This is what the solar system looked like for most of the 20th century.
“Even if it didn’t make sense from a scientific point of view, it would be nice if it did. The problem was, after discovering Eris and realizing Eris was more massive than Pluto, we had no choice but to do something. ”
The decision about this “something” was finally made by the International Astronomical Union in August 2006, after they decided to define what a planet is.
Although Mike Brown plays the role of the bad guy in this story, the truth is that he never had anything against Pluto … quite the contrary.
“I remember when I was little I had a poster on my wall with all the planets, their orbits, and even some asteroids. The artist imagined the surface of Pluto with its needles rising to the sky and so delicate that it seemed that if you touched it it would burst …
“How could I not be fascinated by such a distant, strange and delicate place? Pluto was one of my favorites as a child“.
The present dwarf planet was discovered in 1930 by the American astronomer Clyde Tombaugh.
Astronomers have been searching for it since the discovery of Neptune in 1846 by the French Urbain Le Verrier. Neptune and its neighbor Uranus were thought to be gravitationally pulled by “something big”, influencing the shape of their orbits.
“The American Percival Lowell, who called it” Planet X, “founded an entire observatory to look for it: Lowell Observatory in Flagstaff, Arizona.
Lowell died without finding him, but the observatory continued its search, looking at the area he had predicted the planet should exist in.
“In 1930, Tombaugh found the point where light moved. Movement meant it was part of the solar system; moving slowly meant it was very far away, ”explains Brown.
In the same year that Pluto was demoted, the ashes of its discoverer Clyde W. Tombaugh were sent into space on a New Horizons mission to study the dwarf planet.
“If you assume that a planet must exist and you find something, you assume it has to be.
“Lowell’s prediction was not wrong, but it was based on wrong data. It turns out that the orbits of Uranus and Neptune are not disturbed at all; both planets are exactly where they should be. But people didn’t know then. .
“The discovery of Pluto was a complete accident“.
“My jaw dropped”
In the 1930s, there were no criteria for comparing Tombaugh’s discovery or for defining what a planet is.
The concept was somewhat vague: the planet was generally somewhat dominant and round in the solar system.
So when Brown and his team discovered Eris in 2005 and revealed that she was bigger than Pluto, it was clear that things couldn’t turn out that way.
“A committee was formed, a committee was dissolved, and a new committee was formed, and a new committee was dissolved. Eventually, the International Astronomical Union, a body for this sort of thing, formed another committee with scientists and historians who made a proposal for a 2006 meeting.”
Brown did not want to get involved in this.
The future of Pluto was at stake … (Image from NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute)
“I actually hid my family on a small island in the Pacific Northwest where I assumed no one would find me. But during this meeting of the International Astronomical Union they found me and my phone started ringing …
“The proposal was that Pluto would keep its planetary status, Eris would be a planet, a series of asteroids would be a planet, and Pluto’s moon would be a planet.
“My jaw dropped: This is the craziest proposition I’ve ever seen in my life“.
If it weren’t for him, Pluto would be what many of us have learned: the ninth planet in our solar system.
But the author of How I Killed Pluto and Why He Deserved It remained silent.
“They were about to say that I discovered the planet -Eris- that would make me the only discoverer of planets with life and therefore famous, but I have argued strongly that it doesn’t make sense.
“I didn’t discover the planet. I discovered this cool little body, which is the most massive Kuiper belt object we know, and it is very amazing, but it just doesn’t have the discovery scale of the planet.
“My argument ultimately won the vote in the International Astronomical Union and that was this: Pluto was no longer a planet.
“I would say Pluto never was. The case is closed and Pluto will never be a planet again. “
The International Astronomical Union has defined a planet for the first time.
To be a planet, an object must revolve around the sun, be circular and have a clear neighborhood, in other words, it must have no other objects in the vicinity. In the latter state, Pluto failed.
“It was exciting at the time; It was not an easy decision, and the astronomers made the right one. It was amazing, I would never really have predicted it to happen“.
But although Brown tried to explain what had happened, people were furious.
Nothing will ever be the same … Suddenly this teacher got it wrong.
“In the first year, they sent me rude, hateful messages. I have received real death threats. ”
The astronomer was amazed how humans have such strong feelings about Pluto.
Still, I have no regrets.
“It was and still is scientifically correct. This is the correct classification scheme for our solar system, and it matters because it allows us to really understand what it looks like.
“Therefore, I am glad that I played a role in helping scientists and the public to describe the solar system properly.”
What is this description?
“I think the best description of the solar system is: 8 giant planets, an asteroid belt between Mars and Jupiter, and a band of objects beyond Neptune in the Kuiper belt.”