Scientists celebrated this week after finally seeing ghostly spokes in Saturn's rings. These spokes were first discovered by NASA's Voyager spacecraft 25 years ago, but so far, Cassini had failed to image them. These spokes are about 2,500 km long and 100 km wide (2,200 miles by 60 miles), and are believed to be created by Saturn's magnetic field interacting with the rings. Scientists thought that the visibility of the spokes depended on the angle of Saturn's rings to the Sun; the less sunlight, the easier it should be to spot the spokes.
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Cassini has taken images of what seems to be an ancient shoreline cutting across Titan's southern hemisphere. The shoreline runs about 1,700 km long by 170 km wide (1,060 miles by 106 miles) and might still have liquid present. There is evidence for networks of channels that feed liquid - most likely liquid hydrocarbons - into this "ocean"; some might come from springs, while others will have to have been fed by rainfall. Cassini's next flyby is set for October 26, 2005.
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Some people dream in black and white while others dream in techni-colour. Daydreamers wander the realm of possibilities just as well as the sleepers. Subjects of dreams differ as greatly as the dreamer. Engineers, particularly astro-engineers, probably have recurrent dreams of launching into a project destined for the stars. Well, if dreams don't come true, there's always the pen and paper. That's how the book
The Rocket Company by Patrick Stiennon and David Hoerr seems to have risen. Using the literary licence of a fictional company, the authors bring a wealth of non-fictional detail to a pleasant little dream.
Greetings, fellow SkyWatchers! Let's begin the week early in the morning by watching Saturn dancing near the "Beehive", move into the night with the ISS and a great a variable star - Eta Aquilae. As the skies darken this week, we'll return to the Andromeda galaxy and hunt down the M30. Have you ever seen the "Saturn" or "Helix" nebulae? Don't think them too difficult to find, because a few simple tricks will turn you into a pro and you'll find Neptune as well! Hang on, it just gets better as the Aurigid meteor shower peaks and a new comet joins some old favourites. So turn your eyes to the skies, because...
Here's what's up!
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NASA has unveiled more details about its upcoming series of missions to return humans to the Moon as early as 2018. The new crew vehicle will look very similar to the old Apollo module but it will be three times larger, allowing four astronauts to travel to the Moon at a time. Each ship can be reused 10 times, and NASA hopes to get as many as 2 launches a year, with astronauts spending 4-7 days on the surface. Eventually, once a lunar outpost is built at the southern pole, astronauts will be able to live on the Moon for 6 months at a time.
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Planets in the inner Solar System suffered two devastating periods of asteroid bombardment. Scientists are fairly certain that the early period came from asteroids identical to the space rocks in the current main belt between Mars and Jupiter. The second period is a bit of a mystery, though. Scientists now think that there was a period at the end of planetary formation when the giant planets swept up leftover material and hurled much outwards, but also some towards the inner Solar System.
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Researchers have had a few months to crunch through the data collected during Deep Impact's collision with Comet Tempel 1. The latest research published in the Journal Science used findings from three giant telescopes atop Mauna Kea in Hawaii. The observations determined that as much as 25 fully-loaded tractor trailer-trucks worth of material was excavated out by the impact. The comet seems to have a complex mix of silicates, water and organic compounds beneath its surface.
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NASA has two new Earth Observation satellites in the final stages of preparation before their launch: CloudSat and Calipso. The two satellites will be launched together by a Boeing Delta II rocket from Vandenberg Air Force Base in California. They will be launched into a polar orbit, and maintain a close formation. CloudSat has an extremely powerful cloud-profiling radar, which can distinguish between cloud particles and precipitation. Calipso will be able to detect aerosol particles in the air, and can tell the difference between these particles and clouds to measure the amount of air pollution. They may launch as soon as October 26.
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Since it's in my neighbourhood, globally speaking, I thought I'd mention that the Dominion Radio Astrophysical Observatory, which is located in Southeast British Columbia, will be having an
open house on Saturday, September 24. They've got a 26-metre radio dish, and many other instruments. It would be a great opportunity to see the equipment and meet radio astronomers, so if you live nearby, put this on your calendar. (Unfortunately, I won't be able to attend... maybe next year).
Fraser Cain
Publisher
Universe Today
Japan's Hayabusa spacecraft arrived at Asteroid Itokawa earlier this week, and now it's sending back beautiful images. This image is a composite colour image of the asteroid taken on September 12 using red, green and blue filters. It's also possible to see its irregular shape. Hayabusa will eventually land on the surface of Itokawa, collect samples to be sent back to Earth. The probe's sample return capsule is expected to return to Earth in June 2007.
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A team of Canadian engineers have developed a tiny 3.5 kg satellite that could unleash a whole new industry of microsatellites. The Canadian Advanced Nanospace eXperiment 2 (CanX-2) is about the size of a shoebox, but it packs a mini-spectrometer that will measure greenhouse gasses - for only $1 million in development costs. Future missions will hope to demonstrate how fleets of inexpensive microsatellites might be able to serve the same function as satellites that cost hundreds of millions of dollars to design and manufacture.
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The Hubble Space Telescope has discovered a supermassive black hole without a surrounding galaxy. These black holes and their galaxies are usually linked, so it's an unusual discovery. One possibility is that the host galaxy was stripped away during a collision with another galaxy. Another possibility is that the black hole is surrounded by a large amount of material, it's just dark matter, so Hubble couldn't detect it.
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In preparation for its arrival at Mars next year, NASA has begun putting the Mars Reconnaissance Orbiter through its paces. Controllers pointed its three cameras at the Moon and the stars, They also tested the spacecraft's onboard Context Camera and Optical Navigation Camera, and also its high-gain antenna for transmitting back to Earth. MRO was able to send back 75 gigabits of data in less than 24 hours, which is a new record for communicating with a spacecraft. It will enter Mars orbit on March 10, 2006.
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A recent
conversation on the Bad Astronomy/Universe Today forum got me thinking. Member "parallaxicity" wanted to know where the next generation of unmanned probes should be sent. Should we investigate Europa, and dig through its icy skin? Or what about building a blimp that could float in Titan's thick atmosphere analyzing the surface in incredible detail? Let me just wipe the drool from my chin; some of these missions would be so cool. But you know, I'll have to take a pass. Right now, I think we need to focus on one thing...
Researchers at Washington University in St. Louis have used primitive meteorites called chondrites to develop a model of the Earth's early atmosphere. And it looked nothing like what we have today. Instead of the familiar oxygen and nitrogen, our early atmosphere would have been a toxic mixture of methane, ammonia, hydrogen and water vapour. Simulating this early environment was actually quite difficult to calculate because the minerals of the early Earth reacted to the hot environment in hard-to-predict ways.
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Cassini scientists have assembled this mosaic image of a region on Titan called Fensal-Aztlan. The northern part of the region, "Fensal", has small islands which range in size from 5 to 40 km (3 to 25 miles) across, while the southern "Aztlan" region mostly lacks these islands. The "islands" are thought to be raised areas of water ice, surrounded by dark particulate material which came out of the atmosphere.
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The Planetary Fourier Spectrometer (PFS) on board the ESA's Mars Express spacecraft malfunctioned a few months ago, and the agency wants to know why. The instrument was working perfectly for two years, and made the surprising discovery of methane in Mars' atmosphere. It might be malfunctioning because of spacecraft vibration, but the source of the problem is still under investigation. Even if engineers can't get the instrument working again, the spacecraft still has another 6 which are working fine.
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Although astronomers have discovered plenty of comets, they've always thought it was just a fraction (less than 3%) of the number of comets out there - and one of them might have our names on it. Fortunately, this scenario doesn't seem so likely, according to new research from scientists at the Australian National University, astronomers have probably found more like 20% of comets. That means that small comets, capable of destroying a city, probably only hit the Earth once every 40 million years, and big continent-busting comets probably only hit us once every 150 million years.
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The Hubble Space Telescope used its Advanced Camera for Surveys to capture this beautiful photograph of the Boomerang Nebula. This cloud of dust and gas has two nearly symmetric cones of material coming out of it. It was created through a process called bipolar outflow, where a dying star ejects material as it spins. It could be that the star is surrounded by a disk of dust, so only the top and bottom material can escape, or a powerful magnetic field is shaping it as it escapes.
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Down here on Earth we're protected by our planet's magnetic field from harmful radiation, but out in space, it gets a lot more dangerous. One particularly dangerous region are the Earth's Van Allen belts which astronauts have to pass through to get to the Moon and beyond. Researchers working in Antarctica have observed two rare space storms which drained electrons out of the Van Allen belt, and reformed it closer to Earth in a region that was thought to be free of radiation. This research will help scientists predict what kinds of solar storms will move this radiation around, and give astronauts time to prepare if they're caught in the open.
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An unpiloted Progress cargo ship docked to the Zvezda module of the International Space Station on Saturday, delivering supplies to the crew of Expedition 11. The supplies include food, water, fuel, oxygen, air, clothing and experimental hardware. Also on board are spare parts for the Russian Vozdukh carbon dioxide removal system and the Elektron oxygen generator. The astronaut will try and repair the Elektron next week to bring it back into service.
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Greetings, fellow SkyWatchers! This week is a sure sign of the Fall season as we welcome back the "Harvest Moon". While Selene will be the major focus of our studies this week, we can still take the opportunity to enjoy double star Gamma Delphini, find out why Vega is so "hot", and have a look at variable Beta Lyrae. So, head out under the moonlit skies, because ...
Here's what's up!
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What is your computer doing when you're not using it? If your answer is "nothing", then you need to put it to work in the name of science - finding aliens, detecting gravity waves, or predicting asteroid paths. Join the
Universe Today and Bad Astronomy team, and compete with other teams worldwide to see who can help crunch the most data. We'd love to get your help.
September arrives and with it come all the sweet memories of anticipation, trepidation and expectation of new school years. These days, I relive these feelings through my children but many of my own emotions still lie close to the surface. There won't be any astronomy texts yet for my two young ones, but others may find on their list the introductory text by Andrew Fraknoi, David Morrison, and SidneyWolff entitled
Voyages to the Stars and Galaxies. For those so fortunate, a good memory may be more practical than a sweet memory, for this book is chalkfull of pertinent astronomical information.
How will the Universe end? Right now cosmologists have two equally distressing scenarios mapped out for the long term fate of the Universe. On the one hand, gravity might slow down the expansion of our Universe so that it coasts to a stop and possibly even collapses back down into a Big Crunch. On the other hand, the expansion of the Universe could continue indefinitely thanks to the acceleration of dark energy. We would face a cold, lonely future as other galaxies fade away into the distance. My guest today is Eric Linder from the Lawrence Berkeley National Laboratory and he's proposing experiments that could help us learn which of these two fates await us.
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Saturn's moon Titan has long held a special fascination to astrobiologists. Its thick atmosphere is largely composed of nitrogen and organic molecules which are the building blocks of life. At a frigid -178 C (-289 F), however, it's much too cold to support life. But there could be some habitable locations on Titan, you just have to look carefully. Methane clouds around Titan indicate that it probably has an active cycle similar to the water cycle here on Earth. There could be areas where get warm enough on Titan for life to gain a foothold.
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The time frame for the formation of new planets appears to be getting shorter than previously believed. Astronomers have discovered gaps in protoplanetary disks that suggest there are gas giants forming there. One star, GM Aurigae, is a younger version of our own Sun and the gap in its disk is at about the same location as our own gas giant planets. Since GM Aurigae is only 1 million years old, these results challenge the traditional theories that planets slowly formed over many millions of years.
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An Italian team of astronomers have found a gamma ray burst that blew up 12.7 billion light-years away - the most distant ever seen. Astronomers have calculated that it exploded with 300 times more energy than our Sun will put out in its entire 10+ billion year lifespan. The blast was discovered by NASA's Swift satellite, which is dedicated to discovering these powerful explosions.
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Astronomers have spotted a dusty disc around an old, dead star. This star is similar to what our own star will look like billions of years from now. What's unusual, however, is this dust cloud. It should have disappeared long ago; either sucked into the star, or blasted away by intense radiation. One theory is that a planet is still orbiting the dead star, and is continuously shedding material to create this dust.
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The frame-filling view of Saturn's moon Rhea was taken by Cassini on August 1, 2005. Although in this image, Rhea looks quite similar to our Moon or the planet Mercury, it's actually covered in thick ice which would melt if it ever got as close to the Sun as Mercury. Rhea is 1,528 kilometers (949 miles) across, and you can see one of its larger craters, Izanagi, near the middle of the moon.
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When humans return to the Moon in the next decade, they'll be facing a dangerous combination of cosmic rays and solar flares. Astronauts will need to avoid getting too much radiation, so NASA is working to better understand risks. The upcoming Lunar Reconnaissance Orbiter (LRO) will carefully measure and map the Moon's radiation environment. It will also have a special instrument designed to simulate how this radiation will affect the human body.
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When Deep Impact excavated a crater in Comet Tempel 1, it released a spew of material that has existed since our Solar System first formed, billions of years ago. By analyzing this material, scientists have come up with better recipes for how to make planets, comets and asteroids. They were expecting to see water ice and silicates, but they were surprised to see materials like clay and carbonates (ingredient in seashells), since it was believed they required liquid water to form.
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John Chumack took this picture of the crescent Moon and Mercury from Dayton, Ohio. John used a Canon 10D and 180mm lens at F5.6 on 400ISO for 1 sec. exposure while mounted on a tripod.
Do you have photos you'd like to share? Post them to the
Universe Today astrophotography forum or
email them to me directly, and I might feature one in Universe Today.
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NASA and Sandia National Laboratories have been using a powerful solar tower to test new spacecraft materials. The tower reflects and focuses the Sun's radiation to blast spacecraft shields with the equivalent of 1,500 suns. This research effort is tied to a potential future mission to Saturn's moon Titan, which orbits in a very high-radiation environment. They have mimicked Titan's nitrogen-rich atmosphere for the tests, and the shield materials seem to have passed with flying colours.
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Researchers at the Washington University in St. Louis have developed a "field guide" for planet hunters searching for other Earths. They modeled the chemistry of silicate vapour and steam rich environments, similar to the early stages when an Earthlike planet is forming. During this stage, the planet is covered with a magma ocean which vapourises. This is a very distinct moment in the lifetime of a planet, and should be detectable because silicon monoxide gas is easy to see in infrared and radio wavelengths.
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New observations from the Hubble Space Telescope indicate that the largest asteroid in the Solar System, Ceres, might have huge reserves of water ice under its surface. Ceres is approximately 580 miles (930 kilometers) across, and resides with many other asteroids in a belt of material between Mars and Jupiter. Ceres' crust shows evidence of water-bearing minerals. In fact, if Ceres is 25% water, it would have more fresh water than what we have here on Earth.
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This is an image of the Biblis Patera volcano's caldera which was taken by the ESA's Mars Express spacecraft. Biblis Patera is nearly 170 km (106 miles) long, 100 km (62 miles) wide, and its summit is 3 km (1.9 miles) high. The bowl-shaped caldera might have formed when a magma chamber collapsed during an eruption of the volcano.
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Even though Deep Impact smashed into Comet Tempel 1 several months ago, scientists are still analyzing the data gathered before and after the collision. Very few close up pictures of comets have ever been taken, so the data gathered by Tempel 1 is very valuable, and sometimes surprising. The nucleus of Temple 1 has layers that show in topographic relief, ranging from smooth surfaces to impact craters. It's also extremely porous, which allows the surface to heat up and cool down almost instantly when hit by sunlight.
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Cassini has found that Saturn, like the Earth, has many different kinds of clouds. Some are hazy bands, high up in the planet's atmosphere, while others seem to go much deeper. These deeper clouds live about 30 km (19 miles) under the cloud surface and seem to be isolated features that have different shapes, like ovals, donuts, and swirls. There are also dozens of "lanes" which go completely around the planet, similar to the bands which can be seen in many telescopes, but are much narrower.
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Greetings, fellow Sky Watchers! While the Moon will figure prominently in our studies this week, let's start off with telescopic challenge - "Barnard's Galaxy". Do you only have binoculars? Don't worry, the NGC 6871 will surely please you. If you have eyes, then you're in luck as the Moon, Jupiter, Venus and Spica dazzle the western skyline and Piscid meteor comes to call. So, get thee out under the stars and in the moonlight, because...
Here's what's up!
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Cassini scientists have announced a host of new findings about Saturn's rings, including some new knotted structures in the planet's F ring. One of the major discoveries is that parts of Saturn's D ring (its innermost ring) have relocated and dimmed. In fact scientists have been able to track fairly significant changes between when Voyager first visited Saturn 25 years ago. The delicate G ring seems to contain faint arcs, which might be hiding additional planets. And most surprisingly, knots in the planet's F ring seem to be arranged like a coiled spring winding around the planet.
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The ESA's Integral space observatory and NASA's Rossi X-ray Timing Explorer spacecraft have found a rapidly spinning pulsar in the process of consuming a neighbour. This discovery supports the theory that pulsars spin so quickly because they pick up material from a companion, which increases their mass. Pulsars were once stars more than 8 times as large as our Sun, but their intense gravity compacted them down to a size of about 20 km (12 miles) across.
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In this photograph taken by Cassini, you can see the faint moon Pandora moving through Saturn's F ring. As a shepherd moon, Pandora and its partner Prometheus confine and shape the main F ring with its gravity. Pandora is 84 kilometers (52 miles) across. This image was taken on August 2, 2005, when Cassini was approximately 610,000 kilometers (379,000 miles) from Pandora.
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There's a long chain of events that led from the collapse of our local cloud of gas and dust to the evolution of life here on Earth. Exactly how each of these steps unfolded is still a bit of a mystery, but scientists know that a few atomic combinations were necessary: water, and organic compounds containing carbon. Dying stars are the source for this carbon, which they belch out, creating a kind of carbon soot. From there, this soot is blasted by intense radiation to create more than 100 different molecules, including fatty acids and simple sugars.
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