Sometimes, when talking about space, it is difficult to put into words how truly amazing and mind-bendingly awesome something is. This image definitely fits into that category.
What you are seeing here is the gaps in the disk around a star created by actual planets forming. It’s truly stunning. Often, it can be hard to fathom objects in space, such as large galaxies or nebulae. Here, though, we can see a planetary system not too dissimilar to our own taking shape.
At the center of this image is the star TW Hydrae, a similar star to our Sun located about 175 light-years from Earth. It is just 10 million years old, so it hasn’t yet formed a fully-fledged solar system like ours. Instead, we are seeing the process of planet formation, and thanks to the star being face-on in relation to us, we get a great view of the process in action as protoplanets sweep out gaps in the surrounding dust and gas.
The image, presented in a paper published in the Astrophysical Journal Letters, was taken by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. Thanks to the sensitivity of ALMA, intricate details of the system can be seen.
Very close to the star, visible not in the main image but in a zoomed-in segment, there appears to be a planet forming in an Earth-like orbit, located about 1 AU from the star (1 AU, astronomical unit, is the distance from Earth to the Sun in our Solar System), about 150 million kilometers (93 million miles).
Here we can see the zoomed-in segment that may indicate a planet forming in an Earth-like orbit. S. Andrews (Harvard-Smithsonian CfA), ALMA (ESO/NAOJ/NRAO)
Elsewhere in the main image, you’ll see two further gaps in the ring of dust and gas surrounding the star. These are located at distances comparable to Uranus and Pluto in our Solar System, about 3 and 6 billion kilometers (1.9 and 3.7 billion miles) respectively.
"The new ALMA images show the disk in unprecedented detail, revealing a series of concentric dusty bright rings and dark gaps, including intriguing features that suggest a planet with an Earth-like orbit is forming there," said Sean Andrews from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and lead author of the paper, in a statement.
How planets actually form is still up for debate. Leading ideas at the moment point towards a “pebble theory,” where bodies gradually accumulate smaller debris over time, growing larger and larger until they eventually form planets. They sweep up material in their orbits, forming gaps in the protoplanetary disk around their star, as seen in this image.
TW Hydrae is the closest known protoplanetary disk to Earth, and together with other images like that of HL Tau, we are starting to piece together the timeline of how planets take shape. For now, bask in the glory of this stunning image. Who knows, in a few hundred million years it might even give rise to a planet just like our own.
