‘Old Earths’: the search for ancient and habitable (but dying) exoplanets

Illustration depicting the life cycle of Sun-like stars. Billions of years from now, our own Sun will expand into a red giant star, scorching any life that exists. Image Credit: ESO/M. Kornmesser
Illustration depicting the life cycle of Sun-like stars. Billions of years from now, our own Sun will expand into a red giant star, scorching any life that exists. Image Credit: ESO/M. Kornmesser

Researchers at Cornell University are taking a new approach to the search for alien life: looking for habitable planets older than Earth, “old Earth analogues,” which may be nearing the end of their habitable lifetimes. Astronomers would search for biosignatures from worlds much older than Earth, where lifeforms are dying off due to circumstances such as the planet’s star expanding in its old age, gradually heating the planet to a point where life is no longer possible.

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Two Earth-sized exoplanets may exist in closest star system, Hubble observations reveal

Artist’s conception of the Alpha Centauri binary star system and the exoplanet Alpha Centauri Bb. Our own Sun is also shown in the distance. Image Credit: ESO/L. Calçada/N. Risinger
Artist’s conception of the Alpha Centauri binary star system and the exoplanet Alpha Centauri Bb. Our own Sun is also shown in the distance. Image Credit: ESO/L. Calçada/N. Risinger

The closest star system to our own Sun may have two Earth-sized exoplanets orbiting it, a new study has shown based on observations by the Hubble Space Telescope. If confirmed, the discovery would help to illustrate just how common exoplanets are; data from Kepler and other telescopes has also already shown that the vast majority of stars have exoplanets orbiting them, and the number of exoplanets in our galaxy alone is now thought to number in the billions.

Read MoreTwo Earth-sized exoplanets may exist in closest star system, Hubble observations reveal

Scientists create colour-based catalogue of Earthly life forms to help search for alien biology

A hypothetical rendering of colorful plant life on a habitable exoplanet. Although most such alien life, if it exists, found with this technique may be microscopic, it illustrates how analysis of color could help scientists learn more about the physical nature of alien biology. Image Credit: NASA/Caltech/Doug Cummings
A hypothetical rendering of colourful plant life on a habitable exoplanet. Although most such alien life, if it exists, found with this technique may be microscopic, it illustrates how analysis of colour could help scientists learn more about the physical nature of alien biology. Image Credit: NASA/Caltech/Doug Cummings

With exoplanets now being discovered by the thousands, and estimated to be in the billions in our galaxy alone, attention is naturally turning to how astronomers might be able to search for evidence of life on any of those far-away worlds. Now, a team of scientists is taking a novel approach to doing just that, by creating a colourful catalogue of reflection signatures of various life forms on Earth. The new database and research was just published in the March 16 Proceedings of the National Academy of Sciences.

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New technique to study clouds on exoplanets developed by researchers at MIT

Artist’s conception of clouds on Kepler-7b. Image Credit: NASA (edited by Jose-Luis Olivares/MIT)
Artist’s conception of clouds on Kepler-7b. Image Credit: NASA (edited by Jose-Luis Olivares/MIT)

While exoplanets are now being discovered by the thousands, it is still a painstaking process to determine any specific details about them, since they are so incredibly far away. However, astronomers have been devising new techniques to do just that, including one that makes it easier to analyze the property of clouds on some of these distant worlds.

Read MoreNew technique to study clouds on exoplanets developed by researchers at MIT

‘Super-Earth’ exoplanets may be more Earth-like than previously thought

With the number of known exoplanets being discovered now numbering in the thousands (and estimated to be in the billions in our galaxy alone), astronomers have already found an amazingly diverse plethora of worlds. Some of the most common are the “super-Earths,” rocky planets which are larger …

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