Do you miss Pluto? In 2006, the International Astronomical Union voted this dwarf world off the island. It was no longer a planet – a peer of Mars, Jupiter and the rest. From then on, Pluto will be known as a dwarf planet, a stealthy designation that only an astronomer could like. And personally, I didn’t.
Pluto will now be known as the dwarf planet, a stealthy designation that only an astronomer can love. And personally, I didn’t.
Of course, the decision made astronomical sense, but the ninth planet was my sentimental, enigmatic and beyond the capabilities of my little homemade telescope. All the other planets had been mapped and photographed. They were familiar to anyone who could read. But not Pluto.
A few months before the astronomical union retrograde Pluto, NASA launched the New Horizons spacecraft to map it – the only planet whose face we still hadn’t seen. What a disappointment long before New Horizons arrived in 2015, Pluto had become an ex-planet.
But just as planets can be lost, so can they be found. And I hope for a replacement for Pluto. Astronomers sift through the skies for a great, new world that lurks in the solitary backcountry of the Solar System, a world that no one could ever deny the planet of.
What could be the gain in finding a cold, dark, lonely world in the lower regions of the solar system? The main benefit for science would be to help us understand how solar systems are formed. And you can be sure that NASA plans to send a probe in its direction soon.
But to me, such a vast and distant world has a romantic appeal, more than Pluto ever did. I can imagine its future use as a staging station for missions to the stars, either as a staging area or simply as a booster for long-range probes that could use it to launch into the depths of space.
This is not a random search. For most of the 20th century, Pluto was believed to mark the end of the planetary road – the last gas in the solar system. It was the only large body beyond Neptune. (Yes, there are billions of comets much further away, but they are small. Most could fit in Central Park in New York City.)
But in the 1990s, astronomers began to find hundreds of objects beyond that supposed limit. Some were just comets, but there were also beefier bodies – balls of rock and ice hundreds of miles across. They’ve been given strange names, like Makemake, Lempo, Haumea, and Quaoar.
Astronomical union realized the problem that this created. After all, if Pluto was a planet (which it was then), Makemake et al. They also revolved around the sun and were comparable in size to Pluto. But that would make a lot of planets. Finally, believing that the astronomical community had to face this situation, the group decided in 2006 to simply throw all these icy rocks into another box and name it “dwarf planets”. Pluto was simply the first to be found.
But this story has a twist, which makes it more than semantics. Observations show that the most distant so-called transneptunian objects have roughly aligned orbits. It’s suspicious. Imagine throwing a dozen pencils in the air, after which you examine their orientation on the ground. You wouldn’t expect almost all of them to point in the same direction. But it was true for the orbits of these distant objects.
In 2016, California Institute of Technology astronomers Mike Brown and Konstantin Batygin suggested an explanation. They argued that these objects were slowly dragged into this unlikely alignment by the gravitational tug of an unknown, heavy planet.
Most of the planets that we have detected around other stars have been revealed by the slight dance that their gravitational pull induces in their host stars.
It was certainly possible. In the 1840s, slight irregularities in the movement of Uranus aroused the suspicion that an invisible planet, further in the solar system, was pulling over this world. This led to the discovery of Neptune. Most of the planets that we have detected around other stars have been revealed by the slight dance that their gravitational pull induces in their host stars. Finding something by its influence on a neighbor is an old story in astronomy.
Brown and Batygin thought they would find this hypothetical planet within two years. But that did not happen. Recently, new findings have caused them to slightly revise their prediction. It is now believed that Planet 9, if it exists, will be about half the mass of Uranus. It might not seem like much, but it’s more than the combined weight of Mercury, Venus, Earth, and Mars. Formed in the outer solar system, this planet would probably be a ball of cold gas; like Jupiter and Saturn, although smaller, in a realm where the sun is nothing more than a shining point in an inky sky. So, forget planet 9 as a candidate for future colonization.
But why is it so hard to find? Well, with an estimated distance from the sun of 10 times that of Pluto, Planet 9 would be darker than a cane toad. Also, the predictions only give a general idea of where to look for this world. Finding Planet 9 won’t be easy, even assuming it’s there.
Caltech astronomers are unfazed and continue their research. They comb through existing astronomical data and plan to introduce new telescopes for research, such as the Vera Rubin Observatory.
For my part, I support them. In my opinion, Planet 9 would one day be the last stopover for our descendants before they enter the dark seas of the Last Frontier.