Those of us born in the last century were brought up to believe there were nine planets in the solar system. The most distant of them, Pluto, was discovered in 1930. But, because it was so far away, little was known about this mysterious world. We knew it was the smallest planet at just under 2,400 km wide – that’s about half the size of Australia. However, the discovery of similar sized objects led to Pluto being reclassified as a dwarf planet in 2006 (to find out more, read this article from 2015).
Many think that the change in status was an insult, yet, despite no longer being a planet, Pluto is still a fascinating place to explore! Here are just a few of the things we now know about Pluto – the largest of the dwarf planets:
- Pluto is an average distance of 5,913,520,000 km (almost 6 billion km) from the Sun. That’s 40 times further out than the Earth
- Pluto is named after the god of the underworld. It has 5 moons, all with appropriate names – Charon (the underworld ferryman), Hydra (a 7-headed dragon), Nyx (goddess of the night), Cerberus (the 3-headed hellhound) and Styx (the river of death)
- Pluto has an unusual orbit. At times it is closer to the Sun than the outermost planet, Neptune. The last time this happened was from 1979-1999
- A year on Pluto is as long as 248 Earth years as it takes this long to go around the Sun. A day there lasts for 153 hours
- Because it is so far from the Sun, Pluto is very cold. The average temperature is -230⁰C
- Due to its relatively small mass, Pluto’s gravity is only 25% that on Earth. If you weigh 10 stone here, go to Pluto and you’ll only weigh 35 lbs!
- The atmosphere on Pluto is very thin. That’s because the low gravity can’t hold on to much gas. The air pressure there is more than 100,000 times less than that on Earth
I don’t know about you, but I find the topic of space exploration exciting. To think that there are new worlds out there just waiting for us to visit makes me wish I was one of the lucky ones who will one day get to go there. Alas not so. I doubt that anyone will make the journey in my lifetime – but maybe they will in yours. Who knows – you might be one of those who take the trip!
If you’d like to find out more about Pluto than check out this NASA page. There is so much to learn about our neighbouring worlds.