Roaming the Cosmos – Haumea

Astrophysicists currently surveying the outer edges of our solar system estimate that there are thousands of dwarf planets, though only five have been researched enough to be recognized officially by the International Astronomical Union: Ceres, Pluto, Haumea, Makemake, and Eris.

Ceres is the only dwarf planet in the inner solar system. It’s a part of the asteroid belt. Indeed, about one-third of the mass in the entire asteroid belt is concentrated in Ceres. The distant Eris is the most massive of all identified dwarf planets. It’s followed closely by Pluto and right behind is Makemake.

But the strangest by far is Haumea.

Located just past Pluto – Pluto’s distance from the sun averages about 3.7 billion miles and Haumea’s average is about 4 billion miles out – Haumea’s most obvious oddity is its shape. Rather than being spherical like most planets and planetoids, Haumea is a super-elongated ellipsoid that’s almost twice as long as it is wide. And this football-shaped dwarf planet is spinning wildly. Haumea has the fastest rotational speed of any large object in the solar system. In fact, it’s spinning as fast as physically possible. If Haumea were spinning any faster, it would tear in half under its own rotational energy.

We’ve previously explored places with high rotational speed. But if you were standing on a small asteroid, it would be apparent that it was the object that you were standing on that was spinning. But on Earth you do not feel as if you are spinning, even though the Earth is rotating at 1040 miles per hour at the equator. The sun and moon appear to move. The stars pass overhead. Yet you feel as if you are stationary while the universe turns above. The feeling would be the same on Haumea, only the universe would be turning much, much faster. Haumea completes a full rotation in just under four hours.

The brightest spots in this ever-moving sky would be the distant, distant sun and Haumea’s two moons. Haumea is named for the Hawai’ian goddess of childbirth and its moons are named for her daughters Namaka and Hi’iaka. According to IAU naming requirements, classical Kuiper Belt objects (the ring of icy planetoids outside of Neptune’s orbit) are named for deities associated with creation, but the usage of Hawai’ian gods is especially appropriate, given how important Hawai’i has been in exploring the universe. The Keck and Gemini telescopes at the Mauna Kea Observatory discovered both of Haumea’s moons and determined the dwarf planet’s surface composition… its strange, strange surface composition.

The bulk of Haumea is rock, but its surface is covered in a crystalline water ice features. Seeing the stars warp as their light passes through the massive ice features would be amazing. It’s also amazing because these features shouldn’t exist.

Haumea is located so far out in the solar system that crystal ice shouldn’t be able to form. Its surface temperature is below negative 370 degrees (F). At such an extremely low temperature water freezes so fast that the molecules don’t have time to arrange into crystals, instead creating amorphous ice. In addition, due to constant bombardment from cosmic rays, any crystal ice that did form should have reverted to amorphous ice over the course of about ten million years. But based on its position in the solar system, Haumea had to have formed over a hundred million years ago.

Crystal ice can be carried from underground to the surface by cryovolcanic processes, but Haumea’s surface doesn’t have any of the compounds that are associated with cryovolcanism, such as ammonia hydrate.

So far, no plausible resurfacing mechanism has been proposed. We just don’t know. How this strange and wonderful place at the edge of our solar system came to be is a story yet to be told.

Sources/Additional Reading:

Haumea –

Haumea: The Strangest Known Object in the Kupier Belt – California Institute of Technology

Dwarf Planet Named After Hawai’ian GoddessHawai’i Magazine

Haumea: Dwarf Planet and Hawai’ian Goddess – Love Big Island

From Hawaii’s Mauna Kea, a Universe of DiscoveriesThe New York Times

The Youthful Appearance of the 2003 EL61 Collisional FamilyThe Astronomical Journal

Strange Dwarf Planet Has Red Spot –