This article was originally published on The Conversation. The book donated the article to Space.com Soundtracks: Op-Ed & Insights.
Peroomian divisionProfessor of Physics and Astronomy, USC Dornsife College of Letters, Arts and Sciences
“What is a dwarf world?” – Myranda, age 8, Knoxville, Tennessee
The word “planet” comes from an ancient Greek word meaning “wandering star.” That’s good, because for thousands of years, people have watched the stars change position in the night sky – unlike the stars, which are visible and invisible to the naked eye.
That is why the ancients saw five of the stars: Mercury, Venus, Mars, Jupiter and Saturn. Astronomers using telescopes have found Uranus in 1781, Neptune in 1846, and Pluto in 1930.
The remnants of the solar system
I am an aerospace scientist with a passion for astronomy and exploration of the solar system. I got my Ph.D. in physics in 1994, about the time astronomers began to see more than Neptune, in the Kuiper belt. It’s a place in space where the “leftovers” of the solar system are held – mostly small ice bodies.
Three of those ice bodies – Eris, Haumea and Makemake – were seen in the early 2000s. They seem to be enough to become hotels; They are all about the same size as Pluto.
Astronomers think there may be more of these ice bodies in the Kuiper belt. They began to wonder: How many stars can we see in our solar system? twenty? Thirty? A hundred? Better?
The dwarf world is described
In 2006, and after much debate, the International Astronomical Union came out with a new definition of the earth. And for the first time, the term “dwarf planet” was used.
Here is what the IAU says: The earth must revolve directly around the sun. Many also need to have a round, round, body shape.
And the world needs to “clean up its community.” That is, apart from the moons it has, the Earth cannot share its orbit with different objects.
An object that fulfilled only the first two levels – but not the last – is now called a dwarf world.
Pluto is reduced
That is why Pluto lost its status as a planet and is now considered a dwarf planet. The last thing dropped on the list – Kuiper belt bodies are in its orbital path. The conclusion, which is a matter of fact, has been debated by scientists to this day.
At the same time that Pluto was lowered, a solar system was introduced. Ceres, now considered an asteroid, is considered a dwarf planet. Nowhere near the Kuiper belt; however, Ceres is in the large asteroid belt, orbiting between Mars and Jupiter.
Combine them – Pluto, Ceres, Eris, Haumea and Makemake – and that will increase the number of small baskets of our solar system to five. But that list is growing. Now, hundreds of candidates, almost all in the Kuiper belt, can meet the requirements to become a dwarf world.
About dwarf cages
There is no such thing as Earth.
As their name suggests, it’s much smaller. Pluto and Eris, the largest of the dwarves, make up about one -fifth of Earth’s diameter.
Their mass is less. For example, the Earth is about 6,400 times larger than Ceres. It’s like comparing two killer whales to a guinea pig.
And the dwarf stars are cold. Pluto’s average temperature is about 400 degrees Fahrenheit (less than 240 Celsius).
Is it possible to survive in a dwarf world?
There are three essential elements for life: water, an energy source and organic molecules – that is, the molecules that contain carbon.
More than 100 miles (161 kilometers) below the surface of Pluto is an ocean of water; This may be true for other Kuiper belt clouds. Ceres has water under the earth, a remnant of the ancient Earth’s oceans.
Organic molecules are found, in all parts of our solar system, on Ceres and Pluto.
But what is lost for all dwarf cages is a source of energy.
The sun doesn’t go down, the Kuiper belts are more crowded; they are far from the sun. To reach the belt, light must travel more than 2.7 billion miles (4.4 billion km). When the sun comes to these distant worlds, none of them can be too hot.
And all the small baskets are too small to store the remaining internal heat from the launch of the solar system.
However, scientists have seen life on Earth in the worst places imaginable – close to the bottom of the ocean, miles deep in the ground and in a powerful volcano. When it comes to life in our solar system, don’t say no.
This article is republished The Conversation under the Creative Commons license. Read to Original article.
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