Wednesday, February 24, 2016

Earth: A Planet Like No Other

The Known Universe

Multiple Galaxies: This is from a Hubble image that captures a small sampling of the galaxies within the universe. There are, according to current estimates, at least 100 billion galaxies in the universe containing about a billion trillion stars, and substantially more planets. That only one is like Earth is not shocking, but might be disappointing to some people. Nathaniel Scharping for Discover Magazine writesStill, the model is based on what we currently understand about the universe, and if there’s one thing we have figured out so far, it’s that we still don’t know very much. The model creates exoplanets based only on the ones we have discovered, which is an extremely small sample size that probably doesn’t provide a representative cross-section of all of the planets in existence.”
Image Credit: NASA/ESA

An article, by Nathaniel Scharping, in Discover Magazine says Earth is truly unique, so unique that it defies the mathematical odds and expectations of coming into existence. Such is the findings of a model worked up by one astrophysicist, Erik Zackrisson from Uppsala University in Sweden

In “Earth May Be a 1-in-700-Quintillion Kind of Place” (February 22, 2016), Scharping writes:
A new study suggests that there are around 700 quintillion planets in the universe, but only one like Earth. It’s a revelation that’s both beautiful and terrifying at the same time.
Astrophysicist Erik Zackrisson from Uppsala University in Sweden arrived at this staggering figure — a 7 followed by 20 zeros — with the aid of a computer model that simulated the universe’s evolution following the Big Bang. Zackrisson’s model combined information about known exoplanets with our understanding of the early universe and the laws of physics to recreate the past 13.8 billion years.
Zackrisson found that Earth appears to have been dealt a fairly lucky hand. In a galaxy like the Milky Way, for example, most of the planets Zackrisson’s model generated looked very different than Earth — they were larger, older and very unlikely to support life. The study can be found on the preprint server arXiv, and has been submitted to The Astrophysical Journal.
But according to Zackrisson, most planets in the universe shouldn’t look like Earth. His model indicates that Earth’s existence presents a mild statistical anomaly in the multiplicity of planets. Most of the worlds predicted by his model exist in galaxies larger than the Milky Way and orbit stars with different compositions — an important factor in determining a planet’s characteristics. His research indicates that, from a purely statistical standpoint, Earth perhaps shouldn’t exist.
Yet, we do. Which not only shows the limitations of statistics and relying on them for validating a view or even a scientific thesis. Although the model is limited in scope and information, I suspect that astronomers, cosmologists and astrophysicists will not find any planets that match ours, containing all the necessary chemical and biological ingredients to form life as we know it.  It might forever remain in the realm of science fiction.

Perhaps a more important argument to be made is that there might be no other planet remotely like Earth; and our search for other habitable planets that can support us (and our understanding of “life”) might be fruitless. Such a view might make us come to the realization and conclusion that our planet is precious.This is not giving up. This ensures that we protect and preserve our planet for what it offers us. Life.

For more, go to [Discover