10 Facts About the Dwarf Planet Haumea

Kevin Gill, Flickr // CC BY-2.0
Kevin Gill, Flickr // CC BY-2.0

In terms of sheer weirdness, few objects in the solar system can compete with the dwarf planet Haumea. It has a strange shape, unusual brightness, two moons, and a wild rotation. Its unique features, however, can tell astronomers a lot about the formation of the solar system and the chaotic early years that characterized it. Here are a few things you need to know about Haumea, the tiny world beyond Neptune.

1. THREE HAUMEAS COULD FIT SIDE BY SIDE IN EARTH.

Haumea is a trans-Neptunian object; its orbit, in other words, is beyond that of the farthest ice giant in the solar system. Its discovery was reported to the International Astronomical Union in 2005, and its status as a dwarf planet—the fifth, after Ceres, Eris, Makemake, and Pluto—was made official three years later. Dwarf planets have the mass of a planet and have achieved hydrostatic equilibrium (i.e., they're round), but have not "cleared their neighborhoods" (meaning their gravity is not dominant in their orbit). Haumea is notable for the large amount of water ice on its surface, and for its size: Only Pluto and Eris are larger in the trans-Neptunian region, and Pluto only slightly, with a 1475-mile diameter versus Haumea's 1442-mile diameter. That means three Haumeas could fit sit by side in Earth—and yet it only has 1/1400th of the mass of our planet.

2. HAUMEA'S DISCOVERY WAS CONTROVERSIAL.

There is some disagreement over who discovered Haumea. A team of astronomers at the Sierra Nevada Observatory in Spain first reported its discovery to the Minor Planet Center of the International Astronomical Union on July 27, 2005. A team led by Mike Brown from the Palomar Observatory in California had discovered the object earlier, but had not reported their results, waiting to develop the science and present it at a conference. They later discovered that their files had been accessed by the Spanish team the night before the announcement was made. The Spanish team says that, yes, they did run across those files, having found them in a Google search before making their report to the Minor Planet Center, but that it was happenstance—the result of due diligence to make sure the object had never been reported. In the end, the IAU gave credit for the discovery to the Spanish team—but used the name proposed by the Caltech team.

3. IT'S NAMED FOR A HAWAIIAN GODDESS.

In Hawaiian mythology, Haumea is the goddess of fertility and childbirth. The name was proposed by the astronomers at Caltech to honor the place where Haumea's moon was discovered: the Keck Observatory on Mauna Kea, Hawaii. Its moons—Hi'iaka and Namaka—are named for two of Haumea's children.

4. HAUMEA HAS RINGS—AND THAT'S STRANGE.

Haumea is the farthest known object in the solar system to possess a ring system. This discovery was recently published in the journal Nature. But why does it have rings? And how? "It is not entirely clear to us yet," says lead author Jose-Luis Ortiz, a researcher at the Institute of Astrophysics of Andalusia and leader of the Spanish team of astronomers who discovered Haumea.

5. HAUMEA'S SURFACE IS EXTREMELY BRIGHT.

In addition to being extremely fast, oddly shaped, and ringed, Haumea is very bright. This brightness is a result of the dwarf planet's composition. On the inside, it's rocky. On the outside, it is covered by a thin film of crystalline water ice [PDF]—the same kind of ice that's in your freezer. That gives Haumea a high albedo, or reflectiveness. It's about as bright as a snow-covered frozen lake on a sunny day.

6. HAUMEA HAS ONE OF THE SHORTEST DAYS IN THE ENTIRE SOLAR SYSTEM.

If you lived to be a year old on Haumea, you would be 284 years old back on Earth. And if you think a Haumean year is unusual, that's nothing next to the length of a Haumean day. It takes 3.9 hours for Haumea to make a full rotation, which means it has by far the fastest spin, and thus shortest day, of any object in the solar system larger than 62 miles.

7. HAUMEA'S HIGH SPEED SQUISHES IT INTO A SHAPE LIKE A RUGBY BALL.

haumea rotation gif
Stephanie Hoover, Wikipedia // Public Domain

As a result of this tornadic rotation, Haumea has an odd shape; its speed compresses it so much that rather than taking a spherical, soccer ball shape, it is flattened and elongated into looking something like a rugby ball.

8. HIGH-SPEED COLLISIONS MAY EXPLAIN HAUMEA'S TWO MOONS.

Ortiz says there are several mechanisms that can have led to rings around the dwarf planet: "One of our favorite scenarios has to do with collisions on Haumea, which can release material from the surface and send it to orbit." Part of the material that remains closer to Haumea can form a ring, and material further away can help form moons. "Because Haumea spins so quickly," Ortiz adds, "it is also possible that material is shed from the surface due to the centrifugal force, or maybe small collisions can trigger ejections of mass. This can also give rise to a ring and moons."

9. ONE MOON HAS WATER ICE—JUST LIKE HAUMEA.

Ortiz says that while the rings haven't transformed scientists' understanding of Haumea, they have clarified the orbit of its largest moon, Hi'iaka—it is equatorial, meaning it circles around Haumea's equator. Hi'iaka is notable for the crystalline water ice on its surface, similar to that on its parent body.

10. TRYING TO SEE HAUMEA FROM EARTH IS LIKE TRYING TO LOOK AT A COIN MORE THAN 100 MILES AWAY.

It's not easy to study Haumea. The dwarf planet, and other objects at that distance from the Sun, are indiscernible to all but the largest telescopes. One technique used by astronomers to study such objects is called "stellar occultation," in which the object is observed as it crosses in front of a star, causing the star to temporarily dim. (This is how exoplanets—those planets orbiting other stars—are also often located and studied.) This technique doesn't always work for objects beyond the orbit of Neptune, however; astronomers must know the objects' orbits and the position of the would-be eclipsed stars to astounding levels of accuracy, which is not always the case. Moreover, Ortiz says, their sizes are oftentimes very small, "comparable to the size of a small coin viewed at a distance of a couple hundred kilometers."

New British Coin Featuring a Black Hole Honors Stephen Hawking

The Royal Mint
The Royal Mint

It has been one year since Stephen Hawking’s death, but the theoretical physicist’s life and legacy live on in both time and space. In an effort to immortalize the late scientist, Hawking’s words were beamed toward the nearest black hole last June, and now, he has his very own coin in the UK.

As New Scientist reports, The Royal Mint has created a 50-pence coin featuring a drawing representing a black hole, Stephen Hawking’s name, and an equation he co-created with Jacob Bekenstein to describe the entropy of a black hole. Though Hawking wasn't the first scientist to predict the existence of black holes, he devised mathematical theorems (like the one on the coin) that lent credence to their existence in the universe. He was also the first person to discover that black holes weren’t entirely black because they emit radiation, and are therefore capable of evaporating and disappearing.

Edwina Ellis, who designed the collector's coin, said she was inspired by a lecture Hawking gave in Chile in 2008. “Hawking, at his playful best, invites the audience to contemplate peering into a black hole before diving in,” Ellis said in a statement. “I wanted to fit a big black hole on the tiny coin and wish he was still here chortling at the thought.”

A different Stephen Hawking coin
The Royal Mint

The Royal Mint says the Hawking coin is the first in a new series that celebrates British innovation in science. The coins come in gold proof, silver proof, silver proof piedfort, and “brilliant uncirculated,” and they’re being sold on The Royal Mint’s website (although most are currently sold out). In recent years, UK coins have also commemorated Sir Isaac Newton and Charles Darwin.

[h/t New Scientist]

First Person on Mars Will Likely be a Woman, Says NASA Boss

NASA astronaut Nicole Aunapu Mann at an event in August 2018
NASA astronaut Nicole Aunapu Mann at an event in August 2018
Bill Ingalls, NASA via Getty Images

In what is sure to be one giant leap for humankind, the head of NASA has announced that the first astronaut to set foot on Mars is “likely to be” female. As CNN reports, NASA administrator Jim Bridenstine made the comment while appearing as a guest on a recent episode of Science Friday, a science and technology radio show.

At one point in the conversation, Bridenstine fielded a question from Grab Your Wallet Alliance co-founder Shannon Coulter, who asked in a tweet whether a woman would be involved in the next Moon landing, which could occur in 2028, if NASA gets its wish.

“The answer is absolutely,” Bridenstine answered. “In fact, it’s likely to be a woman—the first next person on the Moon. It’s also true that the first person on Mars is likely to be a woman.”

It is too early to tell which female astronauts might be eligible for the Mars mission, which is tentatively scheduled for the 2030s. However, Bridenstine said the space agency is committed to having a “broad and diverse set of talent.” Currently, 34 percent of active NASA astronauts are women. While the gender gap has not yet been closed, it’s still a significant change from 1978, when six women (including Sally Ride) became the first American female astronauts. In addition, women comprised half of the 2013 astronaut class and five of 12 astronauts in the 2017 class, as well as half of the most recent class of flight directors.

The first all-female spacewalk will take place on March 29, rounding out National Women’s History Month. Astronauts Anne McClain and Christina Koch will be assisted by flight directors Mary Lawrence and Kristen Facciol on the ground during the roughly seven-hour spacewalk. These events typically involve making repairs to the International Space Station—a job that has traditionally been undertaken by men.

[h/t CNN]

SECTIONS

arrow
LIVE SMARTER