Among Other Significant Events of 2025

The third one is fascinating and should prove to people that 99% of us have no comprehension of the enormity of the universe.

In 365 days the Andromeda Galaxy traveled 3.5 billion km closer to the Milky Way Galaxy and in another 4 billion years both will collide.


And Andromeda is our next door neighbor cosmically speaking.

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No one's "measuring" anything, it's a theoretical average movement based on prior observations and assumptions

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To the millimeter level? No one is observing or even assuming that. bullshite.

Land surveys have a higher margin of error than that.

So not really a "significant event" then.

Not actually an event at all, just BS.

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So not really a "significant event" then. Not actually an event at all, just BS

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and chances are it isn’t even true -it’s just ‘theory’

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I don't believe for one second that they can measure space down to the centimeter level, much less the millimeter level.

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lasers and math

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That’ll be cool to watch.

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The leading theory is that, from a human on Earths perspective you would notice anything. (If Earth were still around by then - the Earth will be engulfed by the sun in ~5 - 7 billion years when our sun become a red giant)

and it will take between 2 and 6 billion years after contact for things to settle out in the new "Milkomeda" galaxy.

It's thought that Andromeda has cannibalized at least 2 other galaxy's and now we're next on the menu.

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In 365 days the Andromeda Galaxy traveled 3.5 billion km closer to the Milky Way Galaxy and in another 4 billion years both will collide.

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To put the enormous scale into perspective, when this happens it could very well be that nothing actually hits each other.

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To the millimeter level? No one is observing or even assuming that. bullshite.

Land surveys have a higher margin of error than that.

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Not sure where you’re getting “millimeter level” from OP. That being said, the other guy is mistaken. We actually do have direct measurements of the Moon’s rate of recession from Earth.

Astronauts left reflective panels on the surface of the Moon during the Apollo missions. Scientists have been running experiments for the past 50 years, where they fire a laser at the reflective panels from Earth and measure the amount of time it takes for the light to return.

You’re probably correct that this would not be precise enough to accurately measure the recession over a single year. But over 50 years, there’s enough data that they can approximate the Moon’s average recession at ~3.8 cm/year.

The rate of Earth’s recession from the Sun is more of a calculation based on a model, as the other guy said. We can calculate the amount of energy released by the Sun as electromagnetic radiation using direct measurements. We can then determine the mass lost to fusion using E=mc^2. Meanwhile we can also estimate the mass lost to solar wind using measurements from satellites and probes. Once you have an estimate of the amount of mass the Sun loses each year, you can calculate how that change in mass impact Earth’s orbit.

All of that said, OP is a bit misleading in the sense that these aren’t estimates for 2025 specifically; they’re annual averages based on a long history of data collection. We know that some (all?) of these rates will change over time, but the timescale is so long compared to the history of human measurement that there’s no point trying to factor that in.