Comets Archives

August 25, 2020August 25, 2020 by Nancy Atkinson

Everyone Took Pictures of Comet NEOWISE, Including Hubble

This ground-based image of comet C/2020 F3 (NEOWISE) was taken from the Northern Hemisphere on July 16, 2020. The inset image, taken by the Hubble Space Telescope on Aug. 8, 2020, reveals a close-up of the comet after its pass by the Sun. Hubble’s image zeroes in on the comet’s nucleus, which is too small to be seen. It’s estimated to measure no more than 3 miles (4.8 kilometers) across. Instead, the image shows a portion of the comet’s coma, the fuzzy glow, which measures about 11,000 miles (18,000 kilometers) across in this image. Comet NEOWISE won’t pass through the inner solar system for another nearly 7,000 years. Credits: NASA, ESA, STScI, Q. Zhang (Caltech); ground-based image copyright © 2020 by Zoltan G. Levay, used with permission.

This summer we were (finally) treated to a spectacular, naked-eye comet, C/2020 F3 NEOWISE. And while seeing it with our own eyes was a joy, it was incredible to see the varied photos of NEOWISE taken by people around the world, showing the comet’s long gossamer tails, filled with detail and color. (See our gallery of images here.)

Now, the Hubble Space Telescope has released a high-resolution image of NEOWISE. However, it might not be the view you may have expected.

July 22, 2020July 22, 2020 by Evan Gough

Organic Matter Could Have Delivered Earth’s Water

This view of Earth’s horizon was taken by an Expedition 7 crewmember onboard the International Space Station, using a wide-angle lens while the Station was over the Pacific Ocean. A new study suggests that Earth's water didn't all come from comets, but likely also came from water-rich planetesimals. Credit: NASA

The origin of Earth’s water is a big piece of the puzzle in Earth’s history. Did it come from comets and asteroids? From water-bearing space dust? The scientific debate is not settled.

Now a new study shows that water could have been delivered to Earth by organic matter.

July 13, 2020July 13, 2020 by Evan Gough

Parker Solar Probe Gives a Unique Perspective on Comet NEOWISE

This unprocessed image from NASA’s Parker Solar Probe shows comet NEOWISE on July 5, 2020, shortly after its closest approach to the Sun. Credits: NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher

Comet watchers have enjoying the newly-discovered NEOWISE comet since it was first spotted in March 2020. Now that it’s visible with the naked eye, in dark sky conditions, all kinds of Earthly observers are checking the visitor out.

But NASA’s Parker Solar Probe has another view of the comet, one denied to Earth-bound observers.

July 9, 2020July 9, 2020 by Paul M. Sutter

Finally! We’ve got a comet that’s visible to the unaided eye. Comet C/2020 F3 NEOWISE

Comet NEOWISE as seen from the International Space Station in a photograph shared by Russian cosmonaut Ivan Vagner on July 4, 2020. (Image credit: Ivan Vagner/Roscosmos/NASA)

Look up! A rare naked-eye comet, C/2020 F3 (NEOWISE), is now visible to the unaided eye. But act fast – this celestial treat won’t last long.

April 21, 2020April 21, 2020 by Matt Williams

Interstellar Comet 2I/Borisov Formed in a Very Cold Environment

In the summer of 2019, a team of astronomers from NASA, the ESA, and the International Scientific Optical Network (ISON) announced the detection of the comet 2I/Borisov. This comet was the only second interstellar visitor observed passed through our Solar System, coming on the heels of the mysterious ‘Oumuamua. For this reason, astronomers from all over the world watched this comet intently as it made its closest pass to the Sun.

One such group, led by Martin Cordiner and Stefanie Milam of NASA’s Goddard Space Flight Center, observed 2I/Borisov using the ESO’s Atacama Large Millimeter/submillimeter Array (ALMA) in the Chilean Andes. This allowed them to observe the gases 2I/Borisov released as it moved closer to our Sun, thus providing the first-ever chemical composition readings of an interstellar object.

April 13, 2020April 13, 2020 by Evan Gough

When Comets Break Up, the Fragments Can Be Devastating If They Hit the Earth

Artist's conception of asteroids or comets bearing water to a proto-Earth. Credit: Harvard-Smithsonian Center for Astrophysics

Comet breakups are a timely topic right now. The interstellar comet 2I/Borisov just broke into at least two pieces. And though that comet is speeding out of the Solar System, never to be seen again, most of them don’t leave the Solar System. Most of them orbit the Sun, and return to the inner Solar System again and again.

A new paper examines the potential hazard to Earth from comets that break into pieces. The author makes the case that comet breakups could have had a hand in shaping the ebb and flow of life on Earth. It could happen again.

April 9, 2020April 9, 2020 by Evan Gough

Interstellar Comet 2I/Borisov Appears to Have Broken in Half

In 2019, amateur astronomer Gennadiy Borisov discovered a comet, which now bears his name. There’s a long history of amateur astronomers discovering comets, as they approach our inner Solar System on their elongated orbits. But this one was different: it was moving much too fast to be gravitationally bound to the Sun.

It was an interstellar comet. And now, it looks like it has split into two chunks.

January 23, 2020January 23, 2020 by Evan Gough

Rosetta Saw the Building Blocks of Life on Comet 67P

Comet 67P as seen by Rosetta on 7 July 2015. By ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0, CC BY-SA 3.0-igo, https://commons.wikimedia.org/w/index.php?curid=41733207

Why is there so little nitrogen in Comet 67P/Churyumov-Gerasimenko (67P)? That’s a question scientists asked themselves when they looked at the data from the ESA’s Rosetta spacecraft. In fact, it’s a question they ask themselves every time they measure the gases in a comet’s coma. When Rosetta visited the comet in 2014, it measured the gases and found that there was very little nitrogen.

In two new papers published in Nature Astronomy, researchers suggest that the nitrogen isn’t really missing at all, it’s just hidden in the building blocks of life.

December 10, 2019December 10, 2019 by Evan Gough

NASA’s TESS Watched an Outburst from Comet 46P/Wirtanen

Comet 46P/Wirtanen. Image Credit: By Stub Mandrel at English Wikipedia, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=75160399

TESS, the Transiting Exoplanet Survey Satellite, has imaged an outburst from the comet 46P/Wirtanen. It caught the outburst in what NASA is calling the clearest images yet of a comet outburst from start to finish. A comet outburst is a significant but temporary increase in the comet’s activity, outside of the normal sunlight-driven vaporization of ices that creates a comet’s coma and tail.

Astronomers aren’t certain what causes them, but a new study based on this observation is shedding some light on them.

November 29, 2019December 3, 2019 by Matt Williams

Interstellar Comet Borisov is About to Make its Closest Approach to Earth

Left: A new image of the interstellar comet 2l/Borisov. Right: A composite image of the comet with a photo of the Earth to show scale. (Pieter van Dokkum, Cheng-Han Hsieh, Shany Danieli, Gregory Laughlin)

On August 30th, 2019, astronomers with NASA, the ESA, and the International Scientific Optical Network (ISON) announced the detection of the interstellar comet C/2019 Q4 (2I/Borisov). News of the object was met with a great deal of excitement since it was only the second interstellar object to be detected by astronomers – the first being the mysterious object known as ‘Oumuamua (which astronomers are still unsure about)!

After a lot of waiting and several follow-up observations, 2I/Borisov is about to make its closest approach to Earth. To mark the occasion, a team of astronomers and physicists from Yale University captured a close-up image of the comet that is the clearest yet! This image shows the comet forming a tail as it gets closer to the Sun and even allowed astronomers to measure how long it has grown.