I find the outer reaches of our solar system fascinating. It鈥檚 a place that we know very little about considering how relatively close it is 鈥� even its size is up for debate. It鈥檚 littered with icy rocks, most of which are detectable only by huge telescopes. But soon we will have a chance to spot one of these strange worlds.
Pluto is undoubtedly the most famous of all the dwarf planets, because it was once considered part of the main lineup of planets in our solar system. But there are four other dwarf planets officially recognised by the International Astronomical Union. Unlike the planets, most of which are easy to spot with the naked eye, finding the dwarf planets is tricky to do and requires a telescope.
Perhaps the strangest of them all, Haumea, is at opposition on 22 April. This means it is on the same side of the sun as Earth. In other words, Earth sits perfectly in between the sun and Haumea, making it the ideal time to look for it in the night sky as its rocky body reflects sunlight back at us.
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The egg-shaped dwarf planet, also known as 2003 EL61, was the first of its kind to be found since Pluto was discovered in 1930. Its discovery sparked controversy, as two teams of astronomers claimed to have found it 鈥� one that first spotted it in 2003 and another that first announced it in 2005. It took a few more years before the tiny world was named Haumea, after the Hawaiian goddess of fertility.
Haumea is a curious rock. At about one-seventh the size of Earth, with an equatorial diameter of around 1700 kilometres, it is roughly the same size as Pluto. But it is one of the fastest-spinning large objects in the solar system, rotating every 4 hours, and it takes 285 years to orbit the sun from its location far beyond Neptune in an icy region called the Kuiper belt. It has two known moons and a ring that was discovered in 2017, making it the first known Kuiper belt object to have any rings.
Finding Haumea isn鈥檛 easy. The best time to look is around 22 April, when its opposition coincides with its closest approach to Earth, so it will be at its brightest. You will need a telescope with an aperture of at least 25 centimetres, and even then it will look like a point of light. Long-exposure astrophotography is the only way to make out its oval shape, shown in the illustration above.
It will be near the bright star Arcturus, in the constellation Bo枚tes, reaching the highest point in the sky around midnight from anywhere in the world. Viewers in the northern hemisphere, like me, will be able to see it all night; from the southern hemisphere, it will be visible most of the night.
I first glimpsed Haumea a few years ago. Although it just looks like a speck of light, I found it really exciting to look at, knowing it is part of our own solar system. It felt more familiar, somehow, than the distant stars or galaxies I鈥檓 used to finding with my telescope.
What you need
A telescope with an aperture of at least 25 centimetres
Abigail Beall is a features editor at New Scientist and author of The Art of Urban Astronomy. Follow her @abbybeall
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