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Ask Dr. Universe

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Ask Dr. Universe

Student-Led Podcasts | Explore the Solar System with PPCS

May 22, 2023 • Season 3 • Episode 7

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Welcome back, young scientists. I’m Dr. Universe. If you’re anything like me, you’ve got lots of big questions about our world.

Do you love our solar system? Today, 4th graders from Palouse Prairie Charter School take me on a space tour in their Boomcrusher space shuttle. Come along!

Ask Dr. Universe is a service of Washington State University geared toward an 8- to 13-year-old audience. If your class or group is interested in working on a podcast episode with Dr. Universe, reach out. It takes about 6 months for young scientists to research and write a script and then work through editing, factchecking, and recording.

Sound effects courtesy Zapsplat.com. Thank you to Dr. Michael Allen (WSU Physics & Astronomy) for factchecking and to Northwest Public Broadcasting for recording.

As always, submit burning questions at askdruniverse.wsu.edu. Who knows where your questions will take us next.

[Dr. Universe] Welcome back, young scientists. I’m Dr. Universe, and if you’re anything like me, you’ve got lots of big questions about our world.

Today we’re joining some amazing 4th grade scientists from Palouse Prairie Charter School. They’ve been working hard at Astronaut Academy and are ready to take us on a space tour.

Let’s get started.

[Ms. Savanna] Mission Control to Space Cadet Sophie and Dr. Universe: The 4th grade Crew at Palouse Prairie Charter School have completed intensive training at Astronaut Academy in preparation to set off on their Space Expedition and Exploration. We at mission control would like to send you to interview each crewmate in space before their return home. Your high speed space shuttle, the Boomcrusher, has been prepared by Mission Control Personnel and is ready for takeoff.

Safe travels through space.

[Sophie]: Dr. Universe, does that mean what I think it means?!

[Dr. Universe]: Buckle up, Sophie. We’re taking off!

[Dr. Universe]: Alright, Sophie, based on your space map, it looks like the first planet we set off to is the planet closest to the sun.

[Sophie]: That would be Mercury. I’ll plug it into our SPS, our Space Positioning System.

MERCURY

[Sophie]: Whoa, Dr. Universe, Mercury is traveling fast. Let’s see if we can catch up with Lorelai, Maddie, and Lily.

[Lorelai]: Hi, Dr. Universe! Hi, Sophie! You probably had a hard time catching up with us!

[Dr. Universe]: We sure did! How fast were you traveling?

[Maddie]: About 29 miles per second! Did you know that Mercury is the fastest traveling planet? That means Mercury goes all the way around the sun in just 88 Earth days. So, a year on Mercury equals 88 Earth days, and one day on Mercury equals about 59 Earth days.

[Lily]: Wait, that means If you lived on Mercury, you would have a birthday every three months!?

[Maddie]: That's correct.

[Lorelai]: Dr. Universe, did you know that Mercury goes through phases just like Earth’s moon? The phases of Mercury have a cycle that lasts around 116 Earth days, and they are determined by the planet’s position relative to the Earth.

[Lily]: As Mercury passes between our planet and the sun, the side facing the surface of Earth is not illuminated, so it’s completely dark like the moon during its new moon phases.

[Sophie]: Cool ice house. How did you build that!?

[Lily]: It’s funny you ask that, Sophie. When we arrived, we discovered that the surface of Mercury is scorching hot during the day. It’s about 800 degrees Fahrenheit by day. But at night, the temperature drops to around -290 degrees. Mercury’s axis is sheltered from the sun, which creates ice craters at the North and South Pole. The cold space air keeps the water frozen which helps keep us nice and cool during our exploration.

[Dr. Universe]: I have a question for you?

[Lorelai]: Ask away.

[Dr. Universe]: Is Mercury a terrestrial planet?

[Maddie]: Yes, Mercury is one of four terrestrial planets—meaning it has a solid crust made from magnesium, silicon, aluminum, and feldspar. Mercury is actually the smallest planet in our solar system. It’s only slightly larger than Earth’s moon. Not only is Mercury the smallest planet, it is also shrinking. Our planet’s size estimations say that Mercury is about 9 miles smaller than it was 4 billion years ago. It is believed that the iron core is cooling, making the core solid, and shrinking the planet.

[Dr. Universe]: Speaking of planets, Sophie and I need to hurry up and get to Venus.

[Maddie]: Oh, well it was nice talking to you.

[Sophie]: You, too.

[Mercury group]: Bye!

VENUS

[Eilya]: Welcome to Venus. We are Mission Venus 1. I am Eilya, and this is Celia and Sarah.

[Dr. Universe]: Finding Venus was tricky with all of that cloud cover. Are you expecting a storm?

[Celia]: Actually, Dr. Universe, we thought the same thing until we landed on Venus' surface. We noticed we had to travel through what seemed like 15 to 20 miles of a cloud cover. We learned that the atmosphere of Venus is made up mainly of carbon dioxide and thick clouds of sulfuric acid.

[Dr. Universe]: Thank goodness for such air tight spacesuits!

[Sarah]: No kidding. These clouds trap the natural heat of the planet, making Venus around 900 degrees Fahrenheit. That’s why Venus is hotter than Mercury. It also rains acid because sulfur dioxide reacts with water. The acid evaporates before it reaches the surface of Venus—but I think it is safe to say that no one can live on Venus.

[Dr. Universe]: Wow. What other discoveries have you made while on your space expedition?

[Eliya]: We found out that Venus spins clockwise, unlike the other planets. Venus spins on its axis from east to west while other planets typically spin from west to east. Venus orbits the opposite way of the sun, which is called retrograde rotation. This could explain why it takes 243 Earth days to orbit on the axis and 225 Earth days to orbit the sun.

[Sophie]: So, on Venus the sun rises in the west and sets in the east? Opposite of Earth? Why does Venus spin clockwise?

[Celia]: Astronomers have a few theories, Sophie. One theory is that the sun's strong gravitational pull on the dense atmosphere of Venus and friction between the core and mantle could have flipped the axis 180 degrees. That makes it seem as if the planet is upside down and spinning backwards. But astronomers aren’t quite sure yet.

[Dr. Universe]: Venus sounds so pretty and is such a nice name. Why did they name it Venus?

[Sarah]: Venus was named after the Roman goddess of love and beauty. It was most likely named “Venus” due to its bright, shining appearance in the sky. Venus is the only planet to be named after a female god and has always been considered a more feminine planet than the rest of them.

[Dr.Universe]: Wow. We learned so much about Venus today. It was a lot of fun being here, but now we are off to Mars!

[Everyone together]: Bye!

MARS

[Sophie]: Here comes Mars. Whoa. The sky is pink. My favorite color.

[Tristen]: Dr. Universe! Sophie! Just the people we wanted to see.

[Dr. Universe]: Well, hello. What are you working on?

[Gibson]: Well, when we were on our way to Mars, we encountered an asteroid that, luckily, we were able to avoid. We noticed a piece of our spaceship came loose after we escaped the doomsday rock. We had to eject and land on Mars. So now we’re salvaging parts off of a Mars rover to fix the wreckage.

[Dr. Universe]: Great use of supplies, crew!

[Tristen]: Thanks. In Astronaut Academy, we became experts on Mars rovers, so we know which parts are valuable to repair our ship.

[Sophie]: What’s that rover's name?

[Carson]: That’s Opportunity. Opportunity was only meant to last for 90 days on the surface of Mars. It lasted over 13 years before a huge dust storm rolled in. After the storm passed, Opportunity didn’t wake up.

[Gibson]: In 2012, Curiosity rover discovered evidence of water on Mars. At this time, it cannot support life, but if temperatures changed and lakes were created, it could sustain some life.

[Tristen]: NASA then launched Perseverance on July 30, 2020 and landed on the surface of mars on February 18, 2021. Perseverance rover is 10 feet long. One of its jobs is to collect rock samples.

[Carson]: Rovers have made so many discoveries on Mars. Pathfinder was the first rover on Mars in 1997 and may have discovered the truth behind why Mars is called the red planet. Pathfinder discovered that Mars is a dusty, cold, desert-like planet with a very thin atmosphere.

[Tristen]: This rover discovered that airborne dust is magnetic and a form of iron oxide. We have iron oxide on Earth, too. It’s called rust. Since iron oxide is red, Mars is nicknamed the red planet. This is also why the sky appears to be pink, Sophie.

[Gibson]: Rovers aren’t the only ones who have made amazing discoveries. Orbiters are orbiting Mars as we speak, and they have discovered amazing things, such as the gravity on Mars is much weaker than the gravity on earth. It's weak enough that you could jump three times higher on Mars than you could on Earth.

[Carson]: This also affects your weight. A cat that weighs 10 pounds on Earth would weigh less than 4 pounds on Mars.

JUPITER

[Kennedy]: Welcome, Dr. Universe. Did you know that Jupiter is named after the Roman Sky-god Jupiter? He was known to the Greeks as Zeus!

[Jason]: We have been exploring the 5th planet in the solar system from a safe distance. Jupiter has no solid surface. Instead, it has fuzzy cloud tops. The temperature there varies a lot. It can be freezing cold at the clouds tops and then boiling hot just 120 miles below the cloud tops.

[Dr. Universe]: How does the size of Jupiter compare to the size of Earth?

[Kennedy]: Jupiter is the largest planet in our solar system. About 1,300 Earths could fit inside it.

[Dr. Universe]: How many moons does Jupiter have?

[Jason]: Jupiter has 80 moons. The first 4 moons of Jupiter are called Galilean moons. They are named after the astronomer, physicist, and engineer Galileo.

[Dr. Universe]: What is Jupiter’s atmosphere made of?

[Jason]: Jupiter is a gas giant. Jupiter’s atmosphere is extremely dense and relatively dry. A mixture of hydrogen, helium, methane and ammonia makes up Jupiter’s atmosphere.

[Jason]: Did you know that this mixture of elements is also what made the sun?

[Dr. Universe]: How far is Jupiter to Earth?

[Kennedy]: It is 497.74 million miles.

[Dr. Universe]: Wow. You’re sure learning a lot about Jupiter. I’ll let you get back to it.

[Jason and Kennedy]: Ok, bye. See you later.

SATURN

[Dr. Universe]: Look, Sophie, there are our friends on Saturn.

[Sophie]: What are you guys doing all the way up here?

[Arrow]: We’re observing this gas giant from a distance. Saturn is a gas planet, meaning you cannot walk on it. If you attempt to land, you will sink into the planet's atmosphere a little. Then you will be vaporized.

[Sophie]: So you’re hovering around Saturn just to be safe?

[Ethan]: Right! We’ve discovered that Saturn's atmosphere is mostly made of hydrogen and helium, meaning there is no oxygen on Saturn to sustain life. Our detectors also found traces of ammonia, methane, and propane.

[Dr. Universe]: Wow. Those rings sure are remarkable. What are they made from?

[Arayna]: Saturn's rings are thought to be pieces of comets, asteroids or shattered moons that broke up before they reached the planet, torn apart by Saturn's powerful gravity.

[Sophie]: It looks like there are many rings. How many are there?

[Arayna]: Seven!

[Chase]: Saturn's biggest ring is the E-ring, which is 1,000,000 kilometers wide.

[Dr. Universe]: How big is Saturn?

[Chase]: Saturn is the 2nd largest planet in the solar system. About nine Earths side by side would almost span Saturn’s diameter. That doesn’t include Saturn’s rings.

[Dr. Universe]: Wow. That's amazing. I heard that there are gems on Saturn. Is that true?

[Ethan]: Scientists think it might rain diamonds on Saturn. They think lightning may turn methane into carbon soot. Then, that carbon hardens into diamond as it falls. It’s just an idea—but it’s a real gem!

[Dr. Universe]: Whoa, that's so cool. I also heard Saturn has many moons. How many does it have again?

[Arayna]: Saturn has 83 moons. 20 of them are unnamed and unresearched.

[Arrow]: I heard you have to study Uranus now, so you better be on your way.

URANUS

[Sophie]: It’s starting to get really cold!

[Dr. Universe]: I bet we’re getting close to the Ice giant Uranus.

[Sophie]: Micah! Nathan! Hi! I feel a draft coming from your planet.

[Nathan]: Sophie! You’re right. Uranus gets very cold. In fact, Uranus holds the record for the coldest temperature ever measured in our solar system: -435.2 degrees Fahrenheit. The atmosphere even contains ice. If you spill water on Uranus, it will freeze instantly. So no drinking water on–- Well, you can drink water on Uranus. You just have to drink in an isolated place that is heated.

[Micah]: Hey, do you two want to see a cool discovery we made? Look over there in the distance.

[Dr. Universe]: Those are rings!

[Micah]: They are! There was a great debate at Astronaut Academy on whether or not Uranus had rings. We can confirm that Uranus does have rings. There are 13 confirmed rings made of chunks of ice and rocks. You can’t see the rings from a telescope though because they don’t reflect infrared light.

[Dr. Universe]: Interesting. I also notice Uranus is spinning clockwise like Venus. What’s the scoop on that?

[Micah]: Based on a class I took at Astronaut Academy, scientists think that Uranus collided with an object the size of planet Earth about a billion years ago, and the impact was so great that it knocked this planet sideways.

[Dr Universe]: I sure am glad I wasn’t there for that! I have one last question before we head to Neptune. How did the planet Uranus get its name?

[Nathan]: This planet was named after the Greek god Uranus, known as the god of the sky and Zeus’ grandpa.

[Micah]: See you two later. I hope you don't get too dizzy on Neptune!

[Dr. Universe]: Ok. Bye for now!

[Sophie]: What did he mean by dizzy?

[Dr. Universe]: I guess we’ll soon find out!

NEPTUNE

[Becket]: Neptune has seasons just like Earth. Neptune's axis rotation is tilted 28 degrees, which is similar to the axial tilts of Mars and Earth. This means that Neptune experiences seasons just like we do on Earth. However, since its year is so long, each of the four seasons lasts for over 40 Earth years. And it stays cold all year—even in summer.

[Sophie]: What is an axis?

[Becket] : An axis is an invisible line through the middle of a planet, in which an object rotates or spins.

[Dr. Universe]: What major discoveries have you made?

[Finley]: We learned that Neptune has rings, and the rings glow in infrared light. The rings have lots of ice and dust in them that make a couple of them glow brightly. Neptune has five rings, two of them glow and three don’t. On July 12, 2022, the James Webb Space Telescope captured a clear image of Neptune’s rings glowing bright.

[Dr. Universe]: Is it raining diamonds?

[Saoirse]: Yes. They’re created from commonly found mixtures of hydrogen and carbon squeezed together at incredible pressures. Oceans of liquid diamond filled with solid diamond icebergs could be floating on Neptune right now.

[Saoirse]: Oh and one more thing: Something strange has happened to the temperature of Neptune that has left scientists scratching their heads.

[Finley]: The enormous ice planet known for its deep blue color had its temperature tracked for 17 years. Researchers have discovered that the temperature has been rising and falling with a period of cooling followed by a dramatic warming of its south pole.

[Becket]: The temperature dropped about 16 degrees Fahrenheit in the years 2003 to 2018. Then the temperature in the south pole rose about 22 degrees Fahrenheit from 2018 to 2020. Scientists were surprised at these changes. Some could say it quite literally came out of the blue.

[All]: Bye from the planet of Neptune. Have fun on Pluto!

PLUTO

[Emmy]: Hi! You must be Dr. Universe.

[Marken]: Welcome to our spaceship, the Pluto Pup. We’ve been looking forward to your visit.

[Dr. Universe]: It’s nice to meet you. I’m so curious to learn more about the planet Pluto.

[Emmy]: Well, um, Pluto might not exactly be a planet.

[Sophie]: What do you mean? What makes a planet a planet?

[Emmy]: Scientists continue to discuss this as they learn more, but let us explain.

[Marken]: First, a planet must orbit a star. In this case, the sun. As you know, Pluto does meet this requirement.

[Elise]: Second, a planet must be big enough to have enough gravity so it can be formed into a sphere like a giant ball. As you can see, Pluto also meets this requirement.

[Emmy]: And third, every planet also must have enough gravity to clear everything in its environment.

[Marken]: And that’s why Pluto is actually called a dwarf planet. Because it hasn’t actually cleared its surroundings of other objects. It still has asteroids and rocks traveling in its path.

[Sophie]: Wow! What’s that pink heart over there?

[Elise]: That’s Tombaugh Regio. The brightest feature on Pluto’s surface.

[Marken]: It’s a huge plain covered in frozen nitrogen. It’s icy—like a glacier!

[Emmy]: And it’s actually what makes it so windy on Pluto. Every day the thin layer of nitrogen evaporates into gas. And every night it freezes again. This cycle is like a heartbeat that pumps nitrogen winds all around our dwarf planet. Especially because it is a heart shape.

[Sophie]: Cool! I want to have my next birthday party on Tombaugh Regio.

[Emmy]: Ha! Here’s a fun fact: If you were from Pluto, celebrating your first birthday, do you know how old you would be on Earth?

[Marken]: You would be celebrating your 248th birthday!

[Sophie]: Ha! I mean my tenth EARTH birthday!

[Elise]: Besides, humans won’t be living here anytime soon. It’s way too cold! It’s usually around -278 degrees Fahrenheit here.

[Emmy]: You better get to Ivy to check her progress with supernovas.

[Dr. Universe]: Let’s get going, Sophie!

[Elise]: Safe travels!

SUPERNOVA

[Dr. Universe]: Before we head home, let’s zoom by a star that scientists expect to go supernova someday.

[Ivy]: Aren’t these colors remarkable? Sometimes changes happen in the center of a star. Those changes eventually cause the star to explode. That explosion is called a supernova.

[Dr. Universe]: Can scientists predict a supernova?

[Ivy]: Yes…and no. Astronomers can predict which stars might go supernova—but they don’t know when it might happen. The explosion takes the star by surprise.

[Ivy]: Astronomers believe the 10th brightest star in the sky, Betelgeuse, which is located in the Orion constellation, will be the next star to go supernova. Astronomers believe that if a star is giant and red, surrounded by a thick shroud of material, it will likely explode dramatically.

[Sophie]: That sounds scary!

[Ivy]: I agree. They can pose a major threat to galaxies and the planets within them, causing atmospheres to collapse, planets to be thrown out of orbit, and collisions with space hazards. The good news is for a supernova to affect Earth, it must be within 50 light years away— and Betelgeuse is about 642 light years away from Earth.

[Ivy]: Does this help explain what a supernova is?

[Sophie]: Yes and thank you.

[Dr.Universe] Bye, Ivy. See you back on Earth!

[Ivy] Bye.

[Dr. Universe] That's all for this episode, friends. Big thanks to Savanna Kilborn and her class at Palouse Prairie Charter School for working so hard on this project. A million thank yous to my friend Dr. Michael Allen from Washington State University for fact checking the script and helping us make sure it's perfect. And thank you to Northwest Public Broadcasting for inviting the class into the studio and recording them. You're the best.

As always, if you've got a question tickling your brain, you can submit it at askdruniverse.wsu.edu. That's A S K D R U U N I V E R S E dot W S U dot E D U.

Who knows where your questions will take us next.

Source List

Aguilar, D. A. (2011). 13 Planets: The Latest View of the Solar System. Washington D.C.: National Geographic Children's Books.

Mercury

Surface composition - Mercury

Water Ice on Mercury | NASA

Mercury Explained: Facts, Questions, and History - RocketSTEM

Venus

Venus | NASA

Space News

Overview | Venus – NASA Solar System Exploration

Apr 30th: Why Do Venus and Uranus Spin The Wrong Way? | 365 Days of Astronomy

Why Are Venus And Uranus Spinning in The Wrong Direction? : ScienceAlert