August 1, 2010
Right now, the Earth is passing through fragments and dust trails created by the Comet Swift-Tuttle and this means the Perseids Meteor Shower has begun and will be getting stronger each day and it will peak from August 11-14. Lewis Swift and Horace Parnell-Tuttle discovered the Swift-Tuttle Comet in July of 1862. The comet passed by Earth in 1992 and will not return again until 2126, however the dust left behind by this comet creates a dependable annual meteor shower, the Perseids. The Perseids is named after constellation Perseus because meteors seem to spread out from an area surrounding the constellation, this is called the radiant.
The Perseids Meteor Shower will peak in the morning of August 12, meteors can be seen anywhere in the sky. The main thing to viewing any meteor shower is to find a safe, dark place away from man-made lights and lean back in a relaxing position looking toward the darkest part of the sky. Sometimes the Moon can be a hindrance, but this year the Moon will not be shedding much light, as during the peak it will be a waxing crescent Moon phase, so this means more visible meteors.
It is predicted that The Perseids Meteor Shower is going to have some great activity this year, up to 100 meteors per hour! It promises to be the best meteor shower this year. The meteors (shooting stars) are produced when debris left behind by a comet ranging from, as big as grains of sand to the size of a pebble, enter the Earth’s atmosphere with speeds reaching, 70 kilometres per second, and burn high up in the atmosphere due to friction and vaporise which causes them to glow brightly. A lot of junk hits our atmosphere so a good way to find out if you’re looking at a sporadic meteor or one from Perseids is to find where it originates from, if its moving away from the radiant it probably belongs to Perseids, if it’s going towards the radiant it’s a sporadic one, it’s always a good idea NOT to look directly at the radiant, as most meteors are going away from it. If you’re unlucky and have cloudy skies, don’t’ worry, you can hear the meteors! Just take an old radio out and tune it to the lowest frequency and you can hear the meteor echoes which sound like this. You can find more about meteor echoes here.
Meteor showers are one of the most spectacular astronomical events and it’s really easy to catch them, all you have to do is go out and look up, you don’t need anything but a dark clear patch of sky! And like most outdoor activities it’s best when you share the experience with your friends and family, the more eyes you have on the sky the more chances you have of catching the meteors streak across. I have a deep connection with meteor showers, when I saw my first one, it mesmerised me and inspired me to learn more about the sky above!
The Perseids Meteor Shower promises to be one of the best meteor showers of the year with lots of meteors streaking across the sky, you should definitely go out and see it!
July 12, 2010
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From Cassini, 1,460,000,000 km away, comes this great image of the majestic rings of Saturn lit up brightly by the Sun. This is a raw image, it hasn’t been processed, that spot in the middle of the image is probably a cosmic ray hit.
Saturn’s rings are not a simple disk, but it is actually made up of thousands of separate rings. The big dark gap in the rings is called the Cassini Division, discovered by the astronomer Giovanni Domenico Cassini in the 17th century. Saturn’s moon Mimas is responsible for that gap; any particle in the Cassini Division orbits Saturn in half the time Mimas does, and so it feels a periodic tug from the moon (called a resonance). That pulls the particles clear from that region, carving a gap. Other broad gaps in the rings are from other moon resonances, while some of the narrow ones are from small moons in the gaps gravitationally clearing out nearby ring particles.The rings are made up of icy particles,they range in size from, about a grain of sand to the size of a small house, but on average they are the size of your clenched fist. The rings extend from about 74,000 kilometres to about 180,000 kilometres from Saturn’s centre, but they are very thin, less than a hundred metres thick! A scale model of the rings as thick as a single piece of tissue paper would cover an entire football field! It’s still unclear how Saturn, or the other three gas giants, got their rings, but there is more than one mechanism to get them, a moon could get hit by an asteroid or comet shattering it.
There’s a lot we don’t know about Saturn and its rings, but Cassini has been orbiting Saturn for a while, it’s taken some amazing images of Saturn and everything around it. Cassini is helping us solve the mysteries of the Saturn and its surroundings in far better detail than ever before. It has produced some of the highest resolution images of the ringed planet and its moons.
You can scour the Cassini image gallery yourself, click here.
July 9, 2010
The sample canister of Hayabusa, the troubled probe which had a dramatic re-entry back in June, has now been opened and it has some material in it! This is great news! Due to malfunctions it wasn’t clear if the probe managed to collect material from the rubble pile asteroid Itokawa, but JAXA has found a very small amount of dust particles in the container. It isn’t clear if the dust grains which are very small, about 0.01-millimeter in size, are from the asteroid itself, or if it could be from Earth — left in the container from before launch, or it possibly could have made its way in there during the landing/post landing handling. “Material on the planet or asteroid or particulate matter is at this stage is unknown, we will consider in detail,” is the Google translate version of the JAXA press release. The image above was taken on June 28, 2010, and below is a magnified view of one of the particles.
This magnified view was taken on June 29, and shows a magnified view of one very small particle being picked up by a quartz manipulator, which appears as a stripe on the image. It will take several weeks to confirm whether the particles are from the asteroid, but if so, would be the first-ever asteroid sample return.
What do you think about this? Do you think Hayabusa brought some asteroid dust back? Or maybe we can just ask Paul the Octopus! Leave a comment!
From Doug Wheelock’s Twitpic page, an astronaut on the International Space Station (ISS), comes this brilliant image of the Southern Lights (Aurora Australis) as seen from the ISS.
The northern (Aurora Borealis) and The southern (Aurora Australis) are caused when the charged particles (ions) from the Sun hit the Earth. The ions from the Sun excite the electrons of the atoms in the atmosphere which in turn emit a photon (light). Different atoms release light in different colours, the greenish colour seen here is emitted by oxygen atoms.
Doug Wheelock has some out of this world pictures on Twitpic page, check it out!
June 14, 2010
After long and treacherous journey the Japanese probe Hayabusa has returned to Earth safely. It put a spectacular show over the Australian outback, making a fiery re-entry. In the video of the falling debris shot from a DC-8 plane you can see a speck: that speck is the sample return canister which, hopefully, contains some material from the asteroid Itokawa. It was separated three hours before reaching Earth via parachute. The canister has been recovered successfully, it is in good condition and it has been taken back to the Japanese scientist, who will find out if there is anything in the canister. JAXA has said that it is going to share the material with scientists around the world. They say that even if it contains one grain of material it can be cut up into 100 or more samples and distributed to scientists around the world.
The probe was scheduled to return in 2007 but due to several problems the arrival date was pushed back to 2010. JAXA is not sure if it managed to collect a sample but even a grain of material would be a great achievement and it will give us some insight about asteroids and it might tell us something about our past. It is speculated that early asteroid impacts may have seeded Earth with materials to form life, but it is unlikely that something like that will show up in the materials collected, it’s too early to say anyhing. For now, we can keep our fingers crossed and hope that it managed to collect some material from Itokawa, a potato shaped ball of debris and rocks held together by gravity.
If something like that was headed towards Earth we would want to know as much about it as possible.