semaphoreP

23 ms·

1.
by semaphoreP 5y ago
Probably pretty difficult to find too many compelling cases. The bands starlink transmits in are designated communication bands, so interference from other satellites is going to be so high that it will drown out any signals. There are astr
2.
by semaphoreP 5y ago
Astronomer here, we are thinking about doing interferometers in space[1,2], but it won't be a catch-all for everything. One reason is that the instrumentation is equally as important as the telescope optics itself, and it's non-tr
3.
by semaphoreP 5y ago
Note that in these images, the planets are unresolved. They are point sources. Point sources span multiple pixels due to the sampling theorem.
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by semaphoreP 5y ago
And this is the program that will study this system: https://www.stsci.edu/jwst/science-execution/program-informa...
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by semaphoreP 8y ago
Ah my bad, I mean that in the visible, you can't reach the diffraction limit with AO like you can in the near infrared. Certainly impressive matching HST from the ground. I don't think past 5 microns there's been a lot of sci
6.
by semaphoreP 8y ago
Adaptive optics is really only effective in the infrared. And really only in the near-infrared, as past 5 microns, we can't really see through the atmosphere. In the visible, ground-based can't match space observatories (in the vi
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by semaphoreP 9y ago
It's not the absolute value of the signal. What they're measuring the amount of water compared to hydrogen.
8.
by semaphoreP 9y ago
It's hard to measure absolute water abundances (it requires a lot of assumptions and extrapolating). This is a relative comparison of atmospheric water. We don't have relative water abundances for a lot of planets, so it's on
9.
by semaphoreP 9y ago
It will be very tough with JWST. Many of the biosignatures are small features, and not so easily detected. There's only a handful of planets for which this might be close to possible.
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by semaphoreP 9y ago
We've also been observing the universe using neutrinos (generated by the weak force). In fact, there have even been one neutrino event linked to a possible astrophysical source[1], but with less certainty than this gravitational wave&#
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by semaphoreP 9y ago
Quite possibly I think. This is both confirmation that neutron star mergers do indeed exist and create kilonova, and the first detection of an astronomical event with both gravitational waves and light. Nobel prize is only limited to three
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by semaphoreP 9y ago
Not involved in this, I'm guessing this is how it goes: there are algorithms that automatically register the image that was just taken, diff it with a reference image of the sky from before, and if there's a significant difference
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by semaphoreP 9y ago
Actually this star is not in the Kepler Field, and it is also too bright for Kepler. Even most ground based telescopes looking for transits probably haven't bothered looking at it, due to its brightness.
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by semaphoreP 9y ago
Measuring the star wobble (i.e. doppler shift) doesn't give inclinations.
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by semaphoreP 9y ago
I guess you're right. I know there aren't any observed transits, but I also don't know what the current constraints from monitoring the star's brightness for transit is (the star is actually so bright that it becomes har
16.
by semaphoreP 9y ago
This title is a bit imprecise. They detected four planets with lower bound on their masses to be down to 1.7 Earth masses. Because these planets don't transit, there are no direct measurements from their radius. They can use mass-radiu
17.
NASA has released its exoplanet detection pipeline for Kepler(github.com)
2 points by semaphoreP 9y ago|0 comments
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by semaphoreP 9y ago
I recall there were issues if you tried to modify those files in Windows. Maybe they've fixed that in recent updates, but my impression was that while I could see the files, I shouldn't be touching them.
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by semaphoreP 9y ago
It works great for me. Like others have mentioned, it's not an emulator, so I don't feel sandboxed using it. The main downside is one of the caveats they mention: "Linux files are NOT accessible from Windows." Hopefully
20.
by semaphoreP 9y ago
Yeah, I only use Venmo when I'm on the coasts. None of my friends in the Midwest have it, and maybe I'm just used to it, but it just felt inefficient to split the bill and wait for each person to pay with their own credit card rat
21.
by semaphoreP 9y ago
Optical interferometers have resolved Betelgeuse down to 9 milliarcseconds (4 x 10^-8 radians), so this isn't even the highest resolution image yet of this star[1]. [1] http://blogs.discovermagazine.com/badastronomy&#x2
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by semaphoreP 9y ago
JWST, like ground-based telescopes now, will be able to separate the light from massive Jupiter-like exoplanets from the light of their host stars. But it won't be able to see things at a resolution like this image of Betelguse (so no
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by semaphoreP 9y ago
The colors are only there to represent brightness, so the white spot is a brighter patch on the star (brighter because it's hotter).
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by semaphoreP 10y ago
Or you can think of it as precision in the number of significant digits for a number. Each floating point number can only store a certain amount of significant digits. The fractional precision on each float is the same, but the absolute mag
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by semaphoreP 10y ago
It will depend on the size of the telescope, but for all practical purposes, these planets are too close to their star to see directly. A starshade will be good for Earth-like planets at Earth-like separations around Sun-like stars though.
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by semaphoreP 10y ago
Don't know the number off the top of my head, but it should be considerably less. It should also be highly varying as some galaxies live in pretty densely packed environments (galaxy clusters), which some live in very open environments
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by semaphoreP 10y ago
A Russian billionaire is trying: https://breakthroughinitiatives.org/Initiative/3
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by semaphoreP 10y ago
It's almost all Hydrogen/Helium gas. Other larger atoms and molecules are known to exist in the interstellar medium, but it's primary gas. Also, a good way to remember the density is ~1 Hydrogen atom per cm^3.
29.
by semaphoreP 10y ago
Like others have pointed out, the combination of the planets being tidally locked so only one side gets sunlight and the strong X-ray radiation and flaring from the host star make it considerably un-Earth-like, and harder for life as we kno
30.
by semaphoreP 10y ago
I don't think we know for sure, but it'd be hard to place another star in the system and have it a) not disrupt the planets and b) go unnoticed as the primary star is so faint.

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