Wolfram Alpha is great for some what-if scenarios: https://www.wolframalpha.com/input/?i=halley+comet+volume+%2F+mars+surface+area https://www.wolframalpha.com/

Wolfram Alpha is great for some what-if scenarios: https://www.wolframalpha.com/input/?i=halley+comet+volume+%2F+mars+surface+area https://www.wolframalpha.com/input/?i=halley+comet+volume+%2...