Hi, I'm Erin McCarthy, editor-in-chief of Mental Floss.com Welcome to Mental Floss video and did you know that if you brought a block of lead to Venus it would melt like a block of ice on earth?

Of course *you* couldn't bring a block of lead to Venus for many reasons, including the fact that the surface temperature is around 900 degrees Fahrenheit. Even spacecraft that get sent to Venus aren't able to withstand the environment for long.

The Soviet Union's Venera 13, for example, landed on Venus in 1982 and lasted about two hours before its demise. Though the Venera was able to send back the first color images of the planet and analyse its soil, so all in all, a pretty productive visit. And that's just the first of many out-of-this-world facts about the solar system that I'm going to share with you today.

An important question to begin with is, "What is the solar system?" Well, it's a group of celestial bodies in the Milky Way galaxy. At its center is a 4.5 billion year old star, aka our Sun, that is orbited by eight planets, over 150 moons and millions of meteoroids, comets, and asteroids- plus a few dwarf planets. That sounds impressive but it's just one of tens of billions of solar systems that scientists estimate can be found within the Milky Way.

We happen to know the most about our own, though, so that's the one we're talking about today. Let's start with our Sun, which is huge. If you combine the mass of everything in the solar system, the Sun would account for more than 99% of that mass.

Jupiter is massive. It's large enough to fit all the rest of the planets inside of it, or put another way, it would take 1300 earths to fill up the inside of Jupiter. And while we're playing that game: even Jupiter's red spot is larger than Earth...sometimes.

The red spot is a storm containing winds up to 400 miles per hour that heats the atmosphere above it to 2,400 degrees Fahrenheit, and its size isn't constant. In fact it's currently getting taller but smaller in width. Another shrinking part of our solar system is Mercury.

Like Earth, Mercury experiences tectonic activity. Pictures taken of the planet have indicated that the surface is changing. The planet has a solid inner core that's surrounded by a liquid metal outer core which is in the process of cooling.

Every rocky planet is still cooling from when they initially emerged, and as the liquid parts of Mercury's core become solid there's contraction, leading to land shifting and a smaller planet overall. The dwarf planet Eris, which was discovered in 2005, was indirectly responsible for Pluto's demotion to a dwarf planet. Eris is comparable in size to Pluto, which threw astronomers into a tizzy.

They worried about how many newly discovered bodies orbiting the Sun might have to be considered planets. After Eris's discovery the International Astronomical Union created new planet standards. "To be considered a planet now a celestial body must be round, orbit the Sun and clear its orbit of smaller objects." Around the time that Eris was discovered so was another dwarf planet: Haumea. It's a weird looking place.

It spins so fast that it's shaped like a football or plump cigar, as NASA describes it. Haumea completes a rotation in under four hours. I often tell people that I will never go to space and the reason why boils down to two words: space junk.

Between meteoroids and debris created by humans, NASA knows of over 20,000 pieces of space junk bigger than a softball orbiting the Earth. And that's out of 500,000 total pieces they track. Each one of those pieces is at least as large as a marble.

There are millions of pieces so small that it's not possible to track them. According to the agency, man-made space junk includes quote "non-functional spacecraft, abandoned launch vehicle stages mission related debris and fragmentation debris." This stuff can be moving at more than 17,500 miles per hour, so even something as small as a chip of paint can do damage to operational spacecraft, and sometimes the International Space Station has to maneuver to get out of the way of space junk. Beyond the danger to spacecraft some scientists are worried about a thing called Kessler Syndrome, which is when there's so much debris in low-earth orbit that it all starts bumping into each other, creating more debris.

Think of it like the domino effect, but in space- so...terrifying. The European Space Agency has proposed cleaning up space junk via nets. A team at Texas A&M University has suggested sending a mechanism to space which would push objects into Earth's atmosphere where they would burn up, then use the momentum from the pushes to travel from debris to debris.

Okay: space junk rant over. In 2008 an object was discovered that orbits the Sun at about a 104 degree tilt. Technically, this means that the 30 mile wide object is orbiting backwards. The team that discovered it gave it the name Drac based on the myth that Dracula could walk up walls.

Is it weird that that makes him less scary to me? The object was found in the Kuiper belt which is an area of our solar system past Neptune containing a lot of icy objects. The Kuiper belt is also where Pluto lives.

Interestingly, Neptune has a moon called Triton that's a lot like Pluto, so Triton is probably one of those icy Kuiper belt objects that at some point got trapped by Neptune's gravity and has been orbiting it ever since. Triton has a couple other distinctive features: it orbits Neptune in the opposite direction than the planet is rotating, and it has geysers that erupt. (That's my geysers erupting.) It's Ben Affleck on an asteroid. So about

Pluto: some claim that the planet was named after the Walt Disney dog who appeared the same year that the dwarf planet was discovered: 1930. But in 1930's The Picnic the dog was called Rover. He wouldn't be known as Pluto until 1931, the year after the discovery of the planet. Still, there's a fun coincidence that links Pluto the dog and Pluto the dwarf planet.

In 2015 NASA released new photos of Pluto which revealed a light area that some said looked like an image of the dog's head. Pluto's fellow dwarf planet Ceres takes up about 25% of the mass of the main asteroid belt which is located between Mars and Jupiter. In the 19th century Ceres was considered a planet, then it was demoted to an asteroid, and finally, in 2006, it was upgraded to dwarf planet.

You go, Ceres! There are millions of asteroids in the same belt as Ceres. They can range from less than 33 feet to 329 miles long.

NASA keeps an ongoing list of asteroids with the potential to hit earth in the next century, along with the probabilities of that happening. They're keeping a list because they (singing) don't want to miss a thing. ... And by a thing I mean an asteroid.

One of Saturn's moons Enceladus has water. It has an entire ocean made up of salt water. In 2018 researchers found complex organic molecules on Enceladus which is a sign that it could potentially contain life... or not.

That's why there are proposals to send a mission there to find out. Saturn has a second moon with water, Titan, which also has carbon containing chemicals, another promising sign for life. Any place that has both water and carbon- containing chemicals is very exciting to researchers who are interested in finding life in other places out in space.

I've already mentioned the extreme temperatures of Venus and Jupiter. Mars would give human visitors similar issues. Compared to Earth's average temperature of 57 degrees Fahrenheit, Mars is at negative 81.

At the poles a temperature of negative 225 degrees is possible. There's also been no rain on the planet for millions of years, which is hell on. Martian lawns.

But if we could figure out that temperature issue it would be totally worth it to go to Mars to see Olympus. Mons, the tallest volcano we know of. It's estimated to be 16 miles tall, meaning it's basically three Mount Everests.

It probably formed around 350 million years ago, but it last erupted as recently as 2 million years ago. We have billions of comets in our solar system, mostly in the Kuiper belt and the Oort Cloud. A comet is made of ice and rock until it gets close enough to the Sun and then the exterior turns into a cloud of gas and dust.

That's when the distinctive tail forms. In 2014 a probe landed on a comet for the first time. Here's one interesting piece of information gathered from that mission: due to the chemistry of its surface, a comet smells like cat pee, rotten eggs, and bitter almonds.

So maybe think twice before picking up any comet- scented candles. Finally, so many of these facts would still be unknown if it wasn't for the amazing space exploration that has taken place over the years. I can't tell you about all of the missions so I'm just gonna tell you about the.

Cassini spacecraft, which launched in 1997 and didn't stop collecting data until 2017. In those twenty years it traveled four point nine billion miles and completed 2.5 million commands. Most of that time was spent around Saturn, doing everything from taking pictures to gathering data to analyzing samples.

Cassini was sent into Saturn's atmosphere to disintegrate on September 15th, 2017. At a press conference Cassini's program manager Earl Mays said, quote, "To the very end the spacecraft did everything we asked." Aww.. Thanks for watching Mental Floss video, which is made with the help of all of these nice people.

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