“What are you talking about? Gravity is the force of attraction that makes things fall straight down.” But say it to a physicist, and the answer you’ll get is, “That’s right.”
I know, because those are the two answers I’ve been getting for the past few years, ever since I figured out that nobody knows what gravity is, and that just about nobody knows that nobody knows what gravity is. The exception is physicists: They know that nobody knows what gravity is, because they know that they don’t know what gravity is.
ESO’s exquisitely sensitive GRAVITY instrument has added further evidence to the long-standing assumption that a supermassive black hole lurks in the centre of the Milky Way. New observations show clumps of gas swirling around at about 30% of the speed of light on a circular orbit just outside a four million solar mass black hole — the first time material has been observed orbiting close to the point of no return, and the most detailed observations yet of material orbiting this close to a black hole.
The artist impression of the ejection mechanism by the supermassive black hole. Credit: James Josephides (Swinburne Astronomy Productions)
“My favorite part of this discovery is thinking about where this star came from and where it’s going,” said Ji. “It was born in one of the craziest places in the universe, near a supermassive black hole with lots of other nearby star friends; but it’s going to leave our galaxy and die all alone, out in the middle of nowhere. Quite a fall from grace.”
Five million years ago, when humanity’s ancestors were just learning to walk upright, a star was ejected from Sagittarius A*, the supermassive black hole at the center of the Milky Way Galaxy, at a staggering 3.7 million mph. This month, a group of researchers spotted the superfast star traveling relatively close to Earth.
Our sun orbits the galaxy’s center, so many dinosaurs roamed the Earth while the planet was on the other side of the Milky Way.
Our solar system’s orbit keeps us just the right distance from the galaxy’s chaotic center for life to exist.
As head of state, the monarch remains publicly neutral when it comes to political matters and does not express her views. But commentators were likely to see her words as a veiled reference the debate on Britain’s departure from the EU.
Similar in tone to her Christmas Day address, the Queen expressed the importance of “never losing sight of the bigger picture”.