As I perused through current events happening in the astronomical world, I was drawn to a new report detailing the features on the surface of Mars suggesting the existence of large rivers.  It was at this moment that it occurred to me that I have yet to write about the eight planets in our solar system (I wrote about Pluto, but Pluto had its planetary membership revoked a few years back).  With that, I thought it best I start with Mercury, the closest planet to the Sun.

It’s Mercury!

Mercury is the smallest planet in our solar system; having a diameter of roughly 3000 miles, it only slightly larger than Earth’s moon which has a diameter of approximately 2200 miles.  Mercury, however, is also the “fastest” planet in the solar system because it has the takes the shortest amount of time to revolve around the Sun – about 88 Earth days.  However, having the title of the fastest planet is not without its downsides.  Since Mercury is so close to the Sun, the Sun’s solar flares and radiation have almost completely stripped Mercury of its atmosphere.  This makes it incredibly difficult for Mercury to regulate its surface temperature.  During the day Mercury’s surface can reach temperatures of over 800 degrees Fahrenheit.  Likewise, at night, the surface of Mercury plummets to a chilling -300 degrees Fahrenheit.  These extreme temperatures go to show how much Earth’s atmosphere does for our temperature regulation!

The Roman God Mercury

Mercury was named after the Roman god of speed, messages, trickery, commerce, and eloquence.  Personally, I feel there are a few contradictory terms in the description of Mercury.  In any case, Mercury was named after the Romans, who were able to observe the five “classical planet” (Mercury, Venus, Jupiter, Saturn, and Mars).  The Romans named each of these observable planets for their Roman gods.  While it is not 100% clear, Mercury’s name was most likely given because of its fast orbit period.

At the moment, there have been two major scientific explorations of Mercury.  Way back in the 1970’s, NASA launched the Mariner 10 to take images of the planet and relay them back to Earth over the course of a two-year mission.  The second mission was Messenger, launched in 2008 by NASA.  Messenger was strategically launched into the orbit of Mars so that it could have more time circling and recording the planet.  This strategy worked well for the next 7 years before Messenger finally collided with the surface of Mercury.

Unfortunately, Mercury doesn’t interest me very much.  I think it’s incredibly interesting that the temperatures spike so drastically because Mercury lacks an atmosphere, but I feel there simply isn’t much history to the planet.  When doing some research, I was hoping to find a bit into the story of how the Romans decided to name the planet Mercury, but it appears they did so relatively arbitrarily.  Regardless!  Mercury is a planet, and it must be respected as such.

The Transiting Exoplanet Survey Satellite (TESS)

Midway through last year, NASA launched a new object into space called the The Transiting Exoplanet Survey Satellite (TESS).  The purpose of this machine is to fly throughout space and find new planets nearby the Sun.  With this is mind, one huge question would be if there is life on those other planets  If there isn’t life on those planets, could the planet still harbor life in the future?

After looking into the different requirements for establishing life on other planets, I stumbled upon a brief list of criteria that a planet should satisfy in order to culture life.

Temperature:  Temperature is a very important qualifier for life developing on other planets.  Naturally, if a planet is too cold, very few – if any – organisms would be able to survive.  One of the main reasons for this is that water would be unable to exist in a liquid state.  Temperature, however, also plays a role in the development of life.  With lower temperatures, molecules move much slower which causes reactions to happen less frequently.  These important chemical reactions are important in the development of life, so if they happen slower, it might take much longer for there to be potential for life.  Likewise, if the temperature is too hot, it will cause molecules to break down before they are able to form something that resembles life.

Water: Water is also an extremely important necessity for life.  Since water allows the transportation of chemicals and other resources throughout cells, it is important for the water to be liquid.  This, in turn, relies on the temperature being correct.

Atmosphere: The atmosphere of a planet can immediately determine whether a planet can contain life.  If the planet simply doesn’t have an atmosphere, it makes the planet vulnerable to external elements such as solar flares and asteroids.  If there is too much of an atmosphere, it might capture too much heat and make the surface of the planet uninhabitable.  An example of this would be Venus.  Its atmosphere is so thick that the surface of the planet is incredibly warm.

Energy: This category refers heavily on sunlight or light from the parent star.  If there is too little light, organisms have a high chance of not getting the chemicals they need from sunlight to survive.  Naturally, if there is too much energy directed towards the planet there are also issues.  Too much energy towards a planet could mean the planet gets too hot depending on how thick the atmosphere is, or the energy could prove harmful towards the organisms.

Since planets must nearly pass all of these criteria, it’s no mystery why so many of them cannot or do not contain life.  However, all of these criteria are based on the assumption that our human-defined definition of life is applicable to all organisms throughout the universe.  For all we know, there isn’t one set of rules for a living thing.  There could be countless variations of life that we simply aren’t aware of.