Blue shift, it’s moving towards you, the photons are being “compressed” to a higher, bluer frequency. Redshift, the light is being “stretched” to a lower, redder frequency. Both only noticeable at significant fractions of the spped of light, relativistic speed.
Something ominous about the post is that a cosmic object that is moving towards you at a steady rate is consided “blueshifted” in the past tense, it’s velocity is steady. If a galaxy is “Blueshifting” in the present tense, then that galzy is somehow accelerating at you, which is impossible unless it’s under direct control by an entity, presumably a kardeshev level 3 civilization.
Isn’t the rate of expansion in the universe increasing, and at an uneven rate at that? Meaning it could just as easily be an as of yet unknown natural phenomenon?
The expansion is supposed to be happening everywhere at the same time, not just at the edges.
For example, tomorrow there should be more space between the Sol and Alpha Centauri systems than there was yesterday.
Our present understanding suggests that ‘normal’ universal expansion should not (in and of itself) result in anything moving towards us.
Yes, but not because of universal expansion really, they’re just headed in a direction that is going to intersect at some point, likely combining the two galaxies together. This’ll be so far in the future we’ll all be long dead though, on top of it being unlikely that anything is going to even come close to our solar system
Blue shift, it’s moving towards you, the photons are being “compressed” to a higher, bluer frequency. Redshift, the light is being “stretched” to a lower, redder frequency. Both only noticeable at significant fractions of the spped of light, relativistic speed.
Something ominous about the post is that a cosmic object that is moving towards you at a steady rate is consided “blueshifted” in the past tense, it’s velocity is steady. If a galaxy is “Blueshifting” in the present tense, then that galzy is somehow accelerating at you, which is impossible unless it’s under direct control by an entity, presumably a kardeshev level 3 civilization.
Isn’t the rate of expansion in the universe increasing, and at an uneven rate at that? Meaning it could just as easily be an as of yet unknown natural phenomenon?
The expansion is supposed to be happening everywhere at the same time, not just at the edges.
For example, tomorrow there should be more space between the Sol and Alpha Centauri systems than there was yesterday.
Our present understanding suggests that ‘normal’ universal expansion should not (in and of itself) result in anything moving towards us.
Aren’t the milky way and andromeda on a collision course with each other?
Milky way and Andromeda are close enough that expansion is too small to overpower gravity
Our local group is racing toward The Great Attractor but will never reach it as expansion is pulling it away faster than we’re falling toward it
Yes, but not because of universal expansion really, they’re just headed in a direction that is going to intersect at some point, likely combining the two galaxies together. This’ll be so far in the future we’ll all be long dead though, on top of it being unlikely that anything is going to even come close to our solar system
That’s the other part I find fascinating; these two galaxies are gonna intersect, but our solar system probably won’t hit anything. That’s so gnar.
Galaxies are gravitationally bound, they do not expand in the same way as the universe.
Fair enough, I should have been thinking bigger.
Expansion red-shifts light.