How Big Is Comet 67P?

Mosaic image of Comet 67P as seen from Rosetta. Image: ESA

Everyone likes the Rossetta mission to visit comet 67P. Personally, I like the different images that show the size of the comet next to everyday objects like Paris or a Star Destroyer. This has inspired me to make my own comparisons. Below I will create illustrations with Comet 67P and some of the large things I have featured in my blog (from the past).

A Mole of Salt Grains

In October, chemists like to celebrate Mole Day (October 23). They get this day because 1 mole is 6.02 x 10²³ – so 10/23. However, the big problem with a mole is that you can’t find something that you can both see the individual things and a mole of those things. I tried this by calculating the size of a mole of salt grains. It’s pretty huge.

Here is comet 67P next to the salt cube.

A Cashteroid

I define a cashteroid as a big pile of money (usually in space) such that it is bound together by its own gravitational forces and has a surface gravitational field large enough that you could walk on the surface (with a space suit). The first time I looked at a cashteroid, it was to show the size of one trillion dollars.

Here is the cashteroid next to comet 67P.

You probably can’t tell, but the International Space Station is right next to the cashteroid.

The Atlanta Airport

You know I like the Atlanta airport. It’s just so straight and long it seems like you could use it to see (or measure the) the curvature of the Earth. Oh, the terminal is about 725 meters long.

Here is one of the terminals next to Comet 67P.

The Atlanta airport has 6 of these 725 meter long terminals. If you lined them up, end to end, they would be about the length of Comet 67P.

A Scale LEGO Model of the Death Star

Of course the best Star Wars LEGO model of all time was the scale model of the Millenium Falcon. No, not the one you see in stores – this one for 5,000 dollars.

In a previous post, I calculated the size of the Death Star if it were built from LEGO and to the same scale as the mini fig. I’m not going to spoil it and tell you the size of the LEGO Death Star. Let me just show you the comparison with Comet 67P.

Remember, that’s not the Death Star – that’s a LEGO Death Star for minifigs. Even cooler is this: if both the LEGO Death Star and Comet 67P were in orbit around the Earth at the altitude of the ISS, they would appear about the same angular size as the moon. That would be cool to see.