A renewed dream of life beyond Earth

The discovery of seven Earth-sized – maybe even Earth-like – exoplanets sparks fresh debate about whether we are alone in the universe

PUBLISHED : Wednesday, 01 March, 2017, 3:49am
UPDATED : Wednesday, 01 March, 2017, 3:49am

Astronomers have discovered not one, not two but a whopping seven Earth-sized planets orbiting around a single star. And they are just 40 light years away from us. What’s more, some of them may be “temperate” enough to hold liquid water, signifying the possibility of life.

Of course, we shouldn’t sensationalise, and the findings need to be put into context. The three inner planets are likely to be too hot, and the outer planet is probably too cold. However, the three in the middle might be just right to harbour liquid water even on the surface, given sufficient atmospheric pressure.

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It’s not the first time scientists have discovered so many exoplanets. Of the 3,449 planets identified so far from star systems beyond our own, some of them may harbour the biochemical essentials of life. There are probably many more like them out there.

With the latest news, we have, of course, not discovered a cousin of Earth, let alone seven of them. Nor have astronomers discovered life on any of them. What the Dutch-led multinational team has found is a planetary system with a star called Trappist-1 – also known as an ultra-cool dwarf star – that is not as hot or massive as our sun. This enables the researchers to turn their telescopes to study the planets in great detail without being dazzled as they would be if they were looking at much brighter and more massive stars. This is because those planets block much more light when they pass between their dwarf star and our Earth than would be the case with a more massive and much brighter star like our sun.

It also allows the research team to develop the notion of a temperate or inhabitable zone beyond the narrow understanding we have from our own Earth and the solar system.

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Whatever turns out to be the case, the discoveries of these wondrous new worlds are marking new frontiers for astronomers and biologists. Earth just marks an infinitesimal corner of the universe, which may be teeming with life.

There are new things under the sun. Indeed, there may be an infinite number of stars with their systems hiding wonders we cannot even dream of.