A new tool for finding dark matter digs up nothing

Re:A new tool for finding dark matter digs up nothing by Maursault on Tuesday March 22, 2022 @02:13PM (#30769449)

The reasons given for Dark Matter always begin with galaxy rotation curves (the galaxy rotation problem and the galaxy winding problem). But the problem with this "evidence" is that the observations were made of galaxies in isolation, but even galaxies are not gravitationally isolated.[1] I can not speak to the veracity of the rest of the evidence for Dark Matter, but galaxy rotation curves can no longer be counted as evidence of Dark Matter because they are more simply explained by a gravitational phenomenon caused by the out of frame mass of other nearby galaxies.

[1] https://www.youtube.com/watch?v=PL0ewiwqoTw&t=4m5s

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Re:A new tool for finding dark matter digs up nothing by alecst on Tuesday March 22, 2022 @02:27PM (#30769639)

There are many theories of dark matter given at conferences like this. Around that time (2013-2014) I remember hearing about axion theories too. I don't know anything about this person's presentation so I can't say how it displaces the problem of galaxy rotation curves. If the math checks out, I think it would have, but you never know. I would like to see a reaction from cosmologists.

I would hesitate leaning too much on the always part. Fritz Zwicky was the first to notice the anomalous galaxy rotation curves and propose dark matter (is the story that I remember, anyway.) This is probably why it's presented first. It does not mean that it's the most important piece of evidence.

I'm intentionally writing with a light touch here because I don't consider myself an expert in the field.

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Re:A new tool for finding dark matter digs up nothing by russdill on Tuesday March 22, 2022 @05:11PM (#30771611)

Explanations always begin with Galaxy rotation curves because that's how it was first notified that something about our understanding of the universe was off.

It's been a long time since then and there's been a ton more data collected about wide ranging phenomenon since.

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Re:A new tool for finding dark matter digs up nothing by pdonis on Tuesday March 22, 2022 @03:26PM (#30770348)

> a gravitational phenomenon caused by the out of frame mass of other nearby galaxies

There have been papers published on this, but it is still speculative, so it's premature to say that this kind of alternative theory rules out dark matter.

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Re:A new tool for finding dark matter digs up nothing by Maursault on Tuesday March 22, 2022 @03:44PM (#30770563)

> it's premature to say that this kind of alternative theory rules out dark matter

No, it only eliminates the need for Dark Matter to explain galaxy rotation curves.

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