A long time ago, astronomer Dan Coe discovered a galaxy far, far away… so far, it was considered to be perhaps the most distant in the universe.
Little did he know that what he saw with the Hubble Space Telescope then, MACS0647-JD, might actually be two galaxies instead of one.
Cue a cymbal crash and a John Williams musical score. Crawl, crawl, crawl…
The revelation that Coe’s space object might actually be two galaxies merging together is yet another new finding in the James Webb Space Telescope saga, Hubble’s infrared successor. In a new blog post from NASA, the European Space Agency, and the Space Telescope Science Institute, Coe describes the difference the new observatory has made: What appeared as a pale red dot 10 years ago — a tiny galaxy a fraction of the size of the Milky Way in the first 400 million years after the big bang — has a little blue companion. Now scientists are discussing what it means.
« If this is the most distant merger, I will be really ecstatic! » said Tiger Yu-Yang Hsiao, an astronomer at Johns Hopkins University, in the NASA blog.
« If this is the most distant merger, I will be really ecstatic! »
The purpose of the $10 billion Webb telescope is to help scientists understand how the first stars and galaxies formed in the universe, estimated to be 13.8 billion years old. In astronomy, looking farther translates into observing the past because light and other forms of radiation must travel incredible distances to reach us. Light gets stretched into the infrared, which human eyes can’t see but Webb’s highly sensitive mirrors can detect. Scientists then translate the data into colors.
A phenomenon known as gravitational lensing helped Webb reveal more information about MACS0647-JD. The massive gravity of a cluster of galaxies in the foreground acted as a cosmic lens, bending and magnifying light from the distant system. Not only did this effect make MACS0647-JD more visible, but it scattered copies of the system at different scales in three parts of the image, according to NASA.
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Prior to Webb, scientists only knew of a handful of galaxies in the early period of the universe, said Rebecca Larson, an astronomer at the University of Texas in Austin who is part of the research team.
But « Studying them can help us understand how they evolved into the ones like the galaxy we live in today, » she said in the blog.
Researchers said the blue gas in the image indicates very young star formation and little dust, while the red is dustier and older. Scientists plan to probe deeper to determine whether these are two galaxies or two clumps of stars within one galaxy.
« This is not a long exposure, » Larson said. « We haven’t even really tried to use this telescope to look at one spot for a long time. »
