Space is an almost perfect vacuum full of cosmic cavities. And in short, Heaviness is responsible. But to really understand the vacuum of our universe, we need to take a moment to understand what a vacuum really is – and what isn’t.
What is a vacuum and why is space not a real vacuum?
First, forget about the vacuum cleaner as an analogy to the vacuum of space, Jackie Faherty, senior scientist in the Department of Astrophysics at the American Museum of Natural History in New York City, told Live Science. The household cleaning machine effectively fills up with dirt and dust vacuumed from your carpet. (That is, the vacuum cleaner uses differential pressure to create suction. Sucker may be a better name than vacuum cleaner.) But the vacuum of the room is the opposite. By definition, a vacuum is free of matter. The space is almost an absolute vacuum, not because of the suction, but because it is almost empty.
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This emptiness leads to extremely low pressure. And while it is impossible to emulate the void of space on Earth, scientists can create extremely low pressure environments known as partial vacuums.
Even with the vacuum cleaner analogy, “understanding the concept of vacuum is almost alien because it is so contradictory to our existence,”
Gravity is king
On average, the room would still be pretty empty even if we didn’t have gravity. “There’s just not a lot of stuff relative to the volume of the universe you put that stuff in,” said Caltech theoretical astrophysicist Cameron Hummels. The average density of the universe, according to NASAis 5.9 protons (positively charged) subatomic particle) per cubic meter. But then gravity increases the void in certain regions of the universe by causing matter to congregate in the universe.
Basically, any two objects with mass are attracted to each other. That’s gravity. In other words, “Matter likes to be around other matter,” said Faherty. In space, gravity pulls nearby objects closer together. Together, their collective mass increases, and more mass means they can create a stronger force of attraction that allows them to pull even more matter into their cosmic clumps. The mass increases, then the attraction, then the mass. “It’s an out of control effect,” said Hummel.
As these gravitational hotspots attract nearby matter, the space between them is evacuated, creating something called a cosmic emptinessSaid Hummel. But the universe didn’t start out like this. After this Big BangThe matter in the universe is more evenly distributed, “almost like a fog,” he said. But over billions of years, gravity has collected this matter in asteroids, planets, stars, solar systems, and galaxies. and between them the cavities of interplanetary, interstellar and intergalactic space.
But even the vacuum of space is not really pure. Between galaxies there are less than an atom in every cubic meter, which means that intergalactic space is not completely empty. However, it has far less matter than any vacuum that humans could simulate in a laboratory on Earth.
In the meantime, “the universe continues to expand,” said Faherty, assuring that the cosmos will remain largely empty. “It sounds so lonely,” she said.
Originally published on Live Science.