This is how we go about finding extraterrestrial life.
I think this whole process is quite fascinating. If you used a scientific instrument known as a spectroscope and examined the light coming from the sun, you could tell the elements present in the sun. This was first discovered way back in 1802. It has modern applications that might discover the likelihood of extraterrestrial life in the near future.
The process works like this: When a planet orbits around a sun, such as ours, and the planet comes between us and the sun, termed a transit, the sunlight is partly blocked by the planet, but some light from the sun passes through some atmospheric gases around the planet, if it has an atmosphere and the spectrum of that light shows a difference from just the one of the sunlight. That difference comes from the gases in the planets atmosphere.
We can apply the same basic procedure with exoplanets (planets that orbit other stars) when they transit (move in front of) their sun.
We check the spectrum of the stars light beforehand and then check to see what gases are present in the atmosphere of the extrasolar planet.
There are some specific gases that if present in very odd quantities tend to be present only when life exists on the planet such as oxygen, ozone, and methane (see the article in New Scientist October 9, 2013.
Certain ratios and concentrations tend to increase that probability, especially if the gases are reactive and naturally deplete. Their continuous presence indicates replenishment.
Until such a time as we can physically explore some of the moons around Saturn, or more advanced probes further explore Mars or we eventually travel the light years of distance to other worlds, this or some similar system will be how we detect the possibility of life on distant worlds.
The presence of these or other potential gases possibly present in other different types of atmospheres could perhaps be tested using the James Webb Space Telescope due for launch in October 2018. (see jwst.nasa.gov)
Until such a time as when we can travel great distances or send probes, this appears for now to be our best option.
The next few years may be very exciting indeed.
Share your thoughts on life elsewhere? Do you believe it exists?
or check out our most recent articles: