How do we know that time exists?

The alarm goes off in the morning. You catch your morning train to the office. You take a lunch break. You catch your evening train back. You go for an hour's run. Eat dinner. Go to bed. Repeat. Birthdays are celebrated, ...

A step towards quantum gravity

In Einstein's theory of general relativity, gravity arises when a massive object distorts the fabric of spacetime the way a ball sinks into a piece of stretched cloth. Solving Einstein's equations by using quantities that ...

Factoring in gravitomagnetism could do away with dark matter

Observations of galactic rotation curves give one of the strongest lines of evidence pointing towards the existence of dark matter, a non-baryonic form of matter that makes up an estimated 85% of the matter in the observable ...

Black holes gain new powers when they spin fast enough

General relativity is a profoundly complex mathematical theory, but its description of black holes is amazingly simple. A stable black hole can be described by just three properties: its mass, its electric charge and its ...

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