[HN Gopher] Local detection of dark matter with future missions ...
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Local detection of dark matter with future missions to Uranus and
Neptune
Author : ArtWomb
Score : 54 points
Date : 2022-04-19 15:25 UTC (7 hours ago)
(HTM) web link (arxiv.org)
(TXT) w3m dump (arxiv.org)
| Baopab wrote:
| There's also a Cambridge study from ~1 year ago that could be the
| first direct detection of dark energy in an experimental dark
| matter detector. I can't seem to find it again though...
| Sporktacular wrote:
| Please link if you find it.
| scld wrote:
| Layman here: Does this mean that they'll launch orbiters around
| Neptune and Uranus and, by measuring the doppler shift in comms
| back to Earth against their simulations, determine if there's
| enough dark matter to be impacting the doppler shift?
| goodcanadian wrote:
| No, or not exactly. It appears to me that they are suggesting
| (or rather, modelling) using the doppler shift to precisely
| measure the trajectories of the spacecraft on the way to those
| planets in order to get a measurement of the gravitational
| field that is acting on them and thus a measurement of any dark
| matter that may be present.
| rich_sasha wrote:
| Hmm, but if we're suspended in a homogeneous "soup" of Dark
| Matter, the surely such forces would cancel out?
|
| Do we except Dark Matter to be distributed inhomogeneously
| around the Solar System? I thought it is only in homogenous
| at ~galactic scales.
| treeman79 wrote:
| https://xkcd.com/2186/
|
| Earths dark matter is equivalent to one squirrel.
| rich_sasha wrote:
| Right, but even that link suggests dark matter is pretty
| homogeneous around Solar System, right? If it's simply
| described as a density number.
|
| Is the suggested experiment just measuring that
| homogeneous density? Or hoping to find some distribution
| around the Solae System?
| flqn wrote:
| We've only been able to infer dark matter densities over
| galactic scales so I'm not sure that density applies at
| planetary system scales. It's like trying to use the
| density of iron to say where the atoms in a chunk of it
| are.
| [deleted]
| enkid wrote:
| Warning, I am also a layman, but I don't think we know how
| clumped dark matter is. We know it has to be spread out on
| galactic scales, but that doesn't mean it's spread out at
| solar system scales. Some people even suggest dark matter
| could be black holes with intermediate masses. If we can
| figure out how concentrated or spread out dark matter is at
| the solar system level, it constrains the models that would
| fit the new data.
| Sporktacular wrote:
| How do they propose differentiating the gravity due to normal
| matter from dark matter?
| goodcanadian wrote:
| Basically, we can see the normal matter.
| [deleted]
| waynecochran wrote:
| It's cool there is a "Code & Data" link for papers at arxiv (alas
| there is "No official code found" for this paper -- not that I
| expect there would be).
| zionic wrote:
| This is random but I really want to get some high end instruments
| in geosynchronous orbit with Jupiter/one of the gas giants
| opposite the sun. Seems like the perfect place to get low-noise
| measurements.
| krisoft wrote:
| It sounds more like what you are saying is you want instruments
| orbiting around the L2 lagrange point of the Jupiter-Sun
| system. Do I understand you right?
|
| At first I was confused because the "geo" in geosycnronous
| means that the orbit is centered around the Earth. But you are
| talking about Jupiter, so I thought maybe you mean a
| "jovisyncronous" orbit? One orbiting around the Jupiter with
| the same orbital period the Jupiter rotates with. But then you
| also say opposite the sun, and that orbit would be on the
| opposite side from the Sun only some of the time (because
| Jupiter is not tidaly locked with the Sun). So my best guess
| now is that you mean L2.
|
| What kind of measurement would you want to do there? And how
| would you get the results back to Earth?
| throwawayboise wrote:
| Queue the jokes about studying dark matter on Uranus.
| rich_sasha wrote:
| I'll stick to M'ars
| Sharlin wrote:
| *cue. As in, a theatrical cue to enter the stage.
| sdflhasjd wrote:
| No, this is the line for a queue of these jokes. ;p
| throwawayboise wrote:
| I wondered about that, I chose queue as in "line up the
| jokes"
| kzzzznot wrote:
| Now you've said that, I think I prefer it
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