The planet Mars is easily spotted at the moment, over in the south-west. You’ve heard of the Red Planet, so take a look and see why it has that name. Well, perhaps it isn’t so much red as a sort of salmon colour, but it’s clearly different from most of the other stars. On Saturday 12 January it’s directly above the Moon.
Even without a telescope you can tell that it’s a planet because it doesn’t twinkle. Usually only stars twinkle, but Mars is a planet and if you have a reasonable telescope you can see that it isn’t just a point of light but has an actual disc. It may be too small to see clearly, but its size in the sky means that its light isn’t affected by turbulence in our atmosphere as that of stars is.
All stars are so distant that they are points of light, even when seen through big telescopes. They may look substantial to your eyes, but that’s really due to defects in the eye, which blur them out a bit. The symbolic star shape is due to the fact that many people don’t see dots but see bright stars looking a bit spiky.
Mars was much closer to us back in July, but it’s now trailing behind the Earth and getting farther away all the time. It’s in an orbit farther out from Earth, and moves more slowly than Earth does, so by about next May it will lose the battle to keep up with us and will be more or less behind the Sun, and will be lost in the evening twilight.
It’s now quite small as seen through a telescope, and even if you do take a look you’ll find that there isn’t much to be seen on it except a tiny little disc. Those equipped with suitable planetary cameras can probably still take photos that show a few vague details, but we’ll have to wait until October 2020 until it’s really close again.
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