21/Borisuv, the recently detected interstellar comet that entered our solar system, seems to be very similar to comets from our own system, with a coma and tail. This is in contrast to the first such visitor, 'Oumuamua, the bizarre cigar-shaped object that caused some to wonder if it could be an alien probe.
Discovered by a Crimean amateur astronomer who built his own telescope, 21/Borisuv "appears to be a completely unremarkable comet on a very remarkable orbit," Edinburgh University scientist Colin Snodgrass told the Guardian. Because the interstellar object looks just like our homegrown comets, it suggests that other solar systems might share the same building blocks as us.
Inbound toward the sun, 21/Borisuv will approach no closer than 190 million miles to Earth in December. Though it won't be visible to the naked eye, mid-sized telescopes can track it through April 2020. A Polish research team has tentatively pinpointed the comet's origin as Kruger 60, a star system with twin red dwarves, some 13 light years away.