain the program politically,” said Louis Friedman, Executive Director of The Planetary Society.

In particular the attendees agreed to the following statements:

It is time to go beyond LEO with people as explorers. The purpose of sustained human exploration is to go to Mars and beyond. The significance of the Moon and other intermediate destinations is to serve as steppingstones on the path to that goal.
Bringing together scientists, astronauts, engineers, policy analysts, and industry executives in a single conversation created an environment where insights across traditional boundaries occurred.
Human space exploration is undertaken to serve national and international interests. It provides important opportunities to advance science, but science is not the primary motivation.
Sustained human exploration requires enhanced international collaboration and offers the United States an opportunity for global leadership.
NASA has not received the budget increases to support the mandated human exploration program as well as other vital parts of the NASA portfolio, including space science, aeronautics, technology requirements, and especially Earth observations, given the urgency of global climate change.

The panel gathered privately on Feb. 12-13, 2008 to discuss space policy options facing the new US administration that will take office in January 2009, and may offer more recommendations in the future.

Original News Sources: New Scientist, Planetary Society Press Release

February 18, 2008December 26, 2015 by Fraser Cain

World Needs to Aim for Near-Zero Carbon Emissions

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

February 18, 2008December 26, 2015 by Fraser Cain

Listening to the Universe from the Far Side of the Moon

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

February 18, 2008December 26, 2015 by Fraser Cain

Podcast: Lagrange Points

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.

February 18, 2008December 26, 2015 by Nancy Atkinson

Rocky Planets May Form Around Most Sun-like Stars

Astronomers have found numerous Jupiter-like planets orbiting other stars. But because of the limits of our current technology, they haven’t yet found any other terrestrial Earth-like planets out in the universe. But new findings from the Spitzer Space Telescope suggest that terrestrial planets might form around many, if not most, of the nearby sun-like stars in our galaxy. So perhaps, other worlds with the potential for life might be more common than we thought.

A group of astronomers led by Michael Meyer of the University of Tucson, Arizona used Spitzer to survey six sets of stars with masses comparable to our sun, and grouped them by age.

“We wanted to study the evolution of the gas and dust around stars similar to the sun and compare the results with what we think the solar system looked like at earlier stages during its evolution,” Meyer said. Our sun is about 4.6 billion years old.

They found that at least 20 percent, and possibly as many as 60 percent, of stars similar to the sun are candidates for forming rocky planets.

The Spitzer telescope does not detect planets directly. Instead, using its infrared capability, it detects dust — the rubble left over from collisions as planets form — at a range of infrared wavelengths. Because dust closer to the star is hotter than dust farther from the star, the “warm” dust indicates material orbiting the star at distances comparable to the distance between Earth and Jupiter.

Meyer said that about 10 to 20 percent of the stars in the four youngest age groups shows ‘warm’ dust, but not in stars older than 300 million years. That is comparable to the theoretical models of our own solar system, which suggests that Earth formed over a span of 10 to 50 million years from collisions between smaller bodies.

But the numbers are vague on how many stars are actually forming planets because there’s more than one way to interpret the Spitzer data. “An optimistic scenario would suggest that the biggest, most massive disks would undergo the runaway collision process first and assemble their planets quickly. That’s what we could be seeing in the youngest stars. Their disks live hard and die young, shining brightly early on, then fading,” Meyer said.

“However, smaller, less massive disks will light up later. Planet formation in this case is delayed because there are fewer particles to collide with each other.”

If this is correct and the most massive disks form their planets first and then the smaller disks take 10 to 100 times longer, then up to 62 percent of the surveyed stars have formed, or may be forming, planets. “The correct answer probably lies somewhere between the pessimistic case of less than 20 percent and optimistic case of more than 60 percent,” Meyer said.

In October 2007, another group of astronomers used similar Spitzer data to observe the formation of a star system 424 light-years away, with another possible Earth-like planet being created.

More definitive data on formation of rocky planets will come with the launch the Kepler mission in 2009, which will search to find if terrestrial planets like Earth could be common around stars like the sun.

Original News Source: JPL Press Release

February 18, 2008December 26, 2015 by Nancy Atkinson

Shuttle Crew Says Goodbye, Undocks from ISS

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After a successful visit to the International Space Station, the crew of space shuttle Atlantis said farewell and undocked from the station at 4:24 am EST Monday morning. Their busy nine-day stay included three spacewalks and the installation of the European Columbus science module, as well as a switch-out in crew. European astronaut Leopold Eyharts stays on the ISS while US astronaut Dan Tani returns home after a four-month expedition on the station.

“We just wanted to thank you again for being a great host and letting us enjoy your station for about a week,” shuttle commander Steve Frick radioed to the ISS before undocking. “We had a great time over there, we learned a lot and we really, really enjoyed working with your crew, one quarter of which we have here and we’re happy to take Dan home. But just again, to you and to Yuri and to Leo, thanks very much.”

“Well thank you guys,” station commander Peggy Whitson replied. “Itâ€™s a great new room you’ve added on and we really appreciate it. Get Dan home safe, and thanks!”

In an emotional farewell ceremony on Sunday, Tani reflected on his extended mission. The delay of Atlantis’ mission due to fuel sensor problems made his stay in space almost two months longer than originally planned. During his time on the station, Tani’s mother, who he called his “inspiration” was killed in a car accident. He said he can’t wait to get back home to be with his family.

But his recent experiences have given him great hope for the future.

“Today I feel very optimistic about our space program and our society because I’m here, I’ve spent time with a man from France, from Italy and from Germany and from Russia,” he said. “Nations that have not always been friendly are now cooperating and we’re doing great things.”

With shuttle pilot Alan Poindexter at the controls, the shuttle did a one-loop fly around of the station before departing. Atlantis’ crew is inspecting the shuttle’s heat shield to get the final OK for landing, which is scheduled for shortly after 9:00 am Wednesday morning, if the weather holds in Florida. Both the Kennedy Space Center and the backup landing site in California will be ready as NASA wants the shuttle to land that day to give the military enough time to destroy a damaged spy satellite.

The next shuttle flight is coming right up. Endeavour began its crawl to the launch pad early Monday in to prepare for a March 11 liftoff.

North American residents with clear skies Monday evening should be able to see both Atlantis and the ISS flying in tandem. See NASAâ€™s orbital tracking site or Heavenâ€™s Above for sighting times for your area.

February 17, 2008December 26, 2015 by Tammy Plotner

Countdown To February 20/21 Total Lunar Eclipse…

From beginning to end, the February 20/21 lunar eclipse lasts about three hours and twenty-six minutes and we’re down to less than 72 hours to prepare. While that seems like plenty of time, photographers will want to note that Saturn will be joining the eclipse show as well!

Although the separation will vary slightly with the observer’s position on Earth, for most of us the bright, yellowish visage of Saturn will be less than 3 degrees away from the Moon’s northern limb. For those of you who enjoy photographing the night sky, this will be a tremendous opportunity to both capture an astronomy event and a conjunction at the same time! This type of event – when things interestingly align in the sky is also sometimes called an “appulse”. For all we know, we could even be experiencing a syzygy!

Regardless of what word you want to put on it, it’s definitely going to be a sight worth seeing. Let’s take a look at where the action is happening!

For viewer on Eastern Standard Time the eclipse will enter the partial phase on February 20 at 08:43 pm; for Central Standard Time, 07:43 pm; for Mountain Standard Time, 06:43 pm; and Pacific Standard Time at 05:43 pm – before sunset. For viewers in Europe and Africa, the action begins at the beginning of a new day – on February 21 at 01:43 am GMT. (Sorry, to the good folks down under and in the Far East… no eclipse will be visible.) Totality will begin at 10:01 pm EAST, 09:01 pm CST, 08:01 pm, MST, 07:01 pm PST, and 03:01 am GMT and end precisely 50 minutes later. Then, you have 1 hour and 18 minutes left as the Moon slowly slides out of the Earth’s shadow once again.

For a significant portion of “Universe Today” readers, the entire eclipse will be visible and it’s time to enjoy the last we’ll see for a couple of years. For those experiencing the eclipse as the Moon sets… Don’t despair. You’ll enjoy one of the darkest eclipses you’ll ever see while viewers on the west coast of the Americas will see the eclipse in progress as the Moon rises. Don’t wait until the last minute to prepare your observing area or your cameras. For those with camcorders, you have a great opportunity to video the entire event! Don’t forget that cell phones take great images and even the most common camera can take a great shot of the eclipsed Moon when held to the eyepiece of a telescope. If you’re timing the event, have your notes ready, and most of all… Have a good time!

Wishing all of you clear skies!