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/sci/ - Science & Math

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8681436 No.8681436 [Reply] [Original]

Why is it such a certainty that dark matter exists as a halo around galaxies?
With current technology, we need something to be shining with the brightness of a billion suns just to notice it in orbit around our own galaxy; a huge cloud around our galaxy with few stars could easily be missed, let alone the same around other galaxies.

>> No.8681441

>>8681436
DUDE THE UNIVERSE LMAO
who gives a fuck. astrofags need to get a life

>> No.8681446

>>8681436
dum dum dum dum dum

>> No.8681710

>>8681436
Dark matter because space' is filled with particles aka matter. there is no real emptiness. And also because it is dark\black.

>> No.8681712

>>8681441
this

>> No.8681812

>>8681436
Galaxy rotation curves. Newtonian (and GR, but newtonian is enough to see it) predicts that spiral galaxies rotate slower in as you get further from the center. However observations show that this is not true.

Of course, apart from dark matter, this can be explained with MONDs (modified Newtonian dynamics), but the bullet cluster is very difficult to explain with MONDs but very easy with dark matter.

>> No.8681823

>>8681441
as a former astrofag, this
i'm still doing cosmology research in the astronomy department at my university and it's mind numbingly boring

>> No.8683250

>>8681436
Look and look forever and it's likely there will always be more stars farther away to be seen.
But I'd love to see some magic wall where we saw only darkness.