Astronomers Find a Comet-Like Planet in Seemingly Impossible Orbit

Monday, 18 December 2017 - 7:26PM
Space
Astronomy
Monday, 18 December 2017 - 7:26PM
Astronomers Find a Comet-Like Planet in Seemingly Impossible Orbit
NASA/JPL-Caltech
Astronomers have made an incredibly significant discovery in the form of a so-called "hairy planet" orbiting around a red dwarf star, and which answers questions that scientists have been pondering for over ten years.

One of the star GJ436's planets is very special for a number of reasons: the planet GJ436b is referred to as being "hairy" because, much like a comet, it has a trail of ice and vapor that follows it on its rapid journey around its star, making it look like thick strands of hair are swooshing along in its wake. This isn't the most interesting part, though.

What makes GJ436's planet special is its bizarre orbit - instead of circling around its star in a circle around its equator, like most planets, this hunk of hairy rock zips around in a tight ellipse, running perpendicular to an average planet's orbit and moving extremely close to the red dwarf star at certain points. The research was just published in Nature Communications.



To help illustrate this: when we look at the map of the Earth, we're looking at a 2D simulation of a three-dimensional object (no matter what conspiracy theorists might claim). The plane of our solar system, on the other hand, is actually as flat as it appears in the maps. The sun spins, and the planets all orbit around the sun's equator, generally in relatively (but not always entirely uniform) circular orbits.

This is the case for most planets as they orbit around stars, but GJ436's major planet is different. The planet traces a very long, skinny orbit that extends long beyond the star's poles, traveling up and down on its own unique axis, rather than round and round. Similar behaviors are sometimes seen with smaller objects, but GJ436b is roughly the size of Neptune.

The fun part of this for scientists is how the strange orbit indicates that something big (and thus far unidentified) is skewing the hairy planet's orbit, forcing it round and round in such a strange shape that it seems to defy the standard rules of planetary gravity. According to Hervé Beust, one of the scientists who created the calculations for the planet's orbit:

Opening quote
"Our calculations indicate that not only would the planet not move along a circle around the star, as we've known for 10 years, but it should also be on a highly inclined orbit. That's exactly what we just measured." 
Closing quote


This is a big deal for astronomers, as it poses something really exciting: an anomaly.

Our understanding of the universe is limited to what we can see and observe, so whenever we find a planet that appears to behave in an unusual manner that doesn't fit our existing rulebook, it gives us an opportunity to learn something, and examine or challenge existing theories.

There's been a lot of speculation over the years about how large planets or other bodies could affect planetary alignment - one new theory even claims that the planet Mars was forced out of its original orbit thanks to the size and weight of the nearby Jupiter. GJ436b may finally hold the proof of this phenomenon in action that scientists have been looking for.

For now, the biggest question is what could possibly be skewing the hairy planet's orbit, and why we haven't managed to spot it yet. Whatever the solution to this conundrum, it's certain to be absolutely fascinating.
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