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Last week, Vice President Kamala Harris and French President Emmanuel Macron visited NASA headquarters to take a peek at a recent snapshot of two galaxies gracefully swirling together – a galaxy merger referred to as II ZW 96. 

Taken by the James Webb Space Telescope, this image of two galaxies colliding 500 million light years away is a beautiful but somewhat unsettling sight, providing a glimpse into our own galaxy’s violent future.

In about 2 billion years, the Milky Way will subsume the Magellanic Clouds, likely triggering an outburst from our central black hole. A few more billion years down the line, we will collide with the even more massive Andromeda. This rather transformative event will create one big elliptical galaxy, stripping the Milky Way of its signature spiral arms and black hole. (If anyone feels like creating a soundtrack for an end-of-the-galaxy blowout, I recommend indie musician Weyes Blood’s Andromeda.)

While II ZW 96’s entanglement is not so directly applicable to our fate, it serves as an excellent case study for research on galactic evolution and star formation rates. As the two spiral galaxies twist together, their bright cores sandwich an extremely luminous region of intense star formation. 

Such high rates of star formation define starbursts, which are typically caused by two gas-rich spiral galaxies merging. This skyrocketing star birth rate is the result of a sudden increase in baby star fuel–i.e. extreme concentrations of gas and dust that coalesce as the galaxies blend together. 

Webb’s infrared cameras are perfectly suited for capturing starbursts: high energy mergers typically radiate most strongly in the infrared, and are frequently visibly obscured behind all of that dust. This image of II ZW 96 was taken by its near-infrared camera, which covers a wavelength range in which obscuring dust becomes transparent, revealing strongly glowing star-forming regions. II ZW 96 was also observed in the mid-infrared; this provided a closer look at the obscuring dust itself, which warms up and re-radiates heat at these wavelengths.

As fascinating as these high-energy case studies may be, galaxy mergers are much harder to study on a more general level. This is not on account of the rarity of mergers, but the opposite: there are too many, and they take too much effort to identify. 

Many celestial objects can be classified by spectroscopy or photometry, techniques that provide information like chemical composition and brightness at certain wavelengths. Galaxy mergers, on the other hand, are mainly identified through visual inspection, which is time-consuming and not always accurate.

One solution to this is soliciting help from screen-addicted non-scientists, like you and me. The Galaxy Zoo Project is a so-called “citizen science project” in which volunteers can click through images of galaxies and help classify them. Next time you find yourself mindlessly and melancholily scrolling through social media, click over to Galaxy Zoo instead. You might just play a part in deciding Hubble or Webb’s next target. 

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Georgia Michelman is a reluctant recent Yale College graduate with backgrounds in physics, astronomy, and history. She is always searching for intersections between the worlds of science and the humanities....