Comet Leonard Seen Speeding Through Sky in Once-in-a-Lifetime NASA Images

Two sun-observing spacecrafts have caught a glimpse of Comet Leonard as it heads for a close encounter with our star on January 3, 2022.

The comet, also known as C/2021 A1, is the brightest object of its type to be seen over the skies of Earth in 2021, and spotting it has been a once-in-a-lifetime opportunity for skywatchers.

Following its early January close approach to the sun, when it will pass within 57.2 million miles of our star, not only will the comet pass out of view, but its discoverer astronomer and University of Arizona researcher Greg Leonard, predicts it will be heading out of the solar system altogether.

"This is the last time we are going to see the comet," Leonard said in a press release on December 13. "It's speeding along at escape velocity, 44 miles per second. After its slingshot around the sun, it will be ejected from our solar system, and it may stumble into another star system millions of years from now."

The first spacecraft to spot Comet Leonard as it undertook the final stages of its 40,000 year-long journey from the edge of the solar system to our star was NASA's Solar Terrestrial Relations Observatory-A (STEREO).

The STEREO mission has been observing the comet since November with its SECCHI/HI-2 telescope. After launching in 2006, the spacecraft is tasked with measuring the solar wind and magnetic fields between planets as well as catching images of the sun's corona and heliosphere.

Observations from STEREO were used to build an animation of Comet Leonard that shows changes in the comet's tail, created as radiation from the sun burns off ice and other material from its surface. This animation demonstrates how the comet's tail is becoming longer and brighter as it approaches the sun.

comet leonard nasa
An image showing subtle changes in comet Leonard’s tail over two frames, captured by the HI-2 telescope aboard NASA’s STEREO-A spacecraft. (NASA/NRL/Karl Battams) NASA/NRL/Karl Battams

In a separate video (seen at the top of this article) captured by the European Space Agency and NASA's Solar Orbiter spacecraft, Comet Leonard can be seen streaking diagonally past the craft's view of the Milky Way. Also visible in the video shot by the craft, which launched in February 2020, is Venus which the comet made a close passage to over December 17 and 18.

In the video shot on December 17 and produced by the Solar Orbiter Heliospheric Imager (SoloHI), Venus can be seen moving from left to right as the Solar Orbiter shifts into a side-on view of the comet, thus revealing more of its tail.

Comet Leonard will be tracked by SoloHI until it moves out of the instrument's field of view at some point on Wednesday.

Comet Leonard is currently undergoing outbursts of brightness that seem to be ice and dust being liberated from the comet's nucleus by the heat of the sun, which could even be causing large chunks of material to be blown away.

NASA says that if the comet survives its close encounter with our star it will be flung into the solar system never to return, echoing the opinion of Leonard, who discovered the comet in January this year.

Comet Leonard
Two images of Comet Leonard as captured by NASA’s Solar Terrestrial Relations Observatory-A spacecraft and the ESA/NASA Solar Orbiter spacecraft as it heads towards the sun. the comet will soon leave our solar system never to return. NASA/Getty/ESA/NASA/NRL/SoloHI/Guillermo Stenborg/ Franco Tognarini