Mar 15, 2023 06:55 PM
https://astronomy.com/news/2023/03/will-...fy-gravity
EXCERPT: . . . Engineers have developed concepts for rotating space habitats to recreate the effects of gravity. [...] All that technology still lies in the world of science fiction, but space agencies around the world are interested in developing such habitats for long-term missions in space.
Speaking of science fiction, writers and authors love to come up with all sorts of gravity-defying gizmos, whether to provide artificial gravity for their ships or to propel their spacecraft through the universe. Unfortunately, it seems that these kinds of anti-gravity devices will remain in the realm of fiction.
To operate these devices, it would require the use of negative matter, which is a form of matter with negative mass (not to be confused with antimatter, which is like normal matter but with opposite charge). We have never observed negative matter in the universe, and we strongly suspect it can never exist, because it would violate our understanding of the conservation of momentum, which is a pretty big deal.
However, at the largest scales in space, we already observe an anti-gravity effect. We’ve known since the observations of Edwin Hubble, about a hundred years ago, that our universe is expanding – over time, the average distance between galaxies grows. But in the late 1990s, two independent teams of astronomers discovered something remarkable: Not only is the universe expanding, but that expansion is accelerating. The universe is expanding faster and faster every single day.
The name we give to this phenomenon is dark energy, and it appears to be an anti-gravity force that is repelling all the matter in the universe. Anti-gravity actually isn’t all that strange in Einstein’s general theory of relativity, which is the set of equations we use to understand how gravity works. In general relativity, any kind of tension, like the tension in a stretched rubber band, creates an anti-gravity effect. But usually this anti-gravity effect is completely swamped by the normal, attractive gravity that we’re used to... (MORE - missing details)
EXCERPT: . . . Engineers have developed concepts for rotating space habitats to recreate the effects of gravity. [...] All that technology still lies in the world of science fiction, but space agencies around the world are interested in developing such habitats for long-term missions in space.
Speaking of science fiction, writers and authors love to come up with all sorts of gravity-defying gizmos, whether to provide artificial gravity for their ships or to propel their spacecraft through the universe. Unfortunately, it seems that these kinds of anti-gravity devices will remain in the realm of fiction.
To operate these devices, it would require the use of negative matter, which is a form of matter with negative mass (not to be confused with antimatter, which is like normal matter but with opposite charge). We have never observed negative matter in the universe, and we strongly suspect it can never exist, because it would violate our understanding of the conservation of momentum, which is a pretty big deal.
However, at the largest scales in space, we already observe an anti-gravity effect. We’ve known since the observations of Edwin Hubble, about a hundred years ago, that our universe is expanding – over time, the average distance between galaxies grows. But in the late 1990s, two independent teams of astronomers discovered something remarkable: Not only is the universe expanding, but that expansion is accelerating. The universe is expanding faster and faster every single day.
The name we give to this phenomenon is dark energy, and it appears to be an anti-gravity force that is repelling all the matter in the universe. Anti-gravity actually isn’t all that strange in Einstein’s general theory of relativity, which is the set of equations we use to understand how gravity works. In general relativity, any kind of tension, like the tension in a stretched rubber band, creates an anti-gravity effect. But usually this anti-gravity effect is completely swamped by the normal, attractive gravity that we’re used to... (MORE - missing details)