Every once in awhile, the stars actually do align — then merge, catastrophically explode, and spray their guts all over space.
Or at least that's the suspected trigger of rare "red novas," so-named for their characteristic red color.
One of the best-studied red novas happened in 2008. The object, called V1309 Scorpii, was a double-star system (also called a binary) measured for over 6 years before it merged and erupted.
But astronomers are desperate to find more such binary systems before they detonate, since watching the cosmic collisions would not only reveal a lot about the evolution of stars and nebulas, but also how space gets seeded with elements necessary for life.
Part of that effort has been a thorough search for binary star systems that look ready to blow.
However, Larry Molnar, an astronomer at Calvin College in Grand Rapids, Michigan, has gone a big step further with a few colleagues: Over the past 2 years, he's claimed not only to have found such a system, but also predicted when it will blow up as a red nova.
"No one has ever seen a star go into this kind of explosion. No other situation has come up where any astronomer has ever been able to say, 'this is a star about to blow up,'" Molnar said in a preview for an upcoming documentary, called "Luminous."
His prognostication is specific enough to make any astrophysicist squirm: Molnar now says the whole thing will go down just 5 years from now.
In fact, according to Molnar's prediction, the stellar outburst should be visible in the night sky without any help from binoculars or a telescope.
"[I]n the lack of viable alternatives we must take seriously the unlikely hypothesis at hand," Molnar told Business Insider in an email.
A dance of death
The stars in question are a system called KIC 9832227, and they're locked in a dance of death.
In fact, they're so close together that they share each other's million-degree-plasma atmospheres: an object called a "contact" binary.
If you could magically teleport to the system, which is located about 1,700 light years from us amid the constellation Cygnus, it might appear as a brilliantly glowing bowling pin.
But no one was certain that KIC 9832227 was actually a double-star system; all astronomers knew was that its brightness varied over the years. Many types of stars and star systems "pulsate" their brightness in this way, so Molnar and a Calvin College student had to first rule out any doubt that it was two stars.