Bolide breakup and impact on the surface of Mars (HiRISE/NASA)
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…
The continuing activity at the Chaiten volcano, Chile (NASA)
In May 2008, a dormant volcano in Chile awoke from its 9,000 year sleep. The Chaitén volcano blasted smoke and ash high into the atmosphere, causing the local population to flee from the nearby town, under the ominous clouds of lightning-inducing hot ash and steam. Eight months after the eruption shook the region, the small town in the southwest remains deserted and polluted.
Using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite, a new view above the volcano have become available, showing the destruction in the wake of this regional natural disaster…
The July earthquake in LA caused chaos in the shampoo & conditioner aisles...
Sitting at my desk at 7:42pm (Friday), doing some research on the web (read: procrastinating), I felt something odd. It was as if somebody walked behind my chair, shunting me forward slightly. I turned, and of course no one was there. Slightly confused, I heard my wife shout from the living room, “Did you feel that?” Then I knew I wasn’t dreaming, there had been an earthquake.
That wasn’t my first experience of a quake, back in July 2008, Woodland Hills felt a seismic wave from the magnitude 5.4 earthquake epicentre near Downtown LA. That’s the only way I can describe it, a rolling wave. We were outside at the time, and I was amazed to see the water in the pool slosh over the sides. Now that was my first quake, and I found it pretty exhilarating (as I ran inside to get my video camera to take an eyewitness account of any other tremors, but there were no more to follow).
Today’s was a short and pretty wimpy magnitude 3.4, just a tiny burst of energy. However, interested to find out more, I turned to one of the best breaking news resources out there, Twitter…
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.
For more, check out Phil Plait’s Bad Astronomy article and SpaceWeather.com…
The hot spring, Sapphire Pool at the Biscuit Geyser Basin in Yellowstone National Park (Getty)
Since December 26th, hundreds of small earthquakes have shimmied Yellowstone National Park.
Earthquake swarms are a collection of small earthquakes over a short space of time. These aren’t aftershocks of one primary, larger quake, they are quakes in their own right. Yellowstone National Park, located mainly in the state of Wyoming (stretching into Montana and Idaho), plays host to the Yellowstone Caldera, a volcanic hotspot where molten mantle rock bubbles to the surface. This activity creates hot springs and is the energy source of many geysers.
The last Yellowstone “supereruption” occurred 640,000 years ago, but there have been many smaller eruptions and lava flows since then; the most recent being 70,000 years ago.
Any earthquake in the largest volcanic system in North America will therefore cause excitement and a little concern, and these recent earthquake swarms are an oddity. Yellowstone is no stranger to earthquake swarms, but the recent frequency of events are unusual scientists say.
In an effort to track the swarms, I’ve stumbled across an interesting article where a numerical modelling package has been used to locate and simulate the earthquake swarm breakouts…
The Aztecs, affected atmospheric carbon levels? (Getty)
Global warming anyone? I ask as I don’t want to upset anybody. Forget it, I’m going to talk about it anyway.
Climate change is an important subject worthy of debate. But for a debate to develop into something constructive, all sides need to have some scientific merit. Clearly, if we listen to Leo DiCaprio, Al Gore and the world’s carbon-cutting politicians, we might be led to believe we are damaging the environment… hell, we might even be warming the whole planet through carbon emissions! So, strip the Hollywood glamour and political spin from the debate, does the global warming debate have any science linking human activity with increased global temperatures?
In a new study, focusing on Central and South America, scientists have uncovered possibly one of the earliest recorded cases of human-induced climate change, possibly amplifying (or even triggering) the Little Ice Age in Europe throughout the 16th century and beyond…
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…
Auckland warehouse fire. Meteorite or foul play? (Paul Tonkin)
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.
The meteorite was observed at around 10pm last night, and the fire was eventually extinguished at 11:30pm.
Video of the fireball event over Colorado (Chris Peterson)
Early this morning, a huge explosion lit up the Colorado skies. According to one observatory that videoed the event with its ever-watching all-sky camera, the fireball (or bolide) peak brightness (magnitude -18) exceeded the brightness of a full Moon 100 times. An awesome event. The Cloudbait Observatory, near Denver, is calling on eye-witnesses to submit their reports so possible meteorite fragments can be found on the ground. Only last month, a similar effort resulted in Canadian meteorite hunters finding over two dozen fragments from the Saskatchewan fireball.
For all the information about the Colorado event, check out my Universe Today article Exploding Colorado Fireball, 100 Times Brighter than the Moon (Video).
I must admit though (as one of my readers pointed out), it is surprising to hear about this recent flurry of large fireball events. Some of these meteoroids are as big as 10 tonnes (in the case of the Saskatchewan fireball), and scattered meteorites are being found on the ground (fortunately over sparsely populated regions). Are these recent series of fireball spottings down to improved observation techniques and a bit of luck? After all, the October fireball was observed directly over several all-sky cameras dedicated to spotting meteors; the November fireball was seen by a huge number of people in cities across the Saskatchewan/Alberta border and last night’s fireball appeared above another dedicated meteor all-sky camera.
A few of these events are expected every year, so this is certainly nothing to be concerned about, we’re just getting better at observing these transient events…
University of Calgary graduate student Ellen Milley poses with a fragment of a meteorite in a small pond near Lloydminster, Sask. (AP)
Although I am still in Las Vegas enjoying the Thanksgiving aftermath, I wanted to give an update of the Canadian fireball that dramatically exploded over the Saskatchewan skies last week.
Having read though some of the updates across the space blogosphere, I thought it would be good to give the event a brief run-down via the pile of space blogs that have been following this surprise explosion and resulting discovery of meteorite fragments near Lloydminster, Saskatchewan…
In a renewed attempt to bring the concern about a potential asteroid strike to the world’s attention, former Apollo 9 astronaut Rusty Schweickart briefed UN officials on Tuesday about a report entitled “Asteroid Threats: A Call for Global Response.” The report has been drawn up by the International Panel on Asteroid Threat Mitigation (IPATM), formed by space explorers and scientists in an effort to put a contingency plan into action to limit the devastation caused by a theoretical impact.
The key point here is that the IPATM is not predicting an immediate catastrophic asteroid collision, it merely wants the UN to recognise there is a danger out there and to enact procedures to save lives and possibly remove the threat all together…