Universe Today

February 19, 2009December 24, 2015 by Nancy Atkinson

Kaguya Captures Eclipse — From the Moon

Penumbral Lunar Eclipse as seen from the Moon. Credit: JAXA

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Here’s something you don’t see everyday. In fact, this is the first time this has ever been seen. On Feb. 10 Japan’s Kaguya spacecraft in orbit around the moon successfully took an image of a penumbral lunar eclipse. That’s the Earth passing in front of the sun, as seen from the Moon. From the Moon! The image was taken just at the moment when the Earth covered up most of the sun, creating a diamond ring effect. If we’re lucky on Earth, we can see this effect in a solar eclipse, when the Moon blocks the Sun as seen from Earth. Here, Earth’s atmosphere is lit up by the sun, creating the ring and just enough sunlight is sneaking by on one side of the Earth, creating the diamond. Sensational! Plus, there’s a movie of the eclipse, too!

A penumbral lunar eclipse is a phenomenon in which the Sun, Earth and Moon line up in tandem, and the moon is in the Earth’s penumbra, or, when you look from the Moon, the Sun is partially covered by the Earth (partial eclipse.) When the phenomenon occurs, the volume of light from the Sun to the Moon decreases, making the Moon’s surface look darker when you see it from the Earth.

The Bad Astronomer waxes eloquently about the event, so give him a visit.

Source: JAXA

February 19, 2009December 24, 2015 by Anne Minard

NASA’s Kepler Mission Ready for Launch

Technicians working inside the Astrotech Space Operations facility near NASA's Kennedy Space Center look over the Kepler spacecraft soon after it arrived in Florida in preparation for launch. Image credit: NASA/Tim Jacobs

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NASA’s Kepler spacecraft is ready to be moved to the launch pad today and will blast off within weeks, with a mission to address an age-old question: Are we alone?

Kepler is scheduled to blast into space from Florida’s Cape Canaveral Air Force Station aboard a Delta II rocket on March 5 at 10:48 p.m. eastern time (7:48 p.m. Pacific). It is the first mission with the ability to find planets like Earth — rocky planets that orbit sun-like stars in a warm zone where liquid water could be maintained on the surface. If Earth-sized and slightly larger planets are as common around other stars as some astronomers suspect, Kepler could spy hundreds of them within the next few years.

If so, “life may well be common throughout our universe,” said William Borucki, NASA’s principal investigator for Kepler science, who spoke about the mission Thursday afternoon at a NASA press conference. “If on the other hand we don’t find any, that will be another profound discovery. In fact it will mean there will be no Star Trek.”

The Kepler mission will spend three and a half years surveying more than 100,000 sun-like stars in the Cygnus-Lyra region of our Milky Way galaxy. Its telescope is specially designed to detect the periodic dimming of stars that planets cause as they pass by. Some star systems are oriented in such a way that their planets cross in front of their stars, as seen from our Earthly point of view. As the planets pass by, they cause their stars’ light to slightly dim, or wink.

The telescope can detect even the faintest of these winks, registering changes in brightness of only 20 parts per million. To achieve this resolution, Kepler will use the largest camera ever launched into space, a 95-megapixel array of charged couple devices, known as CCDs.

“If Kepler were to look down at a small town on Earth at night from space, it would be able to detect the dimming of a porch light as somebody passed in front,” James Fanson, Kepler project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a press release. During the briefing he added that the resolution is “akin to measuring a flea as it creeps across the headlight of an automobile at night. That’s the level of precision we have to achieve.”

Fanson added that Kepler, at a cost of about $500 million, is “the most complex piece of space flight hardware ever built” by the Boulder, Colorado-based Ball Aerospace & Technologies Corp.

The exoplanet research field has already proven exciting, Borucki said. Just over three hundred exoplanets have been detected so far, most of them gas giants like Jupiter and Saturn because those are the easiest to spot with pre-Kepler instruments. Already, the known exoplanets are an eclectic bunch.

“We’re finding planets that [would] float like foam on water,” Borucki said. “We’re finding planets with the density of lead.” And whereas researchers were expecting planet with orderly, circular orbits and sizes that increased with distances from stars, they’re finding a chaotic mix of behaviors — eccentric orbits, and giant, gaseous worlds so close to their parent stars that they complete full orbits within days.

By staring at one large patch of sky for the duration of its lifetime, Kepler will be able to watch planets periodically transit their stars over multiple cycles, allowing astronomers to confirm the presence of planets and use the Hubble and Spitzer space telescopes, along with ground-based telescopes, to characterize their atmospheres and orbits. Earth-size planets in habitable zones would theoretically take about a year to complete one orbit, so Kepler will monitor those stars for at least three years to confirm the planets’ presence.

The first objects likely to be reported will be the Jupiter- and Saturn-sized planets, and gradually — as confirmations roll in and detections get more focused — Neptune and then Earth-sized detections will be more likely to emerge, said exoplanet hunter Debra Fischer of San Francisco State University in California, who is not directly involved with the mission.

“We have a good chance of finding Mars-size planets, and a possibility of finding Mercury-sized planets” with Kepler, she said. “We don’t think we can do better than that.”

The scientists are in no rush to announce new discoveries until they’re “bulletproof,” they said — which could translate into years of suspense for the world’s Trekkies.

“We don’t want to have false discoveries,” Borucki said. “We want to be sure when we say it’s an earth, its an earth.”

Source: NASA teleconference and press release.

February 19, 2009December 24, 2015 by Anne Minard

Fermi Glimpses Wildest-Ever Gamma-Ray Blast

GRB 080916C’s X-ray afterglow appears orange and yellow in this view that merges images from Swift’s UltraViolet/Optical and X-ray telescopes. Credit: NASA/Swift/Stefan Immler

Researchers using the Fermi Gamma-ray Space Telescope are reporting a gamma-ray explosion that blows away anything they’ve seen before. The blast, recorded last fall in the constellation Carina, released the energy of 9,000 supernovae.

The collapse of very massive stars can produce violent explosions, accompanied by strong bursts of gamma-ray light, which are some of the brightest events in the universe. Typical gamma-ray bursts emit photons with energies between 10 kiloelectron volts and about 1 megaelectron volt. Photons with energies above megaelectron volts have been seen in some very rare occasions but the distances to their sources were not known. An international research consortium is reporting in this week’s issue of the journal Science Express that the Fermi Gamma-Ray Space Telescope has detected photons with energies between 8 kiloelectron volts and 13 gigaelectron volts arriving from the gamma-ray burst 080916C.

formerly_glast — Fermi, formerly known as GLAST, pictured pre-launch in the spring of 2008. Photo credit: NASA/Dimitri Gerondidakis

The explosion, designated GRB 080916C, occurred just after midnight GMT on September 16 (7:13 p.m. on the 15th in the eastern US). Two of Fermi’s science instruments — the Large Area Telescope and the Gamma-ray Burst Monitor — simultaneously recorded the event. Together, the two instruments provide a view of the blast’s gamma-ray emission from energies ranging from 3,000 to more than 5 billion times that of visible light.

A team led by Jochen Greiner at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, established that the blast occurred 12.2 billion light-years away using the Gamma-Ray Burst Optical/Near-Infrared Detector (GROND) on the 2.2-meter (7.2-foot) telescope at the European Southern Observatory in La Silla, Chile.

“Already, this was an exciting burst,” says Julie McEnery, a Fermi deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “But with the GROND team’s distance, it went from exciting to extraordinary.”

Astronomers believe most gamma-ray explosions occur when exotic massive stars run out of nuclear fuel. As a star’s core collapses into a black hole, jets of material — powered by processes not yet fully understood — blast outward at nearly the speed of light. The jets bore all the way through the collapsing star and continue into space, where they interact with gas previously shed by the star. This generates bright afterglows that fade with time.

The burst is not only spectacular but also enigmatic: a curious time delay separates its highest-energy emissions from its lowest. Such a time lag has been seen clearly in only one earlier burst, and researchers have several explanations for why it may exist. It is possible that the delays could be explained by the structure of this environment, with the low- and high-energy gamma rays “coming from different parts of the jet or created through a different mechanism,” said Large Area Telescope Principal Investigator Peter Michelson, a Stanford University physics professor affiliated with the Department of Energy.

Another, far more speculative theory suggests that perhaps time lags result not from anything in the environment around the black hole, but from the gamma rays’ long journey from the black hole to our telescopes. If the theorized idea of quantum gravity is correct, then at its smallest scale space is not a smooth medium but a tumultuous, boiling froth of “quantum foam.” Lower-energy (and thus lighter) gamma rays would travel faster through this foam than higher-energy (and thus heavier) gamma rays. Over the course of 12.2 billion light years, this very small effect could add up to a significant delay.

The Fermi results provide the strongest test to date of the speed of light’s consistency at these extreme energies. As Fermi observes more gamma-ray bursts, researchers can look for time lags that vary with respect to the bursts. If the quantum gravity effect is present, time lags should vary in relation to the distance. If the environment around the burst origin is the cause, the lag should stay relatively constant no matter how far away the burst occurred.

“This one burst raises all sorts of questions,” Michelson says. “In a few years, we’ll have a fairly good sample of bursts, and may have some answers.”

Source: Eurekalert

February 19, 2009December 24, 2015 by Fraser Cain

Is the Earth Round?

The Earth isn’t flat, that’s for sure. And if you look at a photograph, the Earth really looks round. But how round is it?

The actual shape of the Earth is actually an oblate spheroid – a sphere with a bulge around the equator. The Earth is bulged at its equator because it’s rapidly rotating on its axis. The centripetal force of the rotation causes the regions at the equator to bulge outward. And it actually makes a pretty big difference. The diameter of the Earth, measured across the equator is 43 km more than when you measure the diameter of the Earth from pole to pole.

This bulge has some interesting implications. For example, it means that the point on Earth furthest from the center isn’t actually Mount Everest, but Mount Chimborazo in Ecuador. Only because Chimborazo is closer to the Earth’s equator.

So how smooth is the Earth. When billiard balls are manufactured, they aim for a tolerance of 0.22%. The Earth has a tolerance of 0.17%, so it’s actually smoother than a billiard ball. If you could hold the Earth in your hands, it would feel smoother than a billiard ball.

But the Earth definitely isn’t flat.

We have written many articles about the Earth for Universe Today. Here’s a cool article about looking at the Earth as if it’s an extrasolar planet.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.

February 19, 2009December 24, 2015 by Fraser Cain

What is the Tallest Volcano on Earth?

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The tallest volcano on Earth is Mauna Kea, one of the 5 volcanos that make up the Big Island of Hawaii. The summit of Mauna Kea is 4,205 meters above sea level, but its true height is much larger. When measured from the sea floor, Mauna kea is more than 9,000 meters tall, making it the tallest mountain on Earth.

Mauna Kea is part of the network of volcanos above the Hawaiian hotspot. The tectonic plate that has the Hawaiian islands is slowly moving above the hotspot, and it recently carried Mauna Kea away from the hotspot. Scientists believe that Mauna Kea is now dormant; it last erupted about 4,500 years ago. Although, researchers do think it’s going to erupt again, the time between eruptions is measured in hundreds of years. The most active volcano on the island, Kilauea, erupts every few years.

Even though the Hawaiian islands are warm and tropical, Mauna Kea is so tall that it has regular snowfalls in the winter months. Geologists have even found deposits created by glaciers during recent ice ages. There were probably three glacial episodes in the last 200,000 years. People regularly ski on the slopes of Mauna Kea.

Although Mauna Kea is the tallest volcano, it’s only about 40 meters taller than the nearby Mauna Loa, which is the biggest volcano on Earth. Mauna Loa has more than 75,000 cubic kilometers of material.

And the biggest volcano in the Solar System isn’t on Earth, but on Mars. The enormous Olympus Mons is 27 km tall, and contains 100 times more material than Mauna Loa.

We have written many articles about the Earth for Universe Today. Here’s an article about the biggest volcano on Earth, and here’s an article about the biggest volcano in the Solar System.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.

February 19, 2009December 24, 2015 by Fraser Cain

What is the Biggest Volcano on Earth?

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The largest volcano on Earth is Mauna Loa, which is one of the 5 volcanoes that make up the Big Island of Hawaii. When we talk about biggest volcano here, we’re talking about the volcano that has the biggest volume, and that’s Mauna Loa. It’s made up of an estimated 75,000 cubic kilometers of material.

Mauna Loa is an active shield volcano, and scientists think that it has been erupting for about 700,000 years; it emerged through the surface of the ocean about 400,000 years ago. The active magma for Mauna Loa comes from the Hawaiian hotspot. But the plate carrying the massive volcano is slowly carrying it away from the hotspot, and it will go extinct in the next 500,000 to 1 million years. It last erupted in 1984, and destroyed homes and villages in 1926 and 1950.

The volcano measures 4,169 meters above sea level, but that’s not its true height. Measured from the sea floor, Mauna Loa is really taller than 9,000 meters – that’s taller than Mount Everest. But Mauna Loa isn’t the tallest volcano, that’s actually its neighbor, Mauna Kea, which is about 40 meters taller.

The biggest volcano in the Solar System isn’t on Earth, but on Mars. Olympus Mons, on Mars, measures 27 km high, and has about 100 times the volume of Mauna Loa.

We have written many articles about the Earth for Universe Today. Here’s an article about the biggest volcano in the Solar System, and here are some great images of a lightning storm around a volcano.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.

February 19, 2009December 24, 2015 by Ian O'Neill

Next ATV Will Be Named Johannes Kepler

Jules Verne arrives at the ISS. Johannes Kepler is next... (NASA)

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The next Automated Transfer Vehicle (A T V) to be launched to supply the International Space Station (ISS) has been officially named. Currently being assembled in Germany, the next ATV will honour the great 17th Century German scientist, Johannes Kepler.

The very first ATV was named after the legendary French science fiction writer, Jules Verne, and launched on an extended 5 month mission to the orbiting outpost where it delivered supplies, gave the station a helpful re-boost and then carried out an extreme garbage disposal effort, burning up over the Pacific Ocean on September 5th, 2008.

After it is launched on a similar resupply mission in 2010, the same fate awaits ATV Johannes Kepler. Or does it…

The ATV is Europe’s most advanced spacecraft ever built. Last year, Jules Verne wowed the world as it was launched into orbit, completed a flyby of the station (at a distance of 30 km) and then carried out a series of tests (including the critical Collision Avoidance Manoeuvre) before waiting in a parking orbit, 2000 km from its destination.

This was a particularly busy time for the ISS as Jules Verne had to wait for Space Shuttle Endeavour to finish its mission (STS-123) to attach the Japanese Kibo module and Canadian robotic arm. After Endeavour returned to Earth, the ATV was clear to dock on April 3rd.

So next year, it will be ATV Johannes Kepler’s turn to carry out a fully automated docking procedure with the space station to deliver food, water, propellant and oxygen. As with Jules Verne, Johannes Kepler is expected to provide a re-boost option, pushing the ISS to a slightly higher orbit.

However, Johannes Kepler might be saved from the fiery re-entry its predecessor had to endure. The European Space Agency, overjoyed at the success of Jules Verne, has asked the space industry for advice on how the ATV might be upgraded, to allow for the safe return of cargo to Earth and possible astronaut transportation. A feasibility study was approved at a meeting in The Hague in November 2008.

Interestingly, there will be another mission already in space in 2010 bearing the same name as the second ATV. The exoplanet-hunting Kepler telescope is set for launch next month.

Source: BBC

February 18, 2009December 24, 2015 by Nancy Atkinson

New HiRISE Images: Winter Turning to Spring in Mars’ Southern Hemisphere

Proctor Crater on Mars during winter. Credit: NASA/JPL/U of AZ

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If you’ve never seen the “Springtime on Mars 2020” video, its a fun (if not Wall-E-ish) view of what Mars could be like sometime in the future. But now in 2009, winter is turning to spring in Mars’ southern hemisphere, and the HiRISE camera on board the Mars Reconnaissance Orbiter is busy snapping high resolution images of planet’s surface. In the winter the dunes shown here in Proctor Crater are covered with seasonal carbon dioxide frost (dry ice). In the spring, the frost gradually evaporates but lingers in protected regions. In this color image bright ice deposits in sheltered areas highlight the ripples on the dunes. Now that MRO has been in orbit for two Martian winters, this image of Proctor Crater can be compared with the images of these dunes that were taken during the first year of MRO’s mission. Scientists are comparing the images to study inter-annual variability. See an image from January 2007 of Proctor Crater below, as well as more new images from HiRISE.

Proctor Crater dune field, 2007. Credit: NASA/JPL/U of AZ

Here’s how Proctor Crater looked two years ago (one Martian late winter ago), in January 2007. The crater is located -47.2 degrees latitude, and 33.9 degrees longitude East.

South pole CO2. Credit: NASA/JPL/U of AZ

Every southern winter the south polar region of Mars is covered with an approximately 1 meter deep layer of frozen carbon dioxide (dry ice). In the spring, when the sun begins to warm the surface below the translucent ice, gas flow under the ice carries loose dust from the surface up onto the top.

The dust falls to the surface in fans, whose orientation is determined by the direction of the local wind flow. Fans from one source region pointing in multiple directions show how the wind direction has changed. Narrow fans pointing in just one direction are the most recent. Alternatively, the vent from the surface may have re-annealed, such that these fans were formed over a very limited time span.

Not quite so far south, at just -28.4 degrees latitude, is Hellas Basin. The detail of this image is amazing, and even though its not a 3-D image, it almost appears so, because of the depth of the detail.

This image shows part of the floor of an impact crater on the northern rim of the giant Hellas Basin.

Hellas includes the lowest elevations on Mars, and may have once held lakes or seas; layered rock outcrops occur around much of the edge of the basin. At this site, a large impact crater (about 90 kilometers across) was partly filled by layered rocks. These rocks on the crater floor are now eroding and forming strange pits.

Here, the layers are mostly exposed on a steep slope which cuts across much of the image. On this slope, they crop out as rocky stripes, some continuous and others not. The material between the stripes is mostly covered by debris, but some areas of exposed rock are visible. The slope is capped by a thick, continuous layer that armors it against erosion; once this cap is gone, the lower material is removed rapidly, forming the steep slope. At the base of this slope, rocks on the floor of the pit appear bright and heavily fragmented by cracks known as joints.

Great images — keep ’em coming, HiRISE!

For more info see the HiRISE site.

February 18, 2009December 24, 2015 by Nancy Atkinson

Where In The Universe #43

It’s Wednesday, so that means its time for another “Where In The Universe” challenge to test your visual knowledge of the cosmos. See if you can name where in the Universe this image is from, and give yourself extra points if you can name the spacecraft responsible for the image. Make your guess and post a comment. Check back sometime on Thursday to find the answer and see how you did (and yes, I’ll try to remember to post the answer in a timely fashion this week!)

UPDATE: The answer has now been posted below.

Pretty much everyone said this was Europa, and guess what, you’re right! This highly detailed image of Jupiter’s moon Europa was taken by the Galileo spacecraft. It’s a processed image to show the differences in materials that cover the ice. The red linear features are cracks and ridges that stretch for thousands of kilometres across the moon’s surface, resulting from tides raised by the pull of Jupiter. The mottled red terrain shows areas that have been disrupted and where ice blocks have moved around. The red material is thought to be a non-ice contaminant, such as salts brought up from the ocean thought to lie beneath Europa’s icy shell. Image: NASA/JPL/University of Arizona.

Great job everyone, and check back again next week for another WITU Challenge!

February 18, 2009December 24, 2015 by Fraser Cain

What is the Biggest Island on Earth?

The largest island on Earth is Greenland, with a total land area of 2.2 million km².

This is a bit of a complicated question because it’s hard to define the difference between an island and a continent. Both Antarctica and Australia are larger than Greenland, but they’re continents, so they’re out.

As you probably know, Greenland sits up near the Earth’s north pole, in between North America and Europe. More than 80% of the island is covered by glaciers, some of which can be more than a kilometer thick. With such an extreme environment, Greenland is sparsely populated; roughly 60,000 people live on the island, and most of those live in the capital city of Nuuk, on the southern island.

If you’re interested, the second largest island on Earth is New Guinea, with 785,000 square kilometers. And the third largest island is Borneo, with 748,000 km.

We have written many articles about the Earth for Universe Today. Here’s an article about how scientists measure melting ice in Greenland, and how snow melt is on the rise in Greenland.

Want more resources on the Earth? Here’s a link to NASA’s Human Spaceflight page, and here’s NASA’s Visible Earth.

We have also recorded an episode of Astronomy Cast about Earth, as part of our tour through the Solar System – Episode 51: Earth.