Previous: A Tribute to John Glenn
Next: The Biggest-Ever Supernova, Debunked!



View count:170,637
Last sync:2018-05-10 19:00
Reports of a fireball streaking through the sky are never a good sign after losing contact with a rocket.

And what can science tell us about adorably tiny asteroids?

Want more SciShow in person? We'll be at NerdCon: Nerdfighteria in Boston on February 25th and 26th! For more information, go to

Hosted by: Caitlin Hofmeister
Support SciShow by becoming a patron on Patreon:
Dooblydoo thanks go to the following Patreon supporters—we couldn't make SciShow without them! Shout out to Bella Nash, Kevin Bealer, Mark Terrio-Cameron, Patrick Merrithew, Charles Southerland, Fatima Iqbal, Benny, Kyle Anderson, Tim Curwick, Will and Sonja Marple, Philippe von Bergen, Bryce Daifuku, Chris Peters, Patrick D. Ashmore, Charles George, Bader AlGhamdi
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:
Looking for SciShow elsewhere on the internet?

Image sources:
Caitlin: Even though we’ve launched hundreds of rockets, there’s really no such thing as an ordinary launch. Weather conditions, rockets, cargo — something’s always a little different every time. Unfortunately, that means things don’t always go as well as you’d hope.

On December 1st, the unmanned Russian cargo ship Progress 65 launched from Kazakhstan on a resupply mission to the International Space Station. The Progress capsule has been used for more than 150 successful missions, so you’d think it would’ve been business as usual. The mission was supposed to deliver more than 2 metric tons of equipment, food, and supplies to the six people in orbit right now.

But the ship never actually made it that far. Everything was going well until around six minutes into the launch. Suddenly, mission controllers lost contact with the cargo ship, and radar stations couldn’t find it on its planned trajectory. Then, reports came in from southern Russia about a fireball streaking through the sky. Which is never a good sign, really.

About 190 kilometers above Earth, Progress 65 was falling and burning up in the atmosphere. They’re still investigating exactly what happened, but the current theory is that the failure had to do with the Soyuz rocket that Progress was mounted on. Third stage separation, where the rocket and cargo ship break apart, was supposed to happen in orbit, but it looks like it happened early. And since Progress wasn’t in orbit yet, it fell back down to Earth, with most of the ship burning up in the atmosphere.

Thankfully, this all happened over an unpopulated region near the Russia-Mongolia border. Either way, there’s no need to worry about the astronauts aboard the Station. They prepare for situations like this, so they have plenty of food and supplies to hold them over until the next resupply mission arrives.

Progress failures are pretty rare, though: This is only the third failure in 156 missions. So hopefully they’ll figure out what caused the problem and solve it before the next Progress mission, which is set to launch in February.

Meanwhile, on a cuter note, astronomers have studied their tiniest asteroid yet, in a paper published last month in The Astronomical Journal. It’s called 2015 TC25, and at only 2 meters in diameter, it’s so small that you could basically ride it around the solar system! Which sounds adorable, and they should honestly check for a rose and a little prince on the surface.

The asteroid was discovered last year as part a larger asteroid study at the University of Arizona, and at the time, the little guy was zooming past Earth only 128,000 kilometers away, or about one-third the average distance from Earth to the Moon.

As it passed, the asteroid was observed using four telescopes, which collected optical, infrared, and radar data. It’s the first time we’ve have so many different kinds of observations of such a small asteroid!

Astronomers discover tiny near-Earth asteroids like this every year, but because they’re so small, they’re usually hard to characterize. But since this one was so close and was observed by so many telescopes, they could get the data they needed.

Besides being so small, 2015 TC25 is also one of the brightest near-Earth asteroids ever discovered! It reflects about 60% of the light shined on it, and researchers believe it’s similar to a rare kind of asteroid called an aubrite.

Aubrites are made of bright minerals — mainly silicates, which are silicon and oxygen salts. For comparison, similar non-aubrite asteroids only reflect 40 to 50% of the light that shines on them. This is also the first asteroid we’ve seen without regolith, a layer of loose, rocky material that covers other asteroids and larger bodies, like the moon.

It’s possible that all small asteroids are just bare rock, but we’ll have to observe more to be sure! And as if it weren’t cool enough already, this is also one of the fastest-spinning near-Earth asteroids we’ve found. It rotates about once every two minutes! Based on its composition, 2015 TC25 likely broke off from 44 Nysa, a much bigger asteroid in the main asteroid belt that’s about 70 kilometers wide.

Now, besides the cute factor, there are important reasons to study small asteroids. Asteroids have been around since the birth of our solar system, so studying them helps us learn more about how planets formed. And by examining these smaller rocks, we can collect information about their parent asteroids, which we might never be able to investigate up close. So, 2015 TC25 might be small. But what we’re learning from it is huge.

Thank you for watching this episode of SciShow Space. If you want more space news every week, you can go to and subscribe, and if you want more SciShow in person we’ll be at Nerd Con: Nerdfighteria in Boston on February 25 and 26th. Check out to learn more.