Watch Live as Interstellar Comet 3I/ATLAS Makes Its Closest Approach to Earth
For the past five months, astronomers around the world have carefully tracked a strange visitor from another solar system as it enters our own. Now, it will be very close to Earth.
Interstellar comet 3I/ATLAS will fly by our planet at a safe distance of 1.8 stellar units (about 167 million miles or 270 million kilometers) at 1 a.m. ET on Friday, December 19, according to calculations by NASA’s Jet Propulsion Laboratory. That’s almost twice the average difference between the Earth and the Sun.
You won’t be able to see 3I/ATLAS with the naked eye, but you can glimpse it in the predawn sky using high-powered binoculars or backyard binoculars.
If you want a clearer view, the Virtual Telescope Project 2.0 will host a live broadcast of the flyby starting at 11 pm ET on Thursday, December 18, and you can watch it below. The astronomy program, managed by the Bellatrix Astronomical Observatory in Italy, uses remote-controlled telescopes to provide real-time observations of the universe.
The epic 3I/ATLAS tour
This comet is considered “interstellar” because it comes from another star system. 3I/ATLAS is only the third astronomers have ever discovered, following ‘Oumuamua in 2017 and 2I/Borisov in 2019. Spotting one provides a rare opportunity for researchers to study a real sample in a far corner of the galaxy that current spacecraft cannot reach.
Friday’s 3I/ATLAS fly-by will be especially useful for science. This will be the best chance for astronomers to observe the comet and gather information before it leaves our solar system forever. In the months since the NASA-funded ATLAS observatory discovered 3I/ATLAS on July 1, researchers have been working tirelessly to study its chemistry and composition.
Their findings have led to many theories about the origin of 3I/ATLAS. Some previous research suggested that it came from an ancient star system in an area of the Milky Way called the thick disk. This region surrounds a small disk (where our solar system lies) and contains old stars. A recent study disputed this idea, instead pointing to a thinner disc.
Even if astronomers can’t narrow down the origin of 3I/ATLAS further, studying its properties can tell us more about what its home system is like. For example, researchers have found that the comet is full of carbon dioxide, suggesting that it formed in an environment with higher radiation levels than our own solar system.
3I/ATLAS zooms through space very quickly—it reached its maximum speed of 153,000 miles per hour (246,000 kilometers per hour) when it made its closest approach to the Sun in late October. After Friday, it will slowly fade into the distance as it moves deeper into the outer solar system, so you won’t want to miss this opportunity to see it up close—by comparison.
A stargazer’s guide to seeing 3I/ATLAS
If you want to see 3I/ATLAS with your own telescope or binoculars, here’s everything you need to know.
Your best chance to see the comet will be during the pre-dawn hours, about 90 minutes before sunrise. According to BBC Sky at Night Magazine, you can find it in the morning sky by finding the constellation Leo, then looking to the lower left of its brightest star, Regulus, and the Sickle asterism.
Specifically, you’ll need to star jump with your telescope from Regulus to the magnitude 3.8 star Rho Leonis, then look half that distance in the same direction until you see a thin, misty nebula. With binoculars, it will appear slowly.
There are many astronomy apps available that can help you find comets, such as Stellarium or SkyView. But if you want to save yourself the trouble, you can see 3I/ATLAS in more detail via the Virtual Telescope Project live stream. No matter how you choose to view, witnessing a rare and scientifically amazing phenomenon will be worth it.
