A comet from outside our solar system is likely the oldest ever seen. Comet 3I/ATLAS was first seen on July 1 as it entered our solar system. It may even be older than our solar system.
3I/ATLAS is only the third object ever seen entering our solar system from outside. Previously, 1I/’Oumuamua (in 2017) and 2I/Borisov (in 2019) were seen as ‘visitors’ from outside our solar system. But 3I/ATLAS is much larger, and now appears to be much older.
The comet consists mainly of ice and other frozen substances. It may have formed 7 billion years ago, say astronomers from the University of Oxford. That would make the comet about 2.5 billion years older than the solar system it is now racing through. That would immediately make the comet the oldest object in our solar system ever.
“All non-interstellar comets, such as Halley’s, have formed within our solar system. As a result, they are no older than 4.5 billion years,” explains research leader Matthew Hopkins. “But visitors from outside the solar system can be much older. Our data indicate that 3I/ATLAS is probably the oldest comet we have ever seen.”
3I/ATLAS was first seen on July 1. It is flying approximately 490 million kilometers from Earth, at a speed of 58 kilometers per second. It is nowhere near on course to collide with Earth. The comet is now about as far from the sun as the planet Jupiter.
When the comet gets closer to the sun, the heat from the star will cause it to begin to melt. Then the comet will get the characteristic ‘tail’ of vapor and dust behind it.
