Having valiantly ventured through space, I now wish to valiantly venture through time. How can that be done

Hmm, yes... you will need to find a rapidly orbiting extremely dense object, at least a neutron star or preferably a black hole. Then just ride they waves in! Guaranteed to send you back in time by at least a few nanoseconds.

You have reached an area of impossibility, a dimension of sound, sight, and of the mind, you are hoping to break through an impervious wall to enter the Twilight Zone.

Doctor Zachary Branchard is an ordinary citizen with an above ordinary mind, his pension for creativity has left him in trouble with his family and the law. But what Zachary has done, and doesn't know yet is that he has invented a device capable of breaching the walls of reality and entering another dimension. Zachary hasn't done this yet, but in the far future, he already has.

*enter scene, Dr. Branchard fiddling pointlessly with a wheel, bright light appear in the corner, Branchard looks up a police box appears*

Future Branchard: "I have come from the future where you have invented a time machine!"

Current Branchard: "But by coming to the past now aren't you altering your present so that you will never invent a time machine?""

*Future Branchard dissipates along with the police box*

Current Branchard: "just another day"

Narrator: "In the twilight zone"

Vortex slingshot effect, And remember to miss any objects coming at you when you try this. They can hurt when they hit you.

Not possible now.

Don't think we've figured that out just yet, at least in the real world.

Astrobuf

Ever heard of Doctor Who?