Ask HN: Can the expansion of space be detected on earth itself?

https://news.ycombinator.com/item?id=33995495

by desertraven • 4 years ago

1 1 4 years ago

news.ycombinator.com

Someone• 4 years ago

No. On earth there are too many forces holding things together to make earth expand.

https://www.forbes.com/sites/startswithabang/2020/11/06/ask-...:

“The expansion rate of the Universe, as we measure it (even with our current ongoing controversies), is somewhere around 70 km/s/Mpc, which means that for every Megaparsec away a “raisin” is, we’ll see it appear to recede at 70 km/s. Unfortunately, Megaparsecs are enormous: about 3.3 million light-years. If we scaled that down to the size of planet Earth — which is more like 12,700 km in size — we’d expect to see the Earth expanding by about 0.1 millimeters-per-second. Over time, that would add up significantly, and we’d notice.

Our detailed measurements show that, at least on Earth, objects aren’t expanding. Even with the enormous scale of the Universe and the relatively tiny size of the planet and the objects on it, it’s possible to do experiments to tell. The LIGO gravitational wave detectors are sensitive to changes in distance as small as less than 0.1% the width of a proton. Quantum mechanical experiments can measure the properties of atoms down to precisions of 1-part-in-billions, and precise measurements from decades or even a century apart can be compared. The answer is in, and we know: neither the Earth nor the atoms on it are changing in this fashion over time.”

Ask HN: Can the expansion of space be detected on earth itself?

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