Meteor Shower… On Mars!
Written by Tammy Plotner
What's that? Another meteor shower we can't possibly see? Of course you can. All you need to view this meteor shower is a backyard on Mars! A team of scientists led by Armagh Observatory have, for the first time, detected a storm of shooting stars on Red Planet.
What happens when the orbit of Mars intersects with debris from comet 79P/du Toit-Hartley? Scientists were hard at work making predictions. The detections were then cross-referenced with observations of activity in the Martian ionosphere by NASA's Mars Global Surveyor (MGS) satellite. Says Dr. Apostolos Christou:
"Just as we can predict meteor outbursts at Earth, such as the Leonids, we can also predict when meteor showers are going to occur at Mars and Venus. We believe that shooting stars should appear at Venus and Mars with a similar brightness to those we see at Earth. However, as we are not in a position to watch them in the Martian sky directly, we have to sift through satellite data to look for evidence of particles burning up in the upper atmosphere."
We're all familiar with the cause of most meteor showers. They happen when a planet (and not always ours!) passes through the debris trail left by a comet as it moves along its orbital path. The material lets us glimpse into the age, size and composition of particles ejected from the comet's nucleus, the speed at which it was thrown off, as well as general information about the structure and history of the comet itself. Oh, to be a comet watcher on Mars! About four times as many comets approach the orbit of Mars than the Earth's and the greatest majority of these are Jupiter Family Comets.
Studying Martian meteor showers can definitely improve our understanding of meteor showers and the Jupiter Family Comets as well. JFC are short period comets with an orbital period of less than 20 years. Their orbits are controlled by Jupiter and many are believed to originate from the Edgeworth-Kuiper Belt, a vast population of small icy bodies that orbit just beyond Neptune. Famous JFCs include Comet 81P/Wild 2, which was encountered by the Stardust spacecraft in January 2004 and Comet Shoemaker-Levy 9, which broke up and collided with Jupiter in July 1994.
When meteor particles burn up in a planet's atmosphere, metals contained within them are ionised to form a layer of plasma. On Earth, this layer has an altitude of approximately 95-100 kilometres and on Mars the layer is predicted to be around 80-95 kilometres above the Martian surface. Meteor showers leave a narrow layer of plasma superimposed on top of the main plasma layer, caused by meteors that are general debris from the Solar System. Dr. Christou and his colleagues developed a model to predict meteor showers caused by the intersection of Mars with dust trails from comet 79P/du Toit-Hartley. From the model, the team identified six predicted meteor showers since the MGS satellite entered into orbit around Mars in 1997. Although the metallic ions cannot be observed directly by MGS instruments, evidence for the plasma layer can be inferred by monitoring electron density in the Martian atmosphere using the spacecraft's radio communication system.
Just like earthly meteor showers, we can predict all we want - but sometimes we draw a blank. In this instance only one of the six predictions came true. In the April 2003 data, the team found that an ionospheric disturbance appeared at the exact time of the predicted meteor outburst. The height of the disturbance corresponded with the predicted altitude for the formation of the metallic ion layer and its width and multi-peaked shape were similar to structures observed in the Earth's ionosphere linked to the Perseid meteor shower.
For the 2005 data, no features were observed near or immediately after the predicted meteor shower. Dr Christou says, "We speculate that we don't see anything in the 2005 data because the meteors burned up deeper in the atmosphere where their ionisation is less efficient. If we are going to get a clear picture of what is going on, we need more optical and ionospheric observations of meteor showers at both the Earth and Mars so we can establish a definitive link between cause and effect. Equally importantly, we need further observations of Martian meteor showers, either from orbit or from the planet's surface, to confirm our predictions. Finally, we need to improve our prediction model by tracking more comets that might cause meteor showers on Mars."
Dr Christou is now investigating the possibilities of making observations with Europe's ExoMars mission, which is due to land on Mars in 2015.
Filed under: Mars, Planet News
April 2nd, 2008 at 8:22 am
Is this real or a late April Fool's joke? That image looks horrendously altered.
April 2nd, 2008 at 10:09 am
If you hover over the image, it says it's computer-generated. It's likely an artistic impression of something you might expect to see from the Martian surface from the height of one of the Rovers.
April 2nd, 2008 at 1:55 pm
The information contained in the article suggests (indirectly) that the image is a simulated event.
April 2nd, 2008 at 8:08 pm
Why not just wait until a REAL photo captures a meteorite?
Why manufacture a photo of something that no one refutes actually takes place. It's just that the rovers werent designed to capture such photos effectively.
I don't apprecite having to 'keep-a-lookout' for manufactured information within articles.
April 3rd, 2008 at 1:58 am
I kind of agree with Triskelion - no-one to my knowledge has disputed that these thing occur, so digitally altered, artisic impressions (ham-fisted or not) don't help. It's not as if we're dealing with an interstellar event or other pheomenon that may stretch our imagination is it?
April 3rd, 2008 at 5:18 am
I agree my attempt to depict a meteor falling through the martian atmosphere was lame. Can I at least get a D+ for trying to capture your attention? (she blushes)
Since I am able to alter my posts, I've switched it out for one that shows where the locations are on Mars that have detected meteoric activity. It's the real, scientific deal - but it's also not as easy to understand in small format.
As a radio meteor scatter enthusiast, I was pretty excited with the news that MGS has picked up the signal. I can dig the graphs, but others might not. Same goes with the topographical map. I was simply afraid that it wouldn't reach right out and grab your attention because it doesn't clearly depict what's going on.
Anyhow… I appreciate your responses! I also offer my apologies for severly underestimating the reader's need to check out the factual illustration. I will consider it a lesson well learned and promise not to insult your collective intelligence again with another lame attempt a creating an illustration.
Humbly yours….
April 3rd, 2008 at 8:24 pm
Thank you! I appreciate your responiveness! I could not help but notice that the shape of the ice cap is a bit familar, also just like Anarctrica!. Make you wonder if there is a common process that leads to that basic topography.
April 4th, 2008 at 4:35 am
hmmmm … maybe Slartibartfast ( http://en.wikipedia.org/wiki/Slartibartfast ) couldn't be bothered designing a new coastline/whatever for the South pole on a next door planet?
I am sure someone will eventually come up with some mathmatical formula for the shape of polar ice caps, possibly involving fractal geometry or something …
(and maybe a few glasses of "a nice red" - LOL)
April 24th, 2008 at 11:56 am
the republic will not stand for this