1) Two neutron stars in orbit around each other are out for a walk when they come across a black hole. One neutron star turns to the other and says, "Hey, let's travel through a wormhole!"
The other neutron star replies, "Are you crazy? If we get too close, we'll be sucked in and crushed!"
The first neutron star responds, "Don't worry, we'll just travel through the wormhole to a new place in the Universe."
The second neutron star replies, "There is no way!"
The first neutron star says: "OK then, I will go alone! "
A few minutes later the two stars get crushed into an unknown state of matter inside the event horizon.
2) A neutron star and a crocodile are having a conversation when the neutron star suddenly collapses, forming a black hole.
The crocodile turns to the black hole and says, "Hey, what happened to your friend?"
The black hole replies, "He just got a little too dense for his own good."
3) The Joker is running from the police when he stumbles upon a neutron star.
"Hey, little guy," the Joker says, "I could use a place to hide out for a while."
The neutron star replies, "I'm sorry, but I don't have enough space for you. I'm already packed with a lot of mass."
The Joker responds, "Ah, well. I guess I'll just have to keep evading the law. Thanks for your help, little guy."
The neutron star replies, "No problem. Just be careful not to get too close to me. My gravity is so strong, that will crush you into neutrons."
Really nice jokes galactic intruder, thanks for posting.
I also have a good joke to share with you:
Why was the black hole kicked out of the bar?
Because it kept sucking up all the drinks (and the customers)!