Does dark energy mean repulsive gravity?

Answer 1

This is a wonderful question! In general I don't think dark energy is equivalent to anti-gravity, but it's a great starting point for inquiry to be sure.

More precisely I don't think anyone really knows the answer to this question right now. Dark energy is a made up concept to account for the fact that Einstein's equations are inaccurately predicting the amount of mass/gravitational force we should observe at the galactic and larger levels of scale.

If you're really interested in answering questions like this - consider studying physics at a university! But don't get bogged down with researching String Theory because it's probably wrong. Quantum Gravity Research Institute in California is coming up with some new tentative theories that are very interesting and more likely to be candidates to explain dark energy phenomenon than modern string theory research.

You're asking big questions, so be patient and don't expect the answers other people give you to be sufficient. We barely know anything about this universe, so stay curious :)