The Astronomy Thread

[icekatze]

hi hi

Direct imaging only works for detecting very large planets that are very far away from the primary.

This is really only true for current telescopes like the Hubble, which was never really designed for this task in the first place, and is very small compared to the size of vessels that are being built and used in Outsider.

The James Webb, if it ever gets off the ground, should be able to directly image very cool objects, and it's only a 6.5m diameter aperture. If the Terrestrial Planet Finder-C hadn't been defunded, it would have been able to directly detect Earth sized planets up to 30 light years away, with an 8m x 3.5m oval shaped aperture.

Put a 30 meter aperture in space and one would be able to detect Earth sized planets from a very long distance. Then there's the option of using distributed imaging, taking a hundred shuttles with, say, a 5 meter lens each and spread them out across a light second.

Not that Outsider needs to have any changes, of course. There's not much incentive to look beyond one's next jump when they can actually get there in their lifetime, but in real life, we should be starting to get direct images of terrestrial planets in the next generation or two of space telescopes.

[Arioch]

Some very nice "sense of scale" work here, but what I find particularly remarkable is that the jets from a galaxy 13 million light-years away are so huge that, if they were bright enough to be seen with the naked eye from Earth, would take up a good portion of the night sky. The galaxy itself is nearly the apparent size of the Moon.

https://apod.nasa.gov/apod/ap210804.html

Same goes for the Andromeda galaxy.

[icekatze]

hi hi

I've known that Andromeda was visible to ancient astronomers, so we could probably see it if it weren't for light pollution.

Those jets though... dang. The universe is filled with mind boggling things.

[SVlad]

so we could probably see it if it weren't for light pollution.

The level of light pollution in the cities and even in the suburbs is unimaginably high.
I've used to see night sky as a dark blue dome with several dozens of blue dot lights. And when I first saw the sky in the middle of nowhere, where the nearest settlement is hundreds of kilometres away, I was really shocked to see black sky full of stars I believed visible only from orbital telescopes.

[Arioch]

A while ago when I was working a swing shift job, when I got off work at midnight I was seized by wanderlust and drove down the Pacific Coast Highway south a ways past Monterey to a point where there weren't any major cities nearby. I pulled over at one of the turnouts and sat on the hood of my car to look at the stars. It had been hot that day, and so even though it was about 1 AM it was still about 75°F, with a gentle sea breeze. I could hear the lapping of the waves and the conversations of seals on the beach about 100 feet below.

It was slightly hazy because of the humidity, but otherwise the sky looked like a planetarium display. It was so bright that I could see satellites making their way across the sky.

[GeoModder]

The contrast can be really stark in Africa. I've seen the night sky there twice a couple dozen kilometers from the capital of the country I was in (once away of Dar-es-Salaam, and once from Windhoek). The light dome visible on the horizon when out in the open is really a blot compared to the deep 'blackness' when the light was screened.

[Demarquis]

From Sky and Telescope for June 27th, 2018:

"From antiquity through the early Middle Ages, astronomers recorded about a dozen DSOs: the Pleiades (M45); Hyades; Double Cluster — NGCs 869 and 884; Beehive Cluster (M44); M7; Coma Berenices Star Cluster (Melotte 111); Andromeda Galaxy (M31); the two Magellanic Clouds; the southern open cluster IC 2391; and possibly M41.

Allowing for latitude, all of these objects are visible from moderately dark skies with the exception of the open cluster M41 in Canis Major, which requires an extra dose of dark."

Imagine what you could see with your eyes from space!

[icekatze]

hi hi

Sort of astronomy related: An experiment to detect dark matter may have detected dark energy by accident. When their detector found a number of anomalous readings that couldn't be explained by any of the dark matter hypotheses, someone found that one of the dark energy hypotheses was a good fit. Still a long way from being accepted, but perhaps something to keep an eye on in the future.

Possible dark energy detection

[Arioch]

A new scientific paper investigates the origin of the Local Bubble and the formation of the star-forming regions on its periphery. Starting 14 million years ago, a series of of large supernovae sent out shockwaves in the interstellar medium that swept up large amounts of gas and dust on its surface as it expanded. Sol itself was outside this bubble when it was first formed, and has migrated into it since; we are now almost exactly in the center of it. The bubble is now roughly 1000 light years across.

This isn't a new idea, but it's nice to see some more comprehensive analysis of how the bubble formed. I imagine that most of the galaxy is like this, consisting of a "foam" of intersecting bubbles blown out by supernovae, compressing gas and dust at the boundaries that triggers new star formation.



News Release: https://www.cfa.harvard.edu/news/1000-l ... oung-stars
Harvard's dedicated site: https://sites.google.com/cfa.harvard.ed ... -formation

The website has a nice little interactive 3D representation of the Local Bubble and the clouds on its edges.

bubble_newplot.gif (131.94 KiB) Viewed 5885 times

https://faun.rc.fas.harvard.edu/czucker ... gure1.html
(The red region labeled "Taurus" marks the edge of Union space.)

Perhaps by coincidence, today's NASA picture of the day is of the expanding supernova bubble Simeis 147, which is estimated to be about 40,000 years old and 150 light years across. It's about 3000 light years away from us, rimward in the rough direction of Taurus.

https://apod.nasa.gov/apod/ap220113.html

[Demarquis]

Out of curiosity, where is the Hyades Cluster located in terms of the storyverse?

[Arioch]

Out of curiosity, where is the Hyades Cluster located in terms of the storyverse?

The Pleiades are about 444 light years from Sol, so that puts the Hyades cluster somewhere in Lurs territory.

[Demarquis]

Good news about James Webb Space Telescope - they completed a stage of alignment known as "fine phasing", and in the optical tests it works as intended or even exceeds expectations:

https://www.nasa.gov/press-release/nasa ... ccessfully

The "fine phasing" step of primary mirror alignment has been completed, which means that each of the eighteen mirror segments are focused and aligned with each other to within a single wavelength of light. This makes them act as a single mirror as large as the entire array. It's an incredible feat of engineering.

[DevilDalek]

Good news about James Webb Space Telescope - they completed a stage of alignment known as "fine phasing", and in the optical tests it works as intended or even exceeds expectations:

https://www.nasa.gov/press-release/nasa ... ccessfully

The "fine phasing" step of primary mirror alignment has been completed, which means that each of the eighteen mirror segments are focused and aligned with each other to within a single wavelength of light. This makes them act as a single mirror as large as the entire array. It's an incredible feat of engineering.

Yes, but can it detect blue space elf babes yet?

[GeoModder]

Yes, but can it detect blue space elf babes yet?

It can detect blue giants. Is that enough for you?

[DevilDalek]

Yes, but can it detect blue space elf babes yet?

It can detect blue giants. Is that enough for you?

You cannot cuddle or tease blue giants!
So clearly no!

[GeoModder]

I fear the Barsam don't see the humor in your remarks.

[Arioch]

I fear the Barsam don't see the humor in your remarks.

Alas, the Barsam don't see the humor in anything.

[GeoModder]

I fear the Barsam don't see the humor in your remarks.

Alas, the Barsam don't see the humor in anything.

I know, that's why I posted the remark as such
At least the baby Barsam didn't cry this time.

[Arioch]

Long exposure images of galaxies and nebulae/dust clouds never fail to leave me in awe. This image is especially remarkable because the cloud (N11) isn't even in our galaxy, but is in the Large Magellanic Cloud, some 200,000 light years away.

[Demarquis]

The shipminds of the Culture see this *all the time*.