We know that the region of the universe consisting of our sun, the eight planets and their satellites, not to mention smaller bodies like dwarf planets, asteroids and comets, is known as the solar system. But do you know what constitutes the bulk of it's mass? Or why Pluto is no longer classified as a planet? Or which is the hottest planet in our solar system? Read on to find the answers to all these and more…
(a) is in orbit around the Sun,
(b) has sufficient mass to assume a nearly round shape - hydrostatic equillibrium
(c) has cleared the neighbourhood around its orbit.
> Click here to see the poster in a new tab
Sun: If I were to tell you that I am the solar system, I wouldn't be completely wrong. For I constitute 99.86% of the system's mass, with the planets, their satellites and everything else that makes up the system together accounting for the remaining 0.14%. Not much, is it?
Anyways, as I don't like to boast about it, I thought I'd rather draw your attention to the misconception that I am burning to provide you heat and light. No! Combustion really isn't an efficient process and if I were utilising it, I would have existed for merely a few thousand years. I use nuclear fusion - a much more basic, but far more efficient process.
Mercury: I'm the smallest planet and the closest to the Sun. You knew that, didn't you? But did you know that my precession - with time, my near elliptical orbit shifts slightly around the Sun, meaning that my point of closest approach doesn't happen at the same place - posed a persistent problem for astronomers till even early in the twentieth century? Only Albert Einstein's general theory of relativity could explain my orbital precession!
Venus: I'm Earth's sister and I'm hot, well literally! Mercury might be closer to the Sun, but my thick atmosphere that is almost entirely made up of carbon dioxide, a greenhouse gas, means that the average temperature is about 875° F. That's hot enough to melt even tin and lead!
Earth: I'm so full of life! Your understanding of me, however, has definitely taken time. I was thought to be flat, when in fact I'm more spherical. You even assumed that the Sun revolved around me and that I am the centre of the solar system - a belief that existed till the sixteenth-century and was only challenged finally by Copernicus' work. Will there be another planet with life? Am I special, or am I not?!?
Mars: My surface is brownish-red but you call me the Red Planet. I'm home to Olympus Mons, the largest known volcano in the solar system. With a diametre of 624 km and a height of 25 km, Olympus Mons is thrice as tall as Mt. Everest, the tallest mountain on Earth.
Jupiter: I'm not only the largest, but the most massive planet in the solar system. It might be hard to imagine, but I'm also known for speed. At less than 10 hours, I have the shortest rotational period in the solar system. So much so that it is actually responsible for my bulge near the equator, making my shape closer to that of an oblate spheroid!
Saturn: Jupiter, Uranus and Neptune might also have rings of their own, but I am definitely the "Lord of the Rings". My density is only 0.69, the least among planets in the solar system. This has led to the saying that I would float on an ocean that is large enough to hold me. I wouldn't be so sure though, as I know for a fact that my density increases dramatically as we move down towards the centre, even if my overall density is only 70% that of water.
Uranus: If Venus is the hottest, then I'm surely the coolest - the minimum temperature on my surface is -224 degrees C. We aren't at extremes always though, for we even have some queer similarities. While every other planet in the system rotates counter-clockwise, Venus rotates clockwise and I kind of roll on my sides. Yeah, you guessed it right. My axis of rotation is almost parallel to my orbital plane!
Neptune: What with Pluto losing its status, I'm now the farthest planet in the system. I'm almost 30 times as far as the Earth is from the sun, which means that sunlight takes close to four hours and forty minutes to reach me. I take 164.8 Earth years to orbit the Sun - a feat I completed for the first time since my discovery on July 11, 2011.
Pluto: Am I a planet, or am I not? I was one from the time of my serendipitous discovery in 1930, till this new definition came out in 2006. I've now be relegated of course and I belong to the category of recognised dwarf planets alongside Ceres, Eris, Makemake and Haumea. We are dwarf planets because we haven't quite cleared our neighbourhood.
