The UniverseAnswer
Could our universe be a thin sheet floating inside a bigger space?
The sheet picture starts a question; a model must explain what moves where and reproduce measured gravity.
TOPIC
gravity.
Stories and answers about #gravity
FROM THE QUESTION LIBRARY
Short answers, with sources.
The UniverseAnswer
How do we know dark matter exists if we cannot see it?
We can’t see dark matter, but we can measure its pull in five different ways, so here is the evidence, the case for changing gravity instead, and what is still unknown.
The UniverseAnswer
Is gravity a force, or a bend in space and time?
The force picture and the spacetime picture explain the same world at different levels of detail.
The UniverseAnswer
What are gravitational waves, and how do we detect them?
Laser beams and the pulse times of distant stars reveal tiny, traveling changes in space and time.
The UniverseAnswer
What is a black hole, really?
Not a hole and not a cosmic vacuum cleaner: here is what a black hole is, how we know they exist, and where the real mysteries begin.
The UniverseAnswer
What is a theory of everything, and will we ever have one?
Physics already explains three of nature’s four forces with stunning accuracy, so here is what is missing, who is trying to fill the gap, and why some great minds doubt a final theory exists.
The UniverseAnswer
What is an extra dimension, and why can’t we see one?
An extra coordinate in a model needs an experimental case before it becomes a discovery.