Life: Is It Only Restricted to the Pale Blue Dot?

For the average person, talks about quarks, neutrinos, or exobiology can be hard to fathom. Some scientists have dedicated their time and conducted experiments that might somehow give us an inkling that there might be other planets that humans can inhabit aside from where we are now: a pale blue dot in the edges of the Milky Way galaxy. Despite their efforts and investments, it is apparent that there’s still a long way to go for humanity. We are still perhaps in the infancy of space exploration.

“Shouldn’t we be content to be cosmic sloths, enjoying the universe from the comfort of Earth? The answer is, no,” Stephen Hawking, a famous theoretical physicist, author of A Brief History of Time, and one of the authors of black hole laws, answered in an interview: “The Earth is under threat from so many areas that it is difficult for me to be positive.” In a BBC interview, the scientist laments regarding the state of our planet: “We are close to the tipping point, where global warming becomes irreversible. Trump’s action could push the Earth over the brink, to become like Venus, with a temperature of 250 degrees [Celsius], and raining sulfuric acid.” referring to Trump’s decision to pull the US from the Paris climate deal. In a lecture last 2016, he added: “Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or 10 thousand years.” At the present moment, there are no other worlds proven to be habitable.

A Brief intro on galaxies

A galaxy is best defined as a collection of stars, remnants of dead stars, interstellar dust, gas, and dark matter. Its origin roots from the Greek word galaxias, which translates as “milky”, hence, our present universe’s namesake.

What are the types of Galaxies?

Galaxies are often categorized by Astronomers into three: spiral, elliptical, and irregular. Their sizes range from dwarf galaxies to giant galaxies. They differ in the number of stars, where dwarf galaxies contain as little as 100 million stars, while giant galaxies contain more than a trillion stars.

Elliptical galaxies can be circular or elongated. Compared to the other galaxies, ellipticals contain less gas and dust; older stars dominate these galaxies and are not producing more.

Spiral galaxies are disk-like and flat in shape. Their stars are usually found on yellowish bulges in their centers. These galaxies mass produce stars and comprise the majority of galaxies in the universe.

Irregular galaxies have no definite shape and contain very little interstellar dust. These galaxies are few in the present and are more abundant in the early stages of the universe.

Life Beyond Earth

Supporting life requires a vast amount of conditions and restrictions: liquid water, oxygen, and orbit. If we are to be located in the center of the Milky Way, the stars can explode anytime, which can disrupt our planet’s ozone layer and release deadly ultraviolet rays.

“We’re the first to look at how the history of galaxies affects their habitability,” states physicist Duncan Forgan, who is studying regions far from a galaxy’s center. From their simulation, the team postulated that there is a probability that an Earth-like planet might form on these recesses of the galaxy. There is also a chance that inhospitable ones, like Mercury, may be formed.

Due to the constant explosion of large planets, adjacent planets might be affected. The simulation shows that most habitable planets can survive if they are situated in areas far from the dense collection of stars where most supernovae explosions occur. For the Milky Way and the other spirals, being in the eye can lead the planet to a faster extinction. The diffuse arms, on the other hand, can nurture hospitable planets.

The team’s research does not just focus solely on the stars, but also covers the scope of the galaxy, extending to the objects beyond the spiral arms where they postulated the presence of “pockets of hospitality.”

Photo Sources:

Cover Photo – Twitter
Photo 1 – Pixabay
Photo 2 – NASA
Photo 3 – NASA
Photo 4 – NASA
Photo 5 – NASA