Space Photos of the Week: 2I/Borisov and Its Comet Buddies

Comets are like the holidays, they come and they go, only their role in the universe is a bit more perplexing than the annual family get together. They might have killed the dinosaurs (bad for them, good for us?). They also might have helped bring water to Earth and other planets. For all the unknowns surrounding comets, they are at least predictable in their orbits. Every year like clockwork, their long, icy tails deliver meteor showers: As Earth moves through the path of their tail, the rice-sized bits of dust and ice burn up in our atmosphere and look like shooting stars. That’s just one manifestation of the awesomeness of comets, the theme of our visual tour this week.

NASA’s Hubble Space Telescope has been keeping an eye on an interstellar visitor called Comet 2I/Borisov. It came from another solar system, and just a week ago Hubble spotted it sneaking into our neighborhood. At the time of the photo, Comet 2I/Borisov was a mere 200 million miles away from Earth. In the background, a very distant spiral galaxy appears blurry because Hubble was focusing on the comet. The tail of Comet 2I/Borisov is seen here swooping up and to the right.Photograph: NASA/ESA/D. Jewitt (UCLA)/CC BY 4.0

Comet C/2018 Y1 Iwamoto is what astronomers call a long-period comet, because of its 1000-year orbit of the sun. The comet originates from the Oort cloud, a massive, donut-shaped ring of ice, rocks, and icy rocks on the edge of our solar system. This photo shows the comet with four different exposures in the infrared, which shows us how cold the comet is—in this case near freezing.Photograph: NASA/JPL-Caltech

The European Space Agency dispatched a spacecraft called Rosetta to orbit this celestial snowball, Comet 67P/Churyumov-Gerasimenko, for many years. The comet is only about the size of downtown Los Angeles, but it packs in many scientific treats. As comets orbit closer to the sun they “off-gas,” which is a fancy way of saying they melt and release their water vapor, leaving a tail behind them. The Rosetta mission, which collected this photo, discovered a lot of water on 67/P.Photograph: ESA/Rosetta/MPS for OSIRIS Team

Halley’s Comet, one of the most famous, last flew close to Earth in 1986, when this image captured the comet and its tail. Halley is a short period comet, coming close to Earth around every 75 years, so you might have a chance to see this in your lifetime with the naked eye. But that won’t be until 2061, so eat your vegetables.Photograph: W. Liller

Before scientists spotted its tail, scientists thought Comet P/2016 BA14 was an asteroid. Although it looks like a small sugar cube in this series of radio images, comet P/2016 BA14 is about 3,000 feet in diameter. It orbits pretty close to Earth and Jupiter, making it one of the few comets to stay in the main part of the solar system.Photograph: NASA/JPL-Caltech/GSSR

Orbit on over to here to peer at more celestial bodies.