[♪ INTRO] In science fiction, whenever an asteroid is  headed toward Earth, a team of scientists shows up and dramatically finds a way to  destroy the asteroid or blast it away.

But soon… we will see if that  idea also holds up in reality. As early as November 24th, NASA will launch the Double Asteroid Redirection  Test mission, also known as DART.

And it’s going to do just what the name  says: It will attempt to show whether or not we could knock an asteroid  off-course if we really needed to. And yes, this does sound like the plot of the  movie Armageddon, but it is not science fiction: If all goes well, DART will  intentionally crash into an asteroid next September and change its orbit. Now to be clear, the asteroid in question  is not on a collision course with Earth.

As far as we know, there are no asteroids  that could cause widespread damage scheduled to hit the earth in the next 100 years. But we do not and should not have to wait  for a threat to start preparing for it. So, scientists have picked out the  perfect scapegoat to test DART on: a 160-meter wide moonlet  orbiting the asteroid Didymos.

The moonlet is officially called Dimorphos,  although some people are calling it “Didymoon.” What makes this moonlet such a great  choice is that at the time of impact, it’ll only be around 11  million kilometers from Earth. That means it’ll be possible to use  ground-based telescopes and radar to see what happens after DART hits it. The spacecraft has a mass of about 550  kilograms, and will be going around 24,000 kilometers per hour when it  deliberately crashes into the moonlet.

But even then, scientists expect Didymoon’s  orbit to change by less than one percent. They estimate that it will start orbiting  Didymos a whole ten minutes faster than usual. Which shows you what kind of power we  would need to deflect a big asteroid.

Still, this is just a test. The mission will help scientists understand how much momentum is required  to alter an asteroid’s orbit. And when all is said and done, we will know  whether shooting a spacecraft at an asteroid to knock it off course is more  science fiction or more science fact.

Which someday might come in handy. Meanwhile, on a much larger  scale, scientists recently stumbled upon a planetary system  that is throwing them for a loop. So, in our solar system, the  planets generally orbit the Sun in the same flat plane along the Sun’s equator.

And that matches what scientists have found  in a lot of other planetary systems, too. But then… there are some oddballs... Like, last month in the journal of Astronomy &  Astrophysics, researchers announced that they had found the first system with planets that  have orbits roughly perpendicular to each other.

The three planets in question orbit the  star HD3167 in the constellation Pisces, about 150 light-years from Earth. In 2019, scientists observed the two outermost  planets orbiting the star in a weird way: traveling vertically over the star’s poles,  instead of going horizontally around its equator. This is kind of strange, because  most scientists think that planets form from a spinning disk of matter  left behind after a star forms.

That disk spins out from the star’s equator, so it makes sense that the planets would  form and orbit along the equator, too. That said, planets with a polar  orbit have been seen before. So, this didn’t like break physics or anything.

But that’s not where the story ends. In this new study, researchers  pinpointed the movement of the third planet in that system as  well, and it was a bit of a surprise. So, this planet is the one closest to the star;   close enough that it orbits  it once every 23 hours.

The planet is also considerably  smaller than the other two. But the real surprise was that it  behaved like planets in our solar system: It orbited along the star’s equator,  which also meant it was orbiting at a roughly 90-degree angle to the  other two planets in the star system. So, very hypothetically, if you were standing on  this innermost planet, looking through binoculars at the other two, you would see  them move vertically through the sky rather than traveling across it horizontally.

Now, the big question is how  these planets ended up that way. Now the researchers don’t know for sure, but  their findings suggest that there might be something out there whose gravity is  tugging on the two outermost planets and pulling them into polar orbits. For example, while doing mathematical  analyses for a previous study, researchers found some  evidence that there could be a relatively large planet orbiting  this star, or even a brown dwarf.

That’s sort of an in-between object, bigger  than a gas giant and smaller than a star. Regardless, if this fourth body exists, scientists  think its gravity might have been enough to yank the outermost planets into a different orbit…  but not enough to affect the innermost planet. Because /that/ world orbits so close to its star, and at that distance, the star’s  gravitational pull would dominate.

To figure out whether or not this other body  exists, researchers are gonna need to continue observing the star for any tiny  movements that would happen as this other object’s gravity tugs at it. And that, they say, will take some time. But in the meantime, the researchers  say that this discovery reminds us that space is a lot more  complicated than we might imagine.

Turns out all kinds of solar systems are possible, and ones like this might even  be more common than we think. Thanks for watching this episode of SciShow Space! If you would like to help support the channel,  you can check out Patreon.com/SciShowSpace.

Yes, we have our own patreon for this channel, so if you love yourself some  space news, check it out. [♪ OUTRO]