Our solar system has five dwarf planets, including the dwarf planet previously known as a Pluto. One of the other dwarf planets in our solar system that many have probably never heard of is called Makemake. Scientists studied makemake for the first time in April 2011 as it passed between the Earth and a distant star.
Scientists studied the planet using seven different telescopes on Earth to see how the stars light changed as Makemake traveled in front of it. Using the telescopes here on Earth, the scientists were able to determine that the dwarf planet lacked an atmosphere and scientists were even able to determine the dwarf planet's density.
Scientists from the Andalucian Institute of Astrophysics in Spain studied Makemake using seven different telescopes located across Brazil and Chile. The astronomers watched the dwarf planet as it partially blocked the light from a distant star called Nomad 1181-0235723. Makemake blocked the stars light for only about 1 minute, but that was long enough to reveal a few details about the planet.
Scientists determined that the dwarf planet is about two-thirds the size of Pluto, but isn't quite spherical. The dwarf planet is 1430 km across in one direction and about 1500 km across and the other. The scientists also determined that the dwarf planet has a density of 1.7 g per cubic centimeter. The density makes it similar to Pluto, but less than a third the density of Earth.
"As Makemake passed in front of the star and blocked it out, the star disappeared and reappeared very abruptly, rather than fading and brightening gradually," said Dr Ortiz.
"This means that the little dwarf planet has no significant atmosphere. It was thought that Makemake had a good chance of having developed an atmosphere - that it has no sign of one at all shows just how much we have yet to learn about these mysterious bodies.
"Finding out about Makemake's properties for the first time is a big step forward in our study of the select club of icy dwarf planets."