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Surprise meteor, Hubble service mission update and China’s lunar probe March 2, 2009

Posted by Mike Trudeau in Astronomy, Nasa, Space.
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Woah! What the hell was that? A totally unexpected asteroid sped by on Monday between the Earth and the Moon. It’s travelling at twenty kilometres per second and is between 60 and 100 metres wide. Apparently that’s nothing new, and a lot of asteroids zip by unnoticed. I find that a little unnerving.
The difference between an asteroid and a comet (like the comet Lulin that passed by last week) is in their appearance. Comets have a visible tail (or coma) and asteroids do not. A comet’s tail is water vapour and dust particles that have blown off the body of the comet as it gets close to the sun.
A meteoroid is smaller than an asteroid (and according to the official definition, bigger than an atom). It becomes a meteor when it enters a planet’s atmosphere and becomes visible as a bright streak. Any material from a meteor that makes it to the ground becomes a meteorite.

In other news it looks like the upcoming service mission to the Hubble space telescope will get the go-ahead after all. After the recent satellite collision there had to be some weighing of the risks. If the mission succeeds it would make the Hubble much more powerful and extend its life considerably.

Finally, China’s Chang 1 lunar satellite concluded its mission of mapping the surface of the moon by slamming into the moon in a “controlled collision.” Although it only became the third country to send a person into space recently, it looks like China is pursuing its space program ambitiously, with plans for a space station and manned lunar mission in the works as well.

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Let It Snow February 20, 2009

Posted by Mike Trudeau in Space, What?.
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Before I talk about China’s power to control the weather, I have an update on the space junk situation.
Nasa is currently considering if it will be safe enough to send the shuttle up for Service Mission 4 to the Hubble Telescope after the satellite collision earlier this week. Scientific American has some good speculation about ways of clearing the skies, and says that the mission will go ahead as long as there is seen to be less than a one-in-sixty chance of debris hitting the shuttle. Cosmic Variance bets that if the mission is cancelled, Nasa might try sending robots instead. I’m not so sure…why wouldn’t they have just sent robots in the first place?
They also link to a webcomic letter to the notorious Higgs Boson, which Large Hadron Collider hopes to find when it’s powered up later this year. Apparently the gloves are off and the Tevatron at Fermilab in the States is saying they’ve got a 50% chance of finding the Higgs first if the LHC can’t power up soon enough. Any bets?

In other news, China claims to have triggered a snowfall over Beijing by firing iodide sticks into the clouds. According to the Chinese Weather Modification Command Centre (I kid you not), the iodide sticks give below-freezing water droplets something to freeze around, resulting in snowfall. I get the impression that the effectiveness of this method hasn’t been proven yet…also, the press seems to be misrepresenting it a little bit because in order to create the snowfall, the moisture needs to already exist in the clouds. So, it looks like the drought might have been coming to an end anyway. There’s some funny video footage at the Times (Oh, communists!) and Reuters has an article about how the government had to close twelve highways due to the snow.
Here’s an interview with an expert at Scientific American, as well as this REALLY hokey youtube video where some babbling weatherman tries to explain it.

Facebook warning and Hubble/Kepler update February 18, 2009

Posted by Mike Trudeau in Space, Technology, The Internet.
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Before anything else, I recommend you go into your Facebook account and change your privacy settings. here is an article about Facebook’s recent changes to its terms of service (that thing you say you’ve read and understand before you get your account) that supposedly means Facebook permanently owns all the rights to your photos and notes etc. Here is Facebook’s reply, that claims no such thing. I still changed my privacy settings and you should too.

I came across this diagram to give you the idea of how much space junk is orbiting at what altitude, along with other functioning space objects like the Hubble. The accompanying article raises the point that even if there is no direct threat of debris hitting the Hubble or the ISS, there is still the risk that clouds of debris produced by the recent collision could prevent the upcoming Service Mission 4, scheduled for May 12 2009. The aim of the mission is to repair several of the telescope’s systems and install some new hardware that would hugely increase its abilities. Without this mission there would not be a lot of hope left for Hubble’s continuing operation.

Speaking of space telescopes, the BBC ran an article describing how the Kepler Space Telescope will work. I had no idea that the area of sky visible to the Hubble is only as much as would be covered by a grain of sand held at arm’s length! That’s tiny! In comparison, Kepler will be able to look at an area about the size of your hand at arm’s length. Also, its cameras are much more powerful.

The article says we can hope to see our first results within three months or so of launch, but that finding an Earth-sized planet will probably take several years. Now I know everything space-mission-oriented takes a long time, but I’m also very impatient…

The telescope is named after the father of celestial mechanics, Johannes Kepler. Basically he discovered a lot about planetary motion, which is captured in these beautiful and intricate mechanisms called orreries. Check’em out!

Satellites Collide February 17, 2009

Posted by Mike Trudeau in Space, The Future.
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Two satellites collided in low Earth orbit last week, prompting worries about the likelihood of other space collisions as the number of orbiting satellites grows.
There are a lot of bits and pieces floating around up there, and they are all moving at incredible speeds. For example, a while ago the space shuttle suffered a half-inch crater in its windscreen from nothing more than a paint chip. This paint chip was travelling at more than twenty thousand miles an hour.
What worries me is this: The two satellites exploded into two clouds of debris that orbit the Earth, gradually becoming rings. Now it’s much more likely for another satellite to travel through one of those rings and be hit by shrapnel big enough and fast enough to destroy the satellite, leading to a new ring of debris and increasing the chances of collision even more. This is called a cascade effect, in which a single event can lead to an accelerating chain of other events, with huge consequences. Imagine dropping a single grain of sand on a sand dune. It hits two grains, they hit four grains, and on and on until you have a sizeable landslide. It’s that kind of thing. The more garbage you have up there, the harder it will be for satellites to avoid becoming clouds of garbage themselves. This could have severe consequences, considering how much of our communications technology relies on satellite relays. Let alone the risk for big guys like the Hubble Telescope or the International Space Station.
The New Scientist talks about it in this good article.

Finally fans of informed speculation should check out this website. It’s a collection of intellectuals and experts from various fields answering the question “What will change everything?”
Especially check out George Dyson’s article on interstellar viruses.

So long for now.