The Science of Comets (and Asteroids)

The last part of 2014 has been a great time for space exploration, with the remarkable achievement of landing a robot on a comet that is over 6 billion kilometres (thats 320 million miles) away from Earth.

Rosetta_-_comet_fly-by

 

Many people had never heard of the Rosetta space mission before now, and if they had before, they’d probably forgotten about it until it came up in the news a couple of weeks ago. The most common question that was asked though was this: “why are we landing a probe on a dead rock floating through space?”

Well, they may look like random pieces of floating rock, but there’s a lot more to comets (and asteroids) than first meets the eye.

Comets: Icy pieces of rock that are remnants of the formation of our solar system – as they travel through space and get closer to the Sun, they heat up and emit gases, often leaving behind a visible trail (the most well known is Halley’s Comet, which is visible from Earth every 75 years). 

Lspn_comet_halley
Halley’s Comet

 

Asteroids: Large pieces of rock that are sometimes called planetoids due to their size and gravitational pull. The majority of the asteroids in the solar system are found in the asteroid belt between Mars and Jupiter. The asteroids in this belt are thought to be either pieces of rock that never formed into a planet due to the pull of Jupiter or the remnants of a planetary collision. Occasionally, an asteroid falls away from the belt and travels though space (it was an asteroid from the belt that wiped out the dinosaurs). 

Asteroid_Belt
The asteroid belt in our solar system

 

Now that we know the difference between the two, let’s get down to the reasons why they are so interesting. As I mentioned above, comets and asteroids date back to the formation of our solar system, or are the remnants of past planets. Because of this, they are a window into the past, giving us information about events that happened millions of years ago. By studying asteroids and comets, we can learn about physics, planet formation, geology and so much more.

The most interesting part though, is that comets may hold the precursors to life itself. That’s right, these floating chunks of ice and rock may be the reason why you and I are here today. By containing various organic compounds (chemical compounds containing carbon), comets hold the building blocks of nucleic acids and amino acids, which are integral parts of life. Alongside this, it’s thought that comets are also responsible for the amount of water that Earth has.

Therefore, with the right mix of organic compounds and water, you have the possibility for life to emerge and evolve. This is what the Rosetta spacecraft is looking for, all those miles away. It’s going to be sampling the rocks for traces of nucleic acids and these other compounds in order to solve the eternal question of ‘why are we here?’.

star-stuff

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