A tale of the unending hunt for dark matter • Hacker News Board

Re: A tale of the unending hunt for dark matter

#21

Post by Steko » Thu, Oct 04, 2018, 2:14 AM UTC

acqq wrote: post #10

JBReefer wrote: post #2

Dark matter/energy always sounds like a restatement of aether - unknowable and unreachable, conceived to fill gaps in the knowledge of the period. I'm probably wrong, but the parallels are strong.

https://medium.com/starts-with-a-bang/what-astronomers-wish-... "Among the general public, people compare it to the aether, phlogiston, or epicycles. Yet almost all astronomers are certain: dark matter and dark energy exist" "When someone puts forth the hypothesis that “dark matter and/or dark energy doesn’t exist,” the onus is on them to answer the implicit question, “okay, then what replaces General Relativity as y…

> "Yet almost all astronomers are certain: dark matter and dark energy exist ... [and it explains] everything that we see."

Siegel's cheerleading overstates the case, let's check wikipedia for a more sober assessment on the consensus:

Although the existence of dark matter is generally accepted by the scientific community, some astrophysicists,[15] intrigued by certain observations that do not fit the dark matter theory ...

Re: A tale of the unending hunt for dark matter

#22

Post by jamesrcole » Thu, Oct 04, 2018, 2:17 AM UTC

> This is the epic tale of the unending hunt for dark matter ... Despite huge pots of money being poured since the 1970s into dark matter experiments on, under or above Earth, despite endless late nights spent doing calculations, and despite plenty of media coverage, researchers keep getting nowhere

It's ridiculous to refer to about 50 years of work so far as an "unending" hunt, and it's a sign of the very short-term thinking of our age.

Re: A tale of the unending hunt for dark matter

#23

Post by roywiggins » Thu, Oct 04, 2018, 3:31 AM UTC

tarboreus wrote: post #3

JBReefer wrote: post #2

Dark matter/energy always sounds like a restatement of aether - unknowable and unreachable, conceived to fill gaps in the knowledge of the period. I'm probably wrong, but the parallels are strong.

My instinct says this as well. "My equation isn't balancing, there must be something sitting on the seesaw!"

That's how we discovered that neutrinos oscillate: "missing" neutrinos. Turns out there are three types of them and they swap around.

https://en.m.wikipedia.org/wiki/Solar_neutrino_problem

"Early attempts to explain the discrepancy proposed that the models of the Sun were wrong, i.e. the temperature and pressure in the interior of the Sun were substantially different from what was believed" but in fact, it was the Standard Model that was wrong.

Re: A tale of the unending hunt for dark matter

#24

Post by simonh » Thu, Oct 04, 2018, 4:19 AM UTC

aplummer wrote: post #7

williamdclt wrote: post #4

Earlier quoted context omitted.

To be fair, physicists are quite aware of that. I'm no expert but it seems to me that theories that remove the need for dark energy are researched, and welcomed rather than mocked. Nobody is satisfied with this dark matter/energy need (especially when we know for a fact that our current fundamental theories are wrong)

The primary difference between the scientific method and religion / dogma

Even as an atheist this wound me up. Please don't sidetrack the conversation.

Re: A tale of the unending hunt for dark matter

#25

Post by simonh » Thu, Oct 04, 2018, 4:33 AM UTC

Entangled wrote: post #8

Forgive my utter ignorance but, what if black holes are not "holes" but solid spheres of massive density? There you may have your dark matter to boot.

We measure black hole mass by their gravitational effect on stars or light (through gravitational lensing). Their density doesn't matter in these calculations since their mass is pretty much the first thing we know about them.

Re: A tale of the unending hunt for dark matter

#26

Post by JohnJamesRambo » Thu, Oct 04, 2018, 5:23 AM UTC

jamesrcole wrote: post #22

> This is the epic tale of the unending hunt for dark matter ... Despite huge pots of money being poured since the 1970s into dark matter experiments on, under or above Earth, despite endless late nights spent doing calculations, and despite plenty of media coverage, researchers keep getting nowhere It's ridiculous to refer to about 50 years of work so far as an "unending" hunt, and it's a sign of the very short-term…

Well we’ve found a lot of other things in that same timespan, for reference.

Re: A tale of the unending hunt for dark matter

#27

Post by aplummer » Thu, Oct 04, 2018, 6:16 AM UTC

simonh wrote: post #24

aplummer wrote: post #7

Earlier quoted context omitted.

The primary difference between the scientific method and religion / dogma

Even as an atheist this wound me up. Please don't sidetrack the conversation.

> it seems to me that theories that remove the need for dark energy are researched, and welcomed rather than mocked

I don’t think that clarifying this 1) is structural to their process, 2) what the process is and 3) a contrasting example of “knowledge” that also covers the same topics but without this process is a sidetrack.

This isn’t an outlying case and all scientists _should_ have this view of contrasting hypothesis. This is obviously in contrast to religion.

Re: A tale of the unending hunt for dark matter

#28

Post by salty_biscuits » Thu, Oct 04, 2018, 6:46 AM UTC

JBReefer wrote: post #2

Dark matter/energy always sounds like a restatement of aether - unknowable and unreachable, conceived to fill gaps in the knowledge of the period. I'm probably wrong, but the parallels are strong.

Or like Neptune. They predicted that from orbital perturbations they couldn't explain before they found it. Much better analogy than aether. Aether was trying to fix a theory, not a measurement.

Re: A tale of the unending hunt for dark matter

#29

Post by jamesrcole » Thu, Oct 04, 2018, 7:30 AM UTC

JohnJamesRambo wrote: post #26

jamesrcole wrote: post #22

> This is the epic tale of the unending hunt for dark matter ... Despite huge pots of money being poured since the 1970s into dark matter experiments on, under or above Earth, despite endless late nights spent doing calculations, and despite plenty of media coverage, researchers keep getting nowhere It's ridiculous to refer to about 50 years of work so far as an "unending" hunt, and it's a sign of the very short-term…

Well we’ve found a lot of other things in that same timespan, for reference.

And a lot of things took much longer, thus my statement.

Also, just because something's been going on for some amount of time says nothing about how much longer it might take to get the answers.

Re: A tale of the unending hunt for dark matter

#30

Post by VintageCool » Thu, Oct 04, 2018, 3:19 PM UTC

Entangled wrote: post #8

Forgive my utter ignorance but, what if black holes are not "holes" but solid spheres of massive density? There you may have your dark matter to boot.

That doesn't actually solve dark matter.

We know that the rotational velocity of a stellar object is proportional to the mass inside its orbit and inversely proportional to its distance from the center.

From measuring the velocities of stars in other galaxies, we find that the stars distant from the core are orbiting much faster than we'd expect them to. The velocity as you go out from the center should drop off quickly; it doesn't.

Therefore we hypothesize that there is a lot more matter at the outer reaches of a galaxy than what we're seeing.

So... you need not just more mass, but mass that isn't clumpy; mass that is mostly at the outer reaches of a galaxy and not the center.

A massive black hole at the center just doesn't cut it.