Fraser Cain, Author at Universe Today

May 16, 2007December 26, 2015 by Fraser Cain

Frictional Heating Creates the Plumes on Enceladus

Just the way you can rub your hands together on a cold day to warm them up, the process of frictional heating can warm up an object in space. We see this through Jupiter’s interactions with Io, and now, astronomers report, that’s the same process that’s causing geysers of ice to erupt on Saturn’s moon Enceladus.

New research from the University of California, Santa Cruz, proposes that the gravitational interaction between Enceladus and Saturn causes the moon to flex as it orbits. Enceladus’ orbit is eccentric, varying its distance to Saturn, and it’s this eccentricity that creates the flexing. The faults on Enceladus to rub together, producing enough heat to transform solid ice into plumes of water vapour and ice crystals.

The researchers calculated how much heat could be generated by this flexing, and determined that it matches the observations made by NASA’s Cassini spacecraft during its flybys. Cassini detected tiger striped fissures around the Enceladus’ southern pole, and these geysers of water ice.

Another promising prediction is that Enceladus must have an ocean of liquid water beneath the icy shell for this flexing process to work at all. If the moon had a solid rock interior, it wouldn’t flex, and wouldn’t generate the ice geysers. This is good news for astrobiologists, since life on Earth exists wherever there are quantities of liquid water. This ice shell has to be at least 5 km (3 miles) thick, and is probably much thicker.

Original Source: UCSC News Release

May 16, 2007December 26, 2015 by Fraser Cain

Astrosphere for May 16, 2007

Follow me around the astrosphere. Here we go:

One of the most important extrasolar planetary discoveries of the year was announced yesterday – a new Neptune-sized planet. Since there wasn’t an official press release, the news has been gathering slowly. A few bloggers have already jumped on the story and have some analysis. systemic, and Centauri Dreams both have great articles. I’ll get mine done in a few hours.

Missed NASA’s Lunar Regolith challenge? Well, you can see some videos of the hardy diggers trying to win the prize. Jim, and his All Over the Map Blog has the links. Thanks to Hobbyspace for the find.

The Internet works so well because computers can talk to each other, regardless of platform, hardware, software, or operating system. That’s not the case in space, and Space Pragmatism thinks that’s going to be a problem. What happens when an astronaut on the Moon needs to send an emergency message, but the only satellite in view can’t relay the signal?

May 15, 2007December 26, 2015 by Fraser Cain

Antarctica Had Vast Regions Melt Recently

Much of the concern for global warming has been focused on the Arctic Ocean, where sea ice is disappearing faster than scientists had predicted. The southern regions of the Earth didn’t seem to be as affected. But new satellite images from NASA’s QuikScat satellite are showing that Antarctica is melting too.

QuikScat measured snowfall accumulation and melting in Antarctica, tracking the period from July 1999 through July 2005. Scientists analyzing the results found that several distinct regions across the continent were accelerating their rate of snow melt. And these regions were places nobody would have anticipated. There was evidence of melting 900 km (560 miles) inland from the open ocean, only 500 km (310 miles) from the South Pole, and 2,000 metres (6,600 feet) above sea level.

These melting regions don’t actually reach the sea; however, they refreeze into an extensive ice layer. The water can penetrate into ice sheets through cracks and glacial shafts, and then lubricate the underside of the ice sheet at the bedrock, causing the ice mass to move more quickly towards the ocean, and raising sea levels.

Original Source: NASA/JPL News Release

May 15, 2007December 26, 2015 by Fraser Cain

Atlantis Rolls out to the Launch Pad

The Space shuttle Atlantis made the slow and steady journey out to its launch pad today, in preparations for its June 8 launch to return to the International Space Station and continue construction. With Atlantis back on its launch pad, NASA feels confident that the shuttle is fully repaired from the hailstorm that chewed up its foam insulation back in March.

The shuttle left the Vehicle Assembly Building at 5:02am local time, and crawled along at 1.4 kph (1 mph) for six hours and 45 minutes. With Atlantis at the launch pad, workers spent the rest of the day connecting up the electrical and mechanical umbilicals from the launch platform. This is the first time that a shuttle has blasted off from Launch Pad 39A in four years.

Atlantis is carrying the S3/S4 truss, which will be installed onto the International Space Station in June. During their 11-day mission, the astronaut team of STS-117 will install this new truss, unfold one set of solar arrays, and retract another.

The next major step will occur on May 23, when workers will start filling Atlantis with fuel. The 43-hour countdown will begin on June 5.

Original Source: NASA News Release

May 15, 2007December 26, 2015 by Fraser Cain

Progress 25 Docks with the Station

The latest Progress cargo ship sent to the International Space Station docked today, delivering much needed air, water, fuel and other supplies. It was launched from the Baikonur Cosmodrome in Kazakhstan on Friday morning, and took 3 days to match orbit with the station.

Progress 25 linked up to the aft port of the Zvezda Service Module on Tuesday morning while the station was above the northeast coast of Australia. The docking only took minutes, but now the hatch between the two craft will be slowly opened up overnight, so the astronauts can get to work unloading it.

On board Progress 25 are more than 476 kg (1,050 pounds) of propellant, 45 kg (100 pounds) of air, 420 kg (925 pounds) of water, and another 1,380 (3,042 pounds) of dry cargo.

Original Source: NASA News Release

May 15, 2007March 3, 2023 by Fraser Cain

Ring of Dark Matter Discovered Around a Galaxy Cluster

Astronomers using the Hubble Space Telescope have turned up a ghostly ring of dark matter, surrounding the aftermath of a collision between two galaxy clusters. This is one of the strongest pieces of evidence ever found for the existence of dark matter; a shadowy substance that only interacts with regular matter through gravity.

Researchers discovered the ring while they were mapping the distribution of dark matter inside the galaxy cluster Cl 0024+17, which is located about 5 billion light-years from Earth. The ring itself is 2.6 million light-years across.

Since dark matter is invisible, the researchers discovered the ring by its gravitational influence on background galaxies. The more dark matter concentrated into an area, the more the light from background objects is distorted, like ripples on a pond of water. We’re fortunate that the head-on collision between the galaxy clusters provided us with a perfect view from our perspective here on Earth.

So how did this ring form? Simulations have shown that when galaxy clusters collide, the dark matter falls into the centre of the combined cluster, and then sloshes back out. As it heads back out, mutual gravity slows it back down, and the dark matter piles up into a ring.

Original Source: Hubble News Release

May 15, 2007December 26, 2015 by Fraser Cain

Newly Discovered Planet Orbits in Just 31 Hours

Of the extrasolar planets astronomers have discovered, it’s the hot jupiters that really boggle the imagination. These worlds can be much larger than Jupiter, but tear around their parent star in just a few hours. Or in the case of newly discovered TrES-3, in just 31 hours.

This latest discovery, titled TrES-3: A Nearby, Massive, Transiting Hot Jupiter in a 31-Hour Orbit, will be published in an upcoming issue of the Astrophysical Journal Letters.

As with many planetary discoveries, this was a team effort, made by astronomers and observatories around the world. The story begins when astronomers measured a periodic dimming around parent star GSC 03089-00929 – a G-dwarf star 90% the mass of the Sun. Since the discovering instruments were part of the Trans-atlantic Exoplanet Survey (TrES) network, this is how the planet got its name.

Once the astronomers had a candidate, other astronomers performed follow up observatories using the Hungarian Automated Telescope Network, the Fred L. Whipple Observatory, the Submillimeter Array atop Mauna Kea, and a handful of other instruments around the world. By the time they were done, hundreds of observations had been made in many wavelengths.

It’s currently estimated to have a mass of approximately 1.92 the mass of Jupiter. As mentioned, it orbits its parent star once every 31 hours – at a distance of only 0.0226 AU (1 AU = the distance from the Earth to the Sun). That sounds fast, and it is. The current record is OGLE-TR-56b, which orbits every 29 hours. So TrES-3 comes in a close second.

Based on their observations, TrES-3 is not a grazing transit. In other words, the planet passes directly between the star and the Earth, fitting its disk entirely within the disk of the star at mid-transit. The transit itself takes only 1.3 hours to complete. This provides astronomers with a useful testbed for theoretical models of gas giants. Astronomers want to understand what happens to planets this close to their parent star; how their orbits decay, and rate of thermal evaporation from being so close.

And here’s the mystery. At this close distance to its star, TrES-3 must be going furious evaporation of its gas. Astronomers are wondering if a planet could form this close, and still be around billions of years later. Another possibility is that it formed further out, and was pulled in close over millions of years. TrES-3 is so close that its gravity tidally effects the star, modifying the rate at which its orbit decays, and confusing the calculations.

The astronomers are planning follow up observations of TrES-3 with the powerful Spitzer Space Telescope, since it’s an ideal candidate for attempts to detect reflected starlight. This will allow astronomers to measure the planet’s albedo, or reflectiveness.

Original Source: Arxiv Release

Thanks to Dr. Pamela Gay for helping me puzzle through some of the scientific language.

May 15, 2007December 26, 2015 by Fraser Cain

Astrosphere for May 15, 2007

Follow me as we travel around the astrosphere, finding cool blogs and websites.

First up. astrophotographer Damian Peach (who contributed many photos to What’s Up) has put together an animation of Mars images providing a full rotation of the planet. Thanks for Chris Lintott’s Universe for the link.

NASASpaceflight.com is reporting that most leaders of the space industry have signed a letter, requesting that Congress increase NASA funding by $1.4 billion. Let’s hope they’re successful.

Space Prizes would like you to know that there are efforts underway to try and help save NASA’s Centennial Challenges. It seems insane to me that one of the least expensive, most public-friendly things NASA has done recently would be on the chopping block.

You’ve read Tammy’s suggestions for what to see in the night sky this week, now here’s a similar list from Vern’s Astronomy Weblog. Now there’s no excuse. Head outside and look up.

Remember, the 3rd Carnival of Space is at my place this week. Send in your entries before Wednesday night, and I’ll get them in.

May 14, 2007December 26, 2015 by Fraser Cain

Cluster Sees Earth’s Bow Shock Crumple and Reform

ESA’s Cluster spacecraft were at the right place at the right time to encounter a very special event: the Earth’s bow shock – a wave that forms where the solar wind buffets the magnetosphere – breaking and reforming. This situation was predicted in theory more than 20 years ago, but scientists had never seen it happening in space, until now.

The event occurred on January 24, 2001, when the four spacecraft that make up the Cluster formation were flying at an altitude of 105,000 km above the Earth. Each spacecraft was separated by a distance of about 600 km, allowing them to see space weather events at different times and places. As they approached the bow shock region, scientists expected they’d see roughly the same thing.

Instead, each spacecraft saw large fluctuations in its readings. The magnetic and electric fields were breaking and then reforming further out, like waves build up and crash on shore, and then reform again further out to sea.

Although rare in the Solar System, these kinds of events are very common in the Universe. Photos from Hubble have shown bow shocks form when the intense radiation from young stars blasts into the surrounding stellar nebula.

Original Source: ESA News Release

May 14, 2007December 26, 2015 by Fraser Cain

Progress 25 Blasts Off for the Space Station

A new Progress supply ship (P25) blasted off for the International Space Station on Friday, carrying more than 2.5 tonnes of fuel, air, water and other supplies. The unpiloted ship is expected to link up automatically with the station on Tuesday, docking at the aft port of the Zvezda Service Module.

Once astronauts fully unload its cargo, they’ll fill it back up again with trash and other material from the space station. It’ll then undock and burn up through the Earth’s atmosphere on July 20, making the garbage disappear forever.

The Progress vessels are very similar to the piloted Soyuz spacecraft that the Russians use to launch cosmonauts, and serve as lifeboats for astronauts on board the International Space Station.

Original Source: NASA News Release