Life on Mercury

Mercurian world is one of extremes. 700 Kelvin on the side exposed to the Sun, yet some areas are never exposed to sunlight and are as cold as deep space. Scientist do not believe there has ever been life on Mercury. The atmosphere of Mercury does show three of the markers required for life as we know it, though.

Scientists base the chance for life on other planets on conditions needed for life on Earth. So, life on Mercury would require, among other things, oxygen in the atmosphere(it does), water(water vapor in the atmosphere and water ice at the poles), and methane as a sign of waste from metabolism(again, it has this in its atmosphere). If the planet’s atmosphere displays all of these things, why do scientists think there has never been life on Mercury? First, the oxygen levels are too low to support life as we know it. Next, the temperature extremes are just too much for life. Third, although there is water vapor in the atmosphere, there is no liquid water, Water ice exists at the bottom of craters and is never exposed to sunlight. Lastly, methane gas. It is in the atmosphere, but is thought to come from geological processes like volcanism or geothermal and hydrothermal activity.

Any ancient life on Mercury would have faced many extinction events. Here on Earth many past life forms have been destroyed by asteroid impacts. The dinosaurs are a classic example. Images of Mercury’s surface returned by the Mariner 10 and MESSENGER spacecraft have shown that the surface has suffered many large impacts. In fact, it was heavily bombarded during the Late Heavy Bombardment that occurred about 3.9 billion years ago. Any one of those impacts could have destroyed any life on the planet. Many scientists believe that a great deal of the planet’s surface was stripped away by one impact. If the impact removed a large portion of the surface, surely it would have taken any life that existed at the time with it.

All evidence that science has do date indicates that there has never been life on Mercury and never will be. The harsh conditions on the planet’s surface and the large amount of carbon dioxide in its atmosphere make it impossible for any life form known to man to exist.

But there are other planets in the Solar System. Here’s an article about life on Pluto, and here’s one about life on Mars.

If you’d like more information on Mercury, check out NASA’s Solar System Exploration Guide, and here’s a link to NASA’s MESSENGER Misson Page.

We have also recorded a whole episode of Astronomy Cast that’s just about planet Mercury. Listen to it here, Episode 49: Mercury.

Vida sobre el mercurio

References:
NASA Solar System Exploration: Mercury
Wikipedia
JAXA: Mercury Quantities
NASA MESSENGER Mission
NASA Multimedia