Posted on August 6, 2017
Did you know that researchers have found more meteorites on Antarctica than on any other continent? There are several reasons - Antarctic is a dry desert, so iron-rich meteorites don't corrode nearly as quickly, the contrast between white snow/ice and dark meteorites is stark, Antarctica has no trees or bushes or grass to hide meteorites.
 |
| In some areas of Antarctica, there are lots of meteorites. This is because ice flows that move veeeeerrrrrrrryyyy slowly to the sea sometimes get "stuck" on land features below the ice. In those places, sometimes wind blows away the top layer of snow, exposing older layers of ice. |
One of the meteorites found in Antarctica, named Allan Hills 84001, is thought to have come from the planet Mars. (Many meteorites are made of rocks that formed on Mars, but were chipped off - and ejected from the planet's surface - from the impact of other meteorites!)
This particular meteorite does not quite fit into any of the categories of Martian meteorites. When researchers were studying it, some thought that they found evidence for microscopic fossils.
When you hear the word "fossils," do you immediately think of huge dinosaur bones, hand-sized shark teeth, or saber tooth cat skulls with foot-long saber teeth? Of course, most fossils are less fabulous, and many are very small. Microfossils are so small that they can only be seen with a microscope.
The scientists who were excited about ALH84001 had studied it with a scanning electron microscope. Some of the structures they saw resembled bacteria but were smaller than any known cellular life.
 |
| The chainlike structure in the middle of the photo puzzled scientists...but look a bit like incredibly tiny bacteria. |
On this date in 1995, a NASA scientist announced the possibility that fossil traces of extra-terrestrial life had been discovered in a magazine article. Note that he only announced the POSSIBILITY - not a certainty!
Since then, loads of people became suddenly (and, mostly, briefly) interested in exobiology (the study of the likelihood and possible nature of life forms from other planets or in space). Then-President Bill Clinton even gave a speech about the find. But a lot of scientists were skeptical of the ET-life claim.
Since then, some scientists have formed similar structures in a lab without any bacteria (or any other life form). So it is even more unlikely, at this point, that ALH84001 is evidence for extra-terrestrial life.
The search goes on...
Also on this date:
Plan ahead:
Check out my Pinterest boards for:
And here are my Pinterest boards for:
No comments:
Post a Comment