On its epic journey to Endeavour Crater, Mars Expedition Rover (MER) Opportunity passed a suspect looking boulder on July 18th. Dubbed “Block Island” by MER controllers, this dark rock looks very different from its surroundings, so Opportunity has been ordered to go off its planned route by 250 meters and have closer look.
Measuring approximately 0.6 meters across, the jagged specimen could be a meteorite, giving the rover a chance to carry out an in-situ analysis of its composition, determining whether or not this is indeed of extra-martian origin.
The next step is for the rover to extend its robotic arm, pressing the Alpha Particle X-Ray Spectrometer (APXS) up against the rock’s surface. The spectrometer will basically give the sample a blast of radiation, consisting of alpha particles and X-rays. The analysis of scattered alpha particles (after they have bounced off the material) will reveal the mass of the elements they collide with and the emission of X-rays will also reveal a lot about the material.
So could this be a meteorite? We’ll have to wait until the little robot has carried out its experiment… she may be getting old, but Opportunity is still carrying out some awesome science.
Earth has been hit numerous times in recent months by some large chunks of space rock. One of the larger meteoroids to enter the atmosphere was the November fireball over Saskatchewan, Canada. In this case, an estimated 10 tonne meteorite slammed into the atmosphere, creating a bright bolide (fireball), exploding into fragments. Fortunately, eyewitnesses were able to pinpoint the location of possible debris. Sure enough, after an extensive search in the rural area of Canada, meteorite fragments were found.
However, these fragments did not impact the ground at the hyper-velocities that the original fireball was travelling at, the Earth’s thick atmosphere created an efficient barrier, through air resistance, breaking up the bolide. In this case, an energetic explosion was observed for miles around. Fragments from the fireball then fell at a maximum speed of terminal velocity, bouncing off the ground. Some fragments sat proudly on top of frozen ponds – the debris final kinetic energy was so low that little damage would have been done even if the small rocks scattered over a populated area (unless, of course, someone got hit on the head – they would have had a very bad day).
OK, so we’re well protected from most bits of junk space can throw at us. Most meteoroids, from the size of a grain of sand to the size of a small bus, will burn-up, break-up or explode high in the atmosphere, scattering bits on the ground. But what about Mars? What if Mars gets hit by a sufficiently-sized meteoroid?
Even if the meteoroid does break apart, unfortunately the atmosphere is too thin to slow the debris sufficiently. A lack of air resistance makes for more impressive impact craters. Watch your heads future Mars colonists, you could be faced with a shotgun blast from space… Continue reading “Mars Gets Hit By Cosmic Buckshot”
Just when we thought it was getting quiet, a fireball exploded over Scandinavia last night. What’s more, there is outstanding video footage of the event over the skies of Sweden (above). There are a huge number of sightings from Sweden, Denmark and Holland which is good, there’s a better chance of finding any debris that way (in fact, if you saw something, contact the International Meteor Organization).
“The fireball occured on January 17th at 19:09 UT. It was a spectacular sight. Duration: 3 or 4 seconds, colours: yellow to green, fragmentation yes, brightness -10 or maybe brighter. I’m a meteor observer active since 1978 and I have observed almost 60 000 meteors since that time.” – Koen Miskotte, Ermelo, Netherlands.
Update (16:00 PST Dec. 14th): Eyewitness accounts are becoming more detailed, if you were in the Auckland area at 10pm (December 13th) and you saw something, please let me know (by leaving a comment below). Please give as detailed an account as possible, including your location and the direction at which you saw the meteorite. Hopefully we’ll piece this event together…
A fire erupted in an Auckland warehouse shortly after several eyewitness reported seeing a meteorite over the North Island of New Zealand. One witness (named “Mike”) even went as far to say that he watched the fiery object hit the Ponsonby area of the city, followed by an exploding noise.
The time of the several eyewitness reports (not amateur astronomer reports I want to point out) and the start of the blaze appears to correlate (although the local media is a little sketchy about the details at the moment). Apparently the fire caused serious roof damage to the warehouse and there was one minor casualty (a man who happened to be in the building at the time). However, none of the surrounding buildings were touched.