Astronomy Picture of the Day

Explanation: It came from outer space. An object from outside our Solar System is now passing through at high speed.Classified as a comet because of its gaseous coma, 3I/ATLAS is only the third identified macroscopic object as being so alien.The comet's trajectory is shown in white on the featured map, where the orbits of Jupiter, Mars, and Earth are shown in gold, red, and blue.Currently Comet 3I/ATLAS is about the distance of Jupiter from the Sun -- but closing, with its closest approach to our Sun expected to be within the orbit of Mars in late October.Expected to pass near both Mars and Jupiter, 3I/ATLAS is not expected to pass close to the Earth. The origin of Comet 3I/ATLAS remains unknown.Although initial activity indicates a relatively normal comet, future observations about 3I/ATLAS' composition and nature will surely continue.