Answers for Allensbank

The other week I gave a talk at Allensbank Primary School – a nearby school for children aged 4 to 11. I mainly told them about the planets and the Solar System but obviously we got onto other topics too. We had a fun questions and answers session at the end but there is never enough time – in light of this many of them sent me letters with more questions.

What is Your Favourite Planet?

Shaheer, Esme and Thea all want to know what my favourite planet is. It’s an important question. At first I want to say that the Earth is my favourite planet but that’s cheating, isn’t it? In which case, I think it has to be Jupiter.

Jupiter Through a Telescope

Jupiter was one of the first planets I looked at through a telescope (I was 12) and when you do that you can see that it has four very bright moons. These moons are called the Galilean Moons because they were observed by Galileo, the first man to look at the sky with a telescope – and that was 400 years ago! You can also sometimes see that Jupiter is stripy and that it has a big, red spot. Saturn is also good to look at  – with its bright rings – but Jupiter changes every night, which is very cool and interesting. The moons move and the stripes and spot rotate around the planet.

Why are There Craters on the Moon?

Sean asks why there are craters on the Moon. The answer is that that space is not empty. The Solar System is a very busy place. As well as planets and moons and the Sun, there are also other objects in the Solar System. yoiu might remember I talked about comets and asteroids. These are rocky bodies, smaller than planets, that also go around the Sun. There are also even smaller rocks out there, flying around. Quite often these rocks hit the larger planets and moons. The craters on the Moon are the left over pock-marks from rocks hitting the surface of the Moon.

We see craters all over the Solar System. Mercury and Mars are covered in them, and so is any other object that is rocky and not covered in clouds. Even the Earth is hit by rocks sometimes. We can see some craters here on Earth! They are harder to find because of all the grass and volcanoes and glaciers and rivers covering them up – but sometimes they are found. They can be very big!


There is a very big crater in Arizona in the USA called Barringer Crater – I have put a picture of it here for you. It is 1,200 metres across (nearly a mile) and it was formed 40,000 years ago when a 50-metre wide rock crashed into the Earth from space.

You can play with a fun Earth-smashing, asteroid simulator called Down2Earth. It lets you try and smash all sorts of different sizes of rock into the Earth and see what damage they would do.

Living on Other Planets

Thea asks whether people live on other planets. Currently no, they don’t. People do live in space now. There is always a crew onboard the International Space Station. New astronauts arrive to change-over roughly once every six months.


A lot of people think we should go back to the Moon one day and set up a Moon base so that we can learn how to live on other planets and maybe mine the Moon for minerals – like we mine the Earth. Living on the Moon might mean that we can figure out how to go and live on Mars one day too.

I’ll leave it there for now. I have more questions to answer but I’ll leave that for part 2. A lot of you said how much you liked the images of the nebulae that I showed you. At the top of this post you’ll see a lovely picture of the Orion Nebula from the Seeing in the Dark website.


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