Mysterious Dwarf Planet Haumea Might Have Been a Major

The rules for being a major planet are simple; it must orbit the sun, it must have enough gravitational pull to form a spherical shape, and it must clear its orbital path of major debris. That last rule is the one that knocked poor Pluto into the dwarf league.

Sad though Pluto’s plight may be, it is nothing compared to that of Haumea, discovered in 2003. Haumea orbits the sun in the Kuiper Belt, that vast field of planetary bits and pieces that lies beyond the orbit of Neptune.

Here Comes the Sun

Haumea is about as big as Pluto, but only on her longest side. She isn’t round, but football shaped – a tapered cylinder 1,200 miles tall. And she tumbles end-over-end, making a complete tumble about once every four hours. Standing at one of the poles you’d see the sun, from there a very bright star, rise from below and in front of you, soar overhead, and set below and behind you.


But where Pluto has the tiny moon Charon to keep it company, Haumea has both Hi’iaka and Namaka orbiting her. They are spherical either, but appear to be massive chunks of ice – space icebergs – that were torn off of Haumea, just as Charon is believed to have been torn out of Pluto, some time long, long ago.

Knocked out of the Majors


It is widely believed that Earth was smacked by a Mars-sized intruder back in our early formation days. The collision was so massive that the moon was torn right out of us. Before Haumea, we thought we and Pluto were the only collision survivors.

But an ancient collision is assumed to be the reason for both Haumea’s odd shape and her curious tumbling. The moons Hi’iaka and Namaka are very probably chunks of the dwarf planet.

If that collision hadn’t occurred, Haumea may very well have been spherical. And, since her orbital path is crowded with debris believed to have been ejected from the crash, it may have once been clear. That would classify her as a major planet! Ah, the cruel fates.

A Long, Long Tumble

Haumea is a rocky planet embedded in a sheath of ice. This is different from Pluto, which is believed to have a much higher ice content. Haumea’s end over end tumbling is probably what caused her to assume the elongated structure. That structure would have assumed an even more banana shape if not for her rocky core.

The collision is believed to have taken place roughly around the same time as our own: 4.5 billion years ago.

Picture this: that dwarf planet has been silently tumbling end-over-end, like a badly thrown football, for over four billion years.

You can learn more about Haumea’s amazing journey at Mike Brown’s Planets, a Cal Tech site.

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