NASA, ESA, H. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team
Just to prove that amateur astronomers can and do make valid contributions to observing important goings on in the Universe. The impact on Jupiter was discovered by Australian amateur astronomer Anthony Wesley on Sunday 19 July 2009. The spot was created by a small object either a comet or asteroid plunging into Jupiter’s atmosphere. The last time this happened was on 16 July 1994, when comet Shoemaker-Levy 9 smashed into the gas giant and continued to bombard Jupiter until 22 July.
The Hubble team were lucky enough to be able to snap this image and at the time of the image the impact was twice the length of the United States.
The force of the impact on Jupiter is thought to be thousands of times more powerful than the suspected asteroid or comet that exploded over the Tunguska River Vally in Siberia during June 1908 and the object is thought to be the size of several football fields.
This image was taken with the Kitt Peak Mayall 4-metre telescope in Arizona (Image: Travis A. Rector/U of Alaska Anchorage/Heidi Schweiker/NOAO)
Check out the beautiful planetary nebula on the left. I have to admit when I first saw this I thought it was a camera trick or a photoshop image, simply because spherical nebulae are so rare.
The image was spotted on 6 July by a professional astronomer, Dave Jurasevich of the Mount Wilson Observatory in California and then a couple of days later by amateur astronomers, Mel Helm and Keith Quattrocchi.
This is one of the reasons why I love astronomy. As an amateur you can make a contribution regardless of your qualifications.
Credit: J.T. Clarke, G.E. Ballester (University of Michigan), and J.T. Trauger (Jet Propulsion Laboratory), and NASA
On the 16 July 1994 every one was watching Jupiter. No, Arthur C Clarke’s story about the monolith hadn’t come true. A comet was about to slam into the gas giant.
Comet Shoemaker-Levy 9 had been pulled into orbit around Jupiter. It’s speculated that this happened during the 1970’s. During it’s time in orbit around Jupiter, Comet Shoemaker-Levy 9 had been ripped apart by the formidable tidal forces of the planet.
No one was sure what would happen when the comet collided with Jupiter. There were suggestions of huge seismic waves rippling across the planet or perhaps the comet debris would behave like meteors do in our own atmosphere.
The Galileo space probe was in the perfect place to observe as the drama unfolded. As the first comet fragment struck the atmosphere of Jupiter, Galileo detected a fireball. Its temperature peaked at 24,000°C (43,232°F) and created a plume of disturbed gas 1,900 miles (3,000km) in height. Minutes later a huge dark spot came into view where the fragment had impacted.
The cometary fragments continued to bombard Jupiter until 22 July and the wounds on the planet were visible for months.
This dramatic event reminds us that Jupiters gravitational field is responsible for collecting many rogue bodies that wonder past it. This means that there’s less chance that the Earth is going to be hit by something that could destroy all life.
ESA’s Venus Express has mapped Venus’ southern hemisphere in infrared. The infromation provided by the new map suggestes that Venus may at one time have been more Earth like with plate tectonics and a liquid water ocean.
The map was compiled between May 2006 and December 2007 and consists of over a thousand individual images. Because of Venus’ cloud cover it’s not possible to use normal cameras as they cannot image the surface. To obtain the images Venus Express used a particular infrared wavelength to enable it to see through the clouds.
In the past radar systems have been used to provide high resolution maps of the surface of Venus. ESA’s Venus Express is the first spacecraft to produce a map that hints at the chemical composition of the rocks whilst still in orbit. The new data is consistant with the theory that the highland plateaus of Venus are ancient continents that were once surrounded by an ocean and were created by volcanic activity.
Credit: Left panel: X-ray (NASA/CXC/Durham Univ./D.Alexander et al.); Optical (NASA/ESA/STScI/IoA/S.Chapman et al.); Lyman-alpha Optical (NAOJ/Subaru/Tohoku Univ./T.Hayashino et al.); Infrared (NASA/JPL-Caltech/Durham Univ./J.Geach et al.); Right, Illustration: NASA/CXC/M.Weiss
NASA’s Chandra X-ray Observatory has been studying 29 gigantic blobs of hydrogen gas to ascertain the source of the huge amount of energy needed to make these structures glow. These strange globules are called ‘Lyman-alpha blobs’ by astronomers because of the light they emit and are several hundred thousand light years across. It’s also thought that they are only seen when the Universe is approximately two billion years old, or about 15% of its current age.
The composite image above shows one of the largest blobs observed in this study. The glowing hydrogen gas in the blob is shown by a Lyman-alpha optical image (coloured yellow) from the National Astronomy Observatory of Japan’s Suburu telescope. There is a galaxy located within the blob that is visible in a broadband optical image (white) from the Hubble Space Telescope and also an infrared image from the Spitzer Space Telescope (red). The blue image from the Chandra X-ray Observatory shows evidence of a growing supermassive black hole in the centre of the galaxy. The energy from this active black hole is enought to light up and heat the gas in the blob. It’s also thought that radiation and winds from rapid star formation occuring in the galaxy have a similar effect. There is also evidence of another four active black holes in the blobs.
The image top right shows an artist’s impression of what a galaxy may look like inside a blob when looked at from fairly close range.
Salty ice has been discovered on Saturn’s moon Enceladus. The moon replenishes the ring with material from discharging jets and it’s thought that the moon could harbor a reservoir of liquid water, perhaps an ocean, beneath its surface.
The Cassini spacecraft discovered the water ice jets in 2005 on Enceladus. These jets eject tiny ice grains and vapour, some of which escape the moon’s gravity and form Saturn’s outermost ring. Cassini’s cosmic dust analyser has examined the composition of those grains and found salt within them.
The scientists working on Cassini’s cosmic dust detector conclude that liquid water must be present because it is the only way to dissolve the significant amounts of minerals that would account for the levels of salt detected. The process of sublimation, the mechanism by which vapour is released directly from solid ice in the crust, cannot account for the presence of salt.
The outermost ring particles are almost pure water ice, but nearly every time the dust analyser has checked for the composition, it has found at least some sodium within the particles.
However, researchers doing ground-based observations did not see sodium, an important salt component. The ground-based observation team notes that the amount of sodium being expelled from Enceladus is actually less than observed around many other planetary bodies. These scientists were looking for sodium in the plume vapour and could not see it in the expelled ice grains. They argue that if the plume vapour does come from ocean water the evaporation must happen slowly deep underground rather than as a violent geyser erupting into space.
Determining the nature and origin of the plume material is a top priority for Cassini during its extended tour, called the Cassini Equinox Mission.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.
You can find out more information at either ESA or NASA
NASA’s last mision to the moon, Clementine produced images like this (on the left).
Unfortunately a malfunction in one of the onboard computers cut short the mission which ended on June 1994 due to the telemetry from the spacecraft being inteligible.
Credit: NASA/Goddard Space Flight Center/Arizona State University
This is one of the latest images sent back by NASA’s Lunar Reconnaissance Orbiter (LRO). The orbiter has taken images of a region in the lunar highlands south of Mare Nubium (Sea of Clouds)
As the moon rotates beneath the orbiter photographic maps of the lunar surface will be gradually built up.
The first images have been taken along the moonsdividing line between day and night (it’s terminator) and because of the deep shadow subtle topograpy has been exaggerated.
