Hymalaia is an instrument resembling an icebox with the help of which scientists have been able to determine the exact texture of a comet. And these findings, published in the Journal of Physical Chemistry, are pretty reassuring.
The lead author of the study is Antti Lignell, who is a postdoctoral scholar at the California Institute of Technology in Pasadena.
“A comet is like deep fried ice cream,”
according to Murthy Gudipati of NASA’s Jet Propulsion Laboratory in Pasadena, California, who is a corresponding author the recent study.
“The crust is made of crystalline ice, while the interior is colder and more porous. The organics are like a final layer of chocolate on top.”
What happens is that as a comet is getting closer to the Sun, its surface, otherwise rather soft, crystallises and hardens. Thus water-ice crystals form, which become denser and more ordered, while other molecules containing carbon are expelled towards the surface of the comet, resulting in a crunchy comet crust that’s “seasoned” with organic dust.
This is not the first time scientists have announced that comets have hard surfaces and soft interiors. This theory was also confirmed as Rosetta’s Philae landed on the surface of 67P/Churyumov-Gerasimenko last year. Not to mention the Deep Impact mission that looked into the same issues among other things.
Lignell and Gudipati put together a closely resembling model of crystallising comet crust and began their experiments with amorphous (porous) ice, which is by excellence the proposed composition of some of the chilliest comets and icy moons.
The icy comet surfaces are different from the ice we have here on Earth because of the fact that we don’t have temperatures that are so low so as to form amorphous ice on the planet. So the scientists involved in this discovery used the Himalaya instrument in order to slowly warm up amorphous ice mixtures from minus 243 to minus 123 degrees Celsius, thus imitating the conditions a comet would have to go through throughout its journeys towards the Sun.
Both scientists regard comets as time capsules that contain within themselves clues to our planet’s history and to the birth of our solar system.