Question: 1)Can u build an igloo on the moon? 2)Appart from stars and black holes are there and PLANETS bigger than the sun if so what are they?

Mark Mirmelstein answered on 6 Mar 2018:

Hi Perry, thank you for the interesting questions!

1) In theory – yes! However, it also depends where, and how long you want it to last 🙂 As the moon doesn’t have a thick atmosphere like Earth does, it means that the temperature on its surface is directly related to whether the sun shines on it or not. This means that if a part of the moon is facing the sun, temperatures on it will be extremely hot, around 127 degrees Celsius! When a part of the moon is facing away from the sun, it gets extremely cold, around -173 degrees Celsius. So if you want to build an igloo, you can do so on a side that doesn’t face the sun, however once that side will face the sun the igloo will melt. It is believed that there is ice on the moon, mostly in caves, so it can be used to construct the igloo, and such cave may be a possible location for a more stable igloo.

2) A start usually forms when enough matter is condensed, and fusion is starting to occur in its core. This means that when you have a big enough density, you will get a star rather than a planet. This may be why there are no planets bigger than our sun. However, there are some stars out there which are smaller than our sun, and are also smaller than a few exoplanets that we found! This may mean that we do not yet fully understand what may be the limit between a planet and a star when it comes to its first evolutionary stages.