“A few centuries ago, the pioneer navigators learnt the size and shape of our Earth, and the layout of the continents. We are now just learning the dimensions and ingredients of our entire cosmos, and can at last make some sense of our cosmic habitat.” -Martin Rees
In our Solar System, Jupiter is the largest planet we have, but what’s the upper limit to planetary size?
If you get too much mass together in a single object, its core will fuse lighter elements into heavier ones.
At about eighty times the mass of Jupiter, you’ll have a true star, burning hydrogen into helium.
The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.