Astonishing interstellar comet captured in new images by NASA Mars missions
The latest images of an interstellar comet shared by NASA have shown how an ensemble of spacecraft witnessed a truly out-of-this-world flyby., revealing clues about the composition of the object, revealing clues about the composition of the object.
Astronomers first detected the rare comet, known as 3I/ATLAS, on July 1. This is only the third observed interstellar object, or ISO, to come from outside our solar system and pass through it.
When the interstellar comet flew past the Red Planet in October, several NASA missions abandoned their explorations to capture tantalizing images of the object originating from outside our solar system.
Stacked images from 3I/ATLAS, taken by the Solar Terrestrial Relations Observatory spacecraft, show it at a speed of 130,000 miles per hour in September. – NASA/Lowell Observatory/Qicheng Zhang
The US space agency released new observations on Wednesday, as it was unable to share them during the government shutdown.
Although none of the spacecraft have cameras perfectly designed to spot comets passing at speeds up to about 153,000 miles per hour (246,000 kilometers per hour), astronomers didn’t want to miss what could be a once-in-a-lifetime opportunity.
“It’s a bit like our NASA spacecraft going to a baseball game and watching the game from different locations in the stadium,” said Tom Statler, lead scientist for small bodies in the solar system at NASA. “Everyone has a camera and is trying to take a picture of the ball and no one has a perfect view, and everyone has a different camera.”
The Lucy spacecraft captured a faint halo of gas and dust around the comet on September 16. – NASA/Goddard/SwRI/JHU-APL
Missions capture images of rare interstellar comet
Nearly 20 mission teams collaborated to capture images of the comet, said Nicky Fox, associate administrator for NASA’s Science Mission Directorate.
“Everything we learn about the comet is possible because of the distribution of all the different instruments on our spacecraft with different capabilities,” Fox said. “We even pushed our science instruments beyond what they were designed for, to allow us to capture this incredible glimpse of this interstellar traveler.”
Before the Mars flyby in September, spacecraft Lucy and Psyche, en route to study asteroids, and sun-focused missions like the Parker Solar Probe, SOHO and PUNCH, spotted the comet in action.
Combining data from Lucy and Psyche with ground-based telescopes can reveal more about the comet’s three-dimensional structure and the nature of the dust that sheds from it due to the sun’s heat, Statler said.
“This is a rare opportunity to compare ancient dust from a distant solar system to that of our own,” he said.
3I/ATLAS appears as a faint speck against a background of stars from the perspective of the Perseverance rover on October 4. – NASA/JPL-Caltech/ASU/MSSS
The Mars Reconnaissance Orbiter and Perseverance rover also tracked the comet as it flew past the Red Planet in October. The orbiter was the physically closest spacecraft to the comet, Fox said.
The comet arrived at its closest point to the sun when Earth was on the wrong side for ground-based telescopes to easily observe it, but Mars had optimal viewing conditions, according to Statler. “Our Mars equipment was able to observe the comet, and several of our other spacecraft were also on the right side of the sun,” he said. “We couldn’t get this view from Earth.”
Two spacecraft that will study Jupiter and its moons, the European Space Agency’s Europa Clipper and Jupiter Icy Moons Explorer, or Juice, and Europa Clipper, will also aim to capture the comet’s movements as it approaches Jupiter’s orbit in the spring.
The comet came within approximately 29 million kilometers of Mars on October 3. ESA’s ExoMars Trace Gas Orbiter, which has been circling the Red Planet since 2016, was about 10 times closer to the comet than Earth-based telescopes – and it captured images from an angle that Earth-based telescopes couldn’t see. The new perspective of 3I/ATLAS allowed scientists to predict the future trajectory of the comet with increased precision.
A host of other spacecraft, including the Hubble and James Webb space telescopes, have also observed the object.
As scientists use telescopes around the world to study 3I/ATLAS, space missions offer key observational advantages, said Dr. Theodore Kareta, a planetary astronomer and assistant professor in the department of astrophysics and planetary sciences at Villanova University in Pennsylvania.
Cameras and instruments on different spacecraft are aimed at various lenses and measurements, and can provide distinct viewpoints that would otherwise be impossible to capture, he said.
“Comets are three-dimensional objects, and looking at them from different angles will give us a much clearer picture of not only where they are and what trajectory they are following, but also the size of the comet’s nucleus and the nature of the structures or patterns we can see in its atmosphere,” Kareta said.
Scientists currently think the comet is between a few thousand feet and a few kilometers in diameter, but they are still refining their measurements, Statler said.
Psyche tracked 3I/ATLAS for eight hours on September 8 and 9, when the comet was about 33 million kilometers from the spacecraft. -NASA/JPL-Caltech/ASU
The behavior of a comet
NASA officials were quick to respond to rumors circulating around the interstellar nature of the comet, including the idea that it was an alien spacecraft.
“It looks and behaves like a comet, and all the evidence points to it being a comet,” said NASA Associate Administrator Amit Kshatriya. “But this one comes from outside the solar system, which makes it fascinating, exciting and scientifically very important.”
Fox said NASA’s close monitoring of the comet since its discovery has yielded no evidence that could lead them to believe it was anything other than a natural celestial object, such as technosignatures — a signal that could be created by extraterrestrial life.
“But what’s super cool is not that it’s exactly like all the comets we see in our solar system,” Fox said. “It’s the differences that attract us the most.”
Kshatriya said he was actually excited to see much of the world speculating about the comet while NASA was unable to share comments on it due to constraints from the recent shutdown.
“It got people thinking about the magic of the universe,” he said. “Actually, we really want to find signs of life in the universe. But 3I/Atlas is a comet.”
Comparison of 3I/ATLAS with more common comets
The comet came closest to the sun on October 30, coming within 130 million miles, according to NASA.
A comet from our solar system is like a dirty snowball. Its core, or solid core, is a frozen mixture of rocks, gas, dust and ice from the formation of stars, planets and other celestial bodies. As comets approach stars like our sun, they heat up, forming tails of sublimating material that extend behind them.
The MAVEN orbiter captured the comet in ultraviolet light, spying on its hydrogen atoms on September 28. -NASA/Goddard/LASP/CU Boulder
Since 3I/ATLAS comes from another solar system, astronomers are eager to see how different or similar its composition is to the comets they are used to observing.
3I/ATLAS released more carbon dioxide than water and more nickel than iron, compared to comets native to our solar system – a topic that is still being studied, Statler said.
The comet also showed increased activity, leading some observers to wonder whether the object broke up during its close passage of the sun.
The observed “jets” emitted by the comet may mean that there are particularly active areas on the comet’s surface where more material is evaporating than elsewhere, Statler said.
“Comets frequently exhibit ‘jets’ or ‘spirals’-like features in their internal atmospheres, related to which parts of their surfaces are active and releasing gas and dust, so photographing them from just one angle can be difficult to interpret,” Kareta added.
Today, the object is starting to reappear on the other side of our star for terrestrial telescopes. The object will move within 270 million kilometers of Earth on December 19 before beginning to exit our solar system.
The SOHO mission spied the comet between October 15 and 16. – Lowell/Qicheng Zhang Observatory
“The fact that so many NASA missions have attempted to observe this interstellar visitor should tell you how seriously we all take this opportunity,” Kareta said. “Interstellar objects like 3I/ATLAS are inherently rare, and ISOs as bright as 3I should be even rarer – this object could very well be the ISO we learn the most about for many years to come.”
Although the comet’s exact age is unknown, the object’s speed suggests it is much older than anything in our solar system, Statler said.
“3I/ATLAS is not just a window into another solar system, it’s a window into a deep past – and one so deep that it predates even the formation of our Earth and sun,” Statler said.
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