10 Facts About the Dwarf Planet Eris

An artist's rendering of the dwarf planet Eris
An artist's rendering of the dwarf planet Eris
ESO/L. Calçada and Nick Risinger (skysurvey.org) // CC BY 4.0

Far beyond the orbit of Pluto exists a celestial body that’s a little smaller, a little colder, and a little denser—the dwarf planet Eris. In Greek mythology, Eris is the goddess of strife, and never was there a more appropriately named body in the solar system. When astronomer Mike Brown of Caltech and his team discovered Eris in 2005, the finding set off a chain reaction that would see the planetary status of Pluto called into question. Here are 10 things you might not know about Eris.

1. An Eridian day is just slightly longer than Earth's.

If you were an astronaut, you wouldn’t find an Eridian day, at 25.9 hours, too disconcerting. This compares favorably with, say, Venus, whose day lasts 5832 hours (admittedly, it's an outlier). An Eridian year is a bit longer than what we're used to, with the dwarf planet completing an orbit of the Sun every 557 Earth years. And that orbit is not along the relatively flat plane with the orbits of most of the other planets of the solar system. Imagine your elementary school solar system model of planets on wires around a light bulb: Instead of a path neatly aligned with the other planets, Eris’s orbit is tilted at a 44 degree angle.

2. Eris was once thought to be bigger than Pluto.

After Eris’s discovery, the best measurements then available placed it as slightly larger than Pluto, with a radius of 722 miles. But after the initial spacecraft reconnaissance of Pluto by New Horizons in 2015, Pluto’s ranking as the ninth-largest planetary object orbiting the Sun was restored; it is now known to have a radius of 736 miles. In comparison, Earth’s Moon has a radius of 1079 miles. Ganymede, Callisto, Io, and Europa (Jupiter’s largest moons), Titan (Saturn’s largest moon), and Triton (Neptune’s largest moon) are also bigger than Pluto. On the other hand, Eris is 34 percent denser than Pluto.

3. Eris is responsible for the big debate over the definition of "planet."

When Brown’s team discovered Eris, it was initially hailed as either the 10th planet of the solar system, or a big problem for scientists who like nicely ordered celestial objects. The discovery of Eris came on the heels of the discoveries of Sedna and Quaoar, both beyond the orbit of Neptune. Astronomers were looking at the possibility of a dozen planets in the solar system or more, because—based on these three—who knew how many Pluto-sized bodies were out there? The International Astronomical Union eventually defined a planet in our solar system as something that has achieved hydrostatic equilibrium (in other words, it's round), orbits the Sun, and has “cleared its neighborhood” (i.e., is gravitationally dominant in its orbit). Yet the debate continues [PDF].

4. It has its own moon.

Eris has a moon called Dysnomia that circles the dwarf planet every 16 days. In Greek mythology, Dysnomia is the name of one of Eris’s daughters and means “anarchy.”

5. Initially, Eris was called Xena.

Before it was called Eris, it was called 2003 UB313 (a provisional designation by the International Astronomical Union). But before that, Brown’s team of astronomers named it Xena—yes, of Warrior Princess fame. “We always wanted to name something Xena,” Brown told The New York Times in 2005 after the discovery. Among Brown’s colleagues, Dysnomia was called Gabrielle, who was, of course, Xena’s sidekick.

6. Its surface is like Pluto's heart.

The primary way to analyze the composition of the surface of a celestial body is through spectroscopy, which is basically looking at an object and seeing how much light comes back at you as a function of wavelength. Many materials have characteristic absorptions of light at certain frequencies, and so less light will come back to you at that frequency.

“Eris has very, very strong methane ice absorption bands,” Will Grundy, a planetary scientist at Lowell Observatory and a member of the New Horizons team, tells Mental Floss. “They are much stronger than Pluto’s, and of course we’ve seen methane all over the place on Pluto, so I think it’ll be more ubiquitous on Eris’s surface.” The implication is that Eris is more than just a dead ice rock in space, because methane degrades very quickly in a space environment, darkening and forming heavier hydrocarbons. “The fact that it’s bright and covered with methane ice says it’s refreshing its surface relatively rapidly, and there are any number of ways it can do that. One is the methane just periodically sublimates underneath the atmosphere and then re-condenses somewhere else, just sort of painting on top of whatever dark stuff that forms,” Grundy says.

7. Pluto data enriches our understanding of Eris.

Pluto data returned from the New Horizons spacecraft give scientists new ideas about the processes that might be at work on Eris. “One of the things the Pluto flyby showed us that nobody really talked about, even in wild speculations, was something like Sputnik Planitia: this big, bright, teardrop-shaped region on the encounter hemisphere. Volatile ices there are trapped in a deep basin and they are just convectively overturning, like a simmering pot of soup,” Grundy says.

That process might be happening writ large on Eris. It might be, in a sense, an ice lava lamp planet. “I’ve called it a Sputnik planet,” Grundy says, “but nature is much more clever than scientists at coming up with new ways of doing things with the same old ingredients. Who knows, we might get there and find out it’s doing something completely different than Pluto was doing to refresh its surface. The real lesson is that activity on a lot of different timescales is possible, even on a tiny little planet that’s at frigid temperatures, far away from the sun.”

8. Its neighborhood is a potential gold mine of information.

In comparative planetology, scientists use planets to understand other planets. By studying Venus, which is similar to Earth in terms of size, mass, and basic composition, scientists can better understand how our planet operates and evolved. The objects in Eris’s celestial neighborhood work the same way. “The Kuiper Belt”—a region rich in rocky and icy objects beyond Neptune’s orbit—“is an incredibly rich environment for comparative planetology because there are so just many of these tiny planets out there,” Grundy says. “It’s going to take a while to discover them all, let alone explore them all, but that’s what is exciting about it.” The New Horizons data from Pluto are helping planetary scientists develop models to tease out the secrets of Eris.

9. Geologists could learn a lot, too.

“If you work out the surface area of, say, objects there that are bigger than 100 kilometers, based on extrapolation, the Kuiper Belt has more solid geology surface area than of all of the planets in the solar system—including the terrestrial planets—combined,” Grundy explains, adding that it holds true even if you wanted to include the ocean floor on Earth. “If you like geology—and especially if you like exotic, cryogenic temperature geology—this is the place to explore, and there’s just so much territory to explore out there.”

10. A mission to Eris will take a while.

It took New Horizons, one of the fastest spacecrafts ever built, nine years to get to Pluto. Eris is currently three times farther from the Sun than Pluto (though due to a highly elliptical orbit, this number changes), so if a mission is ever approved, don’t expect to find out how it all ends. “It takes decades to pull something like that together, so if you want to be around to see the results, you’ve got to start young,” Grundy says. A possible future Kuiper Belt mission might be part of a flyby mission to Uranus or Neptune, after which the spacecraft would continue into that region of space. It will be a very long time before technology allows an Earth-centric telescope—in space or otherwise—to take pictures of the geology of Eris.

The Orionid Meteor Shower Will Peak on Monday Night

jk78/iStock via Getty Images
jk78/iStock via Getty Images

If you missed Halley's Comet's last trip through the inner solar system in 1986, you'll have to wait a while to catch its next appearance. The comet is only visible from Earth every 75 to 76 years. Though the comet itself is elusive, the debris from its tail lights up the night sky on a regular basis. To view the Orionid meteor shower when it peaks today—Monday, October 21, 2019—here's what you need to know.

What Are the Orionids?

As Halley's Comet propels through our solar system, it drags a trail of rocks and dust behind it. The tail is vast enough to a leave thick band of space debris in its wake. Every October, our planet passes through this rocky field, producing brilliant "shooting stars" as the meteors burn up in the atmosphere. From Earth, the meteor shower appears to originate from the constellation Orion, which is how it got its name.

When to See the Orionid Meteor Shower

The Orionids are visible from Earth starting in the beginning of October, but they don't peak until the latter half of the month. This year, the meteor shower will be brightest the night of Monday, October 21 and the morning of Tuesday, October 22. The moon will be around its last quarter phase at this time, which means that bright skies could wash out the light show for many. But if you wait until the hours leading up to dawn, when the moon sets and skies are darkest, you may be able to spot the shower.

To see it, make sure you're in an area with clear, open skies and minimal light pollution. Whether you live in the Northern or Southern hemispheres, you should be able to experience the phenomena if conditions are optimal.

[h/t Newsweek]

10 Out-of-This-World Facts About Space Camp

U.S. Department of Education, Flickr // CC BY 2.0
U.S. Department of Education, Flickr // CC BY 2.0

Each year, millions of kids fill their summer vacation days with songs, crafts, and outdoor activities at camp. Summer camps across the U.S. share many similarities, but Space Camp in Huntsville, Alabama is unique. Instead of canoeing and archery, young attendees get to ride spacecraft simulators, build robots, and program computers. It’s the closest young civilians can come to working for NASA.

Space Camp welcomed its first aspiring astronauts in 1982, and since then, more than 900,000 campers have attended the program. From its famous alumni to its depiction in film, here are some more facts about Space Camp.

1. The movie SpaceCamp boosted its popularity.

SpaceCamp, the movie inspired by the real camp in Huntsville, Alabama, wasn’t a huge hit when it debuted in theaters in 1986. It grossed just $9,697,739—a little more than half its reported budget. But it didn’t fade into obscurity completely. The film saw success in the home video market and became popular enough to leave a lasting mark on pop culture. Dr. Deborah Barnhart, the real camp’s director for part of the 1980s, told AL.com that attendance doubled following the movie’s release. SpaceCamp shot many of its scenes on location at the Huntsville center. The life-sized space-shuttle flight-deck and mid-deck built for the film were donated to the camp and used as a simulator there from 1986 to 2012.

2. Space Camp was the brainchild of a missile designer.

Some people may be surprised to learn that Space Camp is located in Alabama and not Florida, home to Cape Canaveral and the Kennedy Space Center (the movie SpaceCamp is set in Florida despite being filmed in Alabama). But Huntsville, Alabama, has been a major aeronautics center since the 1950s when Wernher von Braun and his team of rocketeers moved there. The German scientist had designed ballistic missiles for the United States military after World War II, and shortly after relocating to Huntsville, he redirected his attention to space flight. He launched the U.S. Space and Rocket Center as a way to demonstrate the area’s rocket technology to tourists. Von Braun also came up with the idea for a science-focused alternative to traditional summer camps after seeing children touring the rocket center and taking notes. Space Camp opened at the center in 1982, a few years after his death.

3. Space Camp activities go beyond space.

The kids at Space Camp do more than ride giant rocket simulators. After enrolling, young campers choose a track to focus on. They can study aviation and learn air navigation and combat techniques, choose robotics and build their own robots, or stick to space-centric subjects and activities. The newest Space Camp experience, cyber camp, teaches kids programming and online security skills.

4. The Space Camp simulators don’t make campers sick.

Space Camp is home to three simulators based on real-life training rigs astronauts use to prepare for space missions. The most intense rig is the multi-axis trainer, and just watching a video of it in action may be enough to make you feel queasy. But according to the camp’s website, campers “should not become sick or dizzy on any of our simulators.” On the multi-axis trainer, this is due to the fact that the rider's stomach remains at the center of the chair throughout the simulation, even as the chair itself is spinning in all directions. Motion sickness is caused when your inner ear fluid and your eyes send your brain conflicting information. Because the rig tumbles so wildly, the rider's inner fluid never has a chance to shift and make them want to vomit.

5. Space Camp boasts some famous alumni.

Space Camp attracts bright young minds from around the world, including a few celebrities. Chelsea Clinton attended the week-long program when her father was in the White House in 1993. Amy Carter, Jimmy Carter’s daughter, and Karenna Gore, daughter of Al Gore, also enrolled in the camp. But not every famous Space Camp graduate came from the world of politics: South African actress Charlize Theron is another notable alumna.

6. Several Space Camp graduates went on to be astronauts.

Many kids who go to Space Camp dream of growing up to be astronauts, and for some of them, that dream becomes a reality. The camp’s alumni includes the “Tremendous 12”—a handful of Space Camp graduates who’ve made it to space. Most members of this elite group were trained by NASA, but a few of them went on to work for other space agencies like the ESA.

7. Most Space Campers end up in STEM professions.

Space Camp in Huntsville, Alabama.
GPA Photo Archive, Flickr // CC BY-SA 2.0

Even if they don’t go on to be astronauts, most Space Camp attendees have bright futures ahead of them. According to the camp, 61 percent of graduates are studying aerospace, defense, energy, education, biotech, or technology, or they’re working in one of those fields already. Of the alumni pursuing careers in STEM, half of them said that Space Camp inspired that decision.

8. There’s a Space Camp for visually impaired kids.

The U.S. Space & Rocket Center in Huntsville, Alabama hosts a second Space Camp that shares a lot in common with its original program. There are space simulators, astronaut-training missions, and even scuba diving—the main difference is that the kids there are blind or visually impaired. Space Camp for Interested Visually Impaired Students, or SCIVIS, offers children in grades 4 to 12 a crash course in various STEM subjects. They use accessible tools, like computers adapted for speech and reading materials printed in braille or large print. Activities for the week-long camp are organized by teachers familiar with the needs of visually impaired students.

9. Double Dare sent winners to Space Camp.

After conquering the obstacle course of the Nickelodeon game show Double Dare, kid contestants were sent home with various prizes. Though no doubt exciting in the 1980s and '90s, many of the prizes—which included encyclopedias, cassette recorders, and AOL subscriptions—haven’t aged well. A trip to Space Camp was one of the biggest awards players could win, and it’s one of the few that would still have value today.

10. Adults can go to Space Camp too.

If you never went to Space Camp as a kid, you haven’t missed your chance. While the regular Space Camp is only open to kids ages 9 to 18, the U.S. Space & Rocket Center also offers camp programs for older space enthusiasts. Family Space Camp is designed for groups that include at least one child and one adult, and if you don’t plan on tagging along with a kid, you can enroll in the three-day Adult Space Camp experience that’s strictly for campers 18 and older.