What the Webb Telescope Images Didn’t Capture

Like many others, I have spent a great deal of the last few days staring slightly slack jawed at the first stunning images the James Webb Space Telescope delivered on July 12th. They display the beauty, complexity, and elegance of the universe in ways that have stopped even the most experienced astronomers in their tracks.

But one thing nags at me, one thing that these images, and almost all astronomical images, often fail to capture about the universe: its movement. These still frame images give the impression that the universe is a static, calm place. But nothing could be further from the truth. The universe is a fundamentally dynamic place, constantly changing and evolving. Planets spin as they orbit around stars. Stars send shockwaves into their surroundings as they explode as supernovae. Galaxies stretch, twist and warp each other as their mutual gravitational forces draw them together. And the very universe itself is expanding, propelled by the mysterious dark energy.

In many of these cases, the timescales are simply too long for humans to be able to observe the movement directly. But the trained eye can learn to notice the hints of movement and see the universe at work right before you. Here, I offer a short commentary on signs of movement and change in a handful of images from the Webb Telescope.

Deep Field Image: Expanding Universe Pulls Galaxies

Deep field images, like this one, look at small, blank areas of the sky with very long exposure times in order to capture the faintest, most distant objects possible. Every dot, blob and smudge you see in this image is a galaxy (with the exception of the handful of spikey stars), which itself contains millions or even billions of stars. Take a moment and notice how many of these galaxies are orange or red— it’s a lot. These galaxies are not actually emitting red light, they only appear red because they are being dragged away from us by the expansion of the universe. Just as the horn of a train drops in pitch as it chugs past, light from galaxies gets stretched and reddened as they are pulled away from us. [Not to mention that Webb detects infrared light, which is already longer and redder than our eyes can detect.] So the red hue of the galaxies tells us that they are racing away from us at over 100 million m/s!

These five galaxies may look friendly, but four of them are in the process of tearing each other apart. The gravity of these massive galaxies tug and pull on each other, often peeling off trails of gas and stars in the process. As they merge together, new star formation is prompted in clouds of gas and dust that are compressed by shockwaves. And finally the central black holes of each galaxy begin to swing wildly past each other before spiraling into each other and releasing powerful gravitational waves. Galactic collisions and mergers like this one are a vital part of the galactic evolution process.

The Southern Ring Nebula is a planetary nebula, which is a misleading name considering it has nothing at all to do with planets. When a small star runs out of fuel in its core, it starts shedding its outer layers, which float away gradually. Left behind is the tiny glowing core of the star known as a white dwarf, which you can see at the very center of the nebula. The white dwarf’s fading light illuminates and excites the outer layers, making them glow in brilliant colors, as they float outward. The nebula may seem serene, but it is in fact expanding outward at nearly 20 miles per second!

The gorgeous Carina Nebula image shows an expanse of hydrogen gas with peaks and valleys reminiscent of a terrestrial landscape. And in some ways, it is very similar to earth’s surface because these features have been carved by powerful stellar winds ejected from the young stars that are just beyond the top of the frame. Just like a picture of leaves suspended above the ground indicates the presence of wind, the peaks and finger-like projections tell us that a steady stream of charged particles and atoms are blasting into the nebula at up to 1000 miles per hour. This is one windy nebula!