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A Habitable Planet May Be Just Around The Corner

By David Reneke

Astronomers have discovered the closest habitable planet outside our solar system, and discovered one of the biggest black holes ever.

Astronomers from the University of NSW have discovered the closest potentially habitable planet found outside our solar system so far, orbiting a star just 14 light years away. The planet, more than four times the mass of the Earth, is one of three that the team detected around a red dwarf star called Wolf 1061.

“It is a particularly exciting find because all three planets are of low enough mass to be potentially rocky and have a solid surface. The middle planet, Wolf 1061c, sits within the ‘Goldilocks’ zone where it might be possible for liquid water, and maybe even life, to exist,” says lead study author Dr Duncan Wright.

For us humble human beings it’s fascinating to look out at the vastness of space and think that a star so very close to us, a near neighbour, could host a habitable planet. While a few other planets have been found that orbit stars closer to us than Wolf 1061, those planets aren’t considered remotely habitable.

The three newly detected planets orbit the small, relatively cool and stable star about every 5, 18 and 67 days. Their masses are at least 1.4, 4.3 and 5.2 times that of Earth, respectively. The larger outer planet falls just outside the outer boundary of the habitable zone and is also likely to be rocky, while the smaller inner planet is too close to the star to be habitable.

Using state-of-the-art spectroscopy, the UNSW team developed techniques that allowed them to study more than a decade’s worth of observations of Wolf 1061. These three planets right next door to us join the small but growing ranks of potentially habitable rocky worlds orbiting nearby stars cooler than our Sun.

Small rocky planets like our own are now known to be abundant in our galaxy. Multi-planet systems also appear to be common, but most of the rocky exoplanets discovered so far are hundreds or thousands of light years away.

The close proximity of the planets around Wolf 1061 means there is a good chance they may pass across the face of the star. If they do, it may soon be possible to study the atmospheres of these planets to see whether they would be conducive to life.


Strange Things Happening to this Supermassive Black Hole

Astronomers have spotted one of the biggest black holes ever discovered. What’s even more surprising is its location and the strange reason it got so big.

The recently discovered supermassive black hole tips the scales at more than 17 billion times the size of the Sun, making it one of the biggest ever discovered. Generally, black holes this big can be found at the centre of a massive galaxy cluster but this supermassive black hole was discovered in a moderate sized elliptical galaxy, with only a few surrounding galaxies nearby. It’s kind of like finding a single towering skyscraper in a remote small town.

Most monster black holes discovered to date tend to be found in dense clusters of galaxies. Researchers may have to rethink their ideas about where gigantic black holes reside, and how many of them might populate the universe.

This supermassive black hole is essentially two black holes that united long ago when two random galaxies bumped into each other. Ultimately, the boundaries of the two black holes were distorted so much by each other that they combined into one extremely large supermassive black hole.

The black hole is much bigger than astronomers expected for the size of the galaxy or where this galaxy lives. Suspecting they had spotted a very large black hole, team members started examining the elliptical galaxy in more detail and began probing the black hole’s “sphere of influence” using the northern half of the Gemini twin telescopes in Hawaii and Chile.

They also scoped out the site with data from NASA’s Hubble Space Telescope. The stars were going so fast that the only way they could be travelling at this speed is if there was a 17 billion solar mass black hole at the centre.

Astronomers agree we’re going to find more black holes like these. The next question is: how massive can these black holes be? Is 17 billion solar masses where they stop growing, or could there be even bigger monsters out there we haven’t found?


David Reneke is an astronomy lecturer and teacher, a feature writer for major Australian newspapers and magazines, and a science correspondent for ABC and commercial radio. Subscribe to David’s free Astro-Space newsletter at www.davidreneke.com