
NASA’s InSight detects Phobos using its seismometer during solar eclipses - sohkamyung
https://ethz.ch/en/news-and-events/eth-news/news/2020/09/surprise-on-mars.html
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sambroner
Very neat article. Nasa and ETH Zurich noticed the Martian moon Phobos during
the eclipse using a seismometer. The effect is tiny, but their hypothesis is
that this is caused by the top level of ground rapidly cooling. The effect can
be used to determine the material of the ground. Separately, this can help
determine Phobos' orbit more accurately.

> _“This tilt is incredibly small,” Stähler notes. “Imagine a 5- franc coin;
> now, push two silver atoms under one edge. That’s the incline we’re talking
> about: 10-8.” As slight as this effect was, it was still unmistakable._

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natcombs
That is incredible sensitivity. How does one calibrate something, or also not
suspect the instrument is affected by other environmental variables?

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dreen
Considering the Moon could have a similar (but stronger due to totality)
effect on Earth during a Solar eclipse, could the Moon cause an earthquake?

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sambroner
This seems to be caused by heat, not the gravity. The article includes a story
about a lamp being left on in a mine that caused enough thermal expansion to
be measured by a seismometer.

Presumably the solar eclipse could be measured as well.

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dreen
I did mean the heat, not gravity. A Solar eclipse on Earth blocks all direct
sunlight for about 10 minutes. My question is would that be enough to cause an
earthquake, by suddenly cooling an area of the planet.

I also realise the night blocks sunlight for way longer, but maybe this is
different because the effect is spread out. During eclipse we have the planet
all around the area of eclipse heated up and a comparatively small area not
being heated in the middle.

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macintux
I suspect, without having any real clue, that you’d see greater localized
extremes in temperature with a pop—up thunderstorm.

I’d have a hard time believing earthquakes could result from that (although
the science & engineering in this article are enough to make me believe just
about anything is possible).

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Sharlin
Do lightning strikes/thunderclaps register on seismometers? Apparently yes:
[1][2]

[1]
[https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/91JD...](https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/91JD00789)

[2]
[https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2007...](https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2007GL030404)

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sitkack
So do rivers and animal migrations.

[http://www.geologypage.com/2019/11/studying-the-snowmelt-
epi...](http://www.geologypage.com/2019/11/studying-the-snowmelt-episodes-of-
a-pyrenean-river-with-a-seismometer.html)

[https://pubmed.ncbi.nlm.nih.gov/25618038/](https://pubmed.ncbi.nlm.nih.gov/25618038/)

[https://www.researchgate.net/publication/251437544_Seismic_w...](https://www.researchgate.net/publication/251437544_Seismic_waves_from_elephant_vocalizations_A_possible_communication_mode)

[https://abcnews.go.com/Technology/DyeHard/elephants-
predict-...](https://abcnews.go.com/Technology/DyeHard/elephants-predict-
earthquakes/story?id=8643318)

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rossdavidh
Wow, Phobos has a seismometer? Neat!

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SirLuxuryYacht
NASA's InSight lander is located on the surface of Mars. There are no
synthetic objects on Phobos (please correct me if I'm wrong).

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Normille
Phobos has a seismometer?

This is huge news, as it's a positive sign of intelligent life having evolved
there.

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mhh__
God forbid! A joke on the internet?

