“No one was expecting anything like this.” So says Michael Boylan-Kolchin of the University of Texas, Austin in a recent issue of Science. As I would tell my astronomy students, this is when things begin to get interesting.
The James Webb Space Telescope (JWST) has the ability to see into an era of universal history heretofore invisible to us. The oldest image we have from other missions, from when the universe was merely 370,000 years old, is of the cosmic microwave background. This “baby picture” shows ripples and clumps that scientists believe eventually formed clusters of galaxies containing the first stars.
https://upload.wikimedia.org/wikipedia/commons/0/0b/Planck_satellite_cmb.jpg
The Hubble Space Telescope peered far out into the universe and therefore far back into time to see some of those early galaxies. The most distant of these have had their light stretched far into the infrared, and Hubble was blind to them. The earliest galaxy that Hubble spotted dated from 400 million years after the Big Bang.
That’s quite a substantial—and crucial—time gap of nearly 400 million years. During this time, matter was contracting, forming the first stars and galaxies. How did that happen? Without empirical data, computer models attempt to answer the question. But of course, all speculative models must accommodate themselves to hard data.
Within weeks of its deployment, JWST may have exploded the models. If the result holds up, a galaxy that began shining brightly when the universe was just 230 million years old has been detected. It doesn’t look like much. Keep in mind this is not its “true” color, which is invisible infrared.
https://www.science.org/content/article/webb-telescope-reveals-unpredicted-bounty-bright-galaxies-early-universe
And this galaxy is not alone. Webb has found far more galaxies in this early epoch than models ever predicted. Apparently galaxies formed more quickly than the models allowed. Back to the drawing board, indeed.
A couple of caveats:
- It’s possible that this first look just happened to land on an unusually rich cluster of galaxies.
- The ages of galaxies are determined from detailed study of their spectra. These first estimates are based on the apparent color rather than that more painstaking analysis. But dust in a galaxy can redden its light and make the galaxy look older than it really is.
You might think it would be disappointing to find the unexpected. Not true! New data, new questions, new discoveries to be made. JWST is already opening the door to a better understanding of the early universe.
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