When you die I think that's it. You're just dead. When I think about all the different forms of life and I try to insert them into the heaven/hell thing it just doesn't seem to work out. What happens when a plant dies?
Of course there are aliens. On Mars there with bacteria at one time so who knows how many billion species are alive somewhere else. A some (if not many) may be at our level or far beyond in intelligence and technology. As for all the UFO sightings and alien abductions, I'm not sure what to think. It might be the military, it might be just stupid people. Maybe in one way or another alien life has contacted our planet.
As soon as we make friends with the aliens we'll get the information on how to travel that fast.
And now for time travel. You'll need to set up a wormhole that can stay open continuously. From a future moment connect to that wormhole and travel back to that time. So in the future you may have a network of wormhole transporters. The thing with that is you'll only be able to travel as far back as when the wormhole was created, so no dino egg stealing for you. I guess wormholes could also be used in space travel. Send a group ahead and open a wormhole. Now all we need to do is figure out how to use this device.