The Astronomy Thread

Discussion regarding the Outsider webcomic, science, technology and science fiction.

Moderator: Outsider Moderators

User avatar
GeoModder
Posts: 1038
Joined: Mon Mar 21, 2011 6:31 pm

Re: The Astronomy Thread

Post by GeoModder »

Imagine what you could do if you could add a couple telescopes on the moon to this setup.
Image

User avatar
Mithramuse
Posts: 45
Joined: Mon Jul 23, 2018 7:39 pm

Re: The Astronomy Thread

Post by Mithramuse »

Arioch wrote:While one can never say with a straight face that the first image of a black hole isn't cool, I can't help but be slightly disappointed that the black hole imaged was in the giant, distant M87 galaxy instead of Sag A* in our own Milky Way (which is what the pre-release hype seemed to indicate), and that the image essentially looks exactly as predicted. Sure, it's great to have existing theories confirmed, but it also means that we didn't learn anything new. (Though no doubt the boffins will tease many interesting new tidbits out of the data in the coming months and years.)
I think the Sag A* data is still being processed. Maybe due to there being more dust etc. in the way?

And yup, maybe a bit less exciting than hoped for, but I think the main tidbits to come will be once we do start comparing the various black holes that we will now be able to image... picturing one of something is nifty, but hard to confirm/deny anything. Get a couple dozen black hole pictures (or more), and there will likely be something to talk about!
Arioch wrote:What I'm really excited about is what they can do with the Even Horizon Telescope (the network of radiotelescopes used to capture the M87 black hole data) and other systems like it in the future. Imagine what you can do when you can image objects down to the resolution of a solar system at 50 million light years. A bit like the gravity wave observatories, this marks a new era in astronomy.
Agreed, there. :geek:
GeoModder wrote:Imagine what you could do if you could add a couple telescopes on the moon to this setup.
Imagine the headaches establishing the accurate timing required... :| But yes, it would be pretty cool.

In the same vein, I'm curious if anything ever came of thoughts about using observations six months apart to do this kind of thing, e.g. the size of the radio telescope is the size of Earth's orbit... at least, to some degree. Probably even more issues with calibrating the various 'scopes, though.

User avatar
Arioch
Site Admin
Posts: 4485
Joined: Sat Mar 05, 2011 4:19 am
Location: San Jose, CA
Contact:

Re: The Astronomy Thread

Post by Arioch »

Mithramuse wrote:I think the Sag A* data is still being processed. Maybe due to there being more dust etc. in the way?
Yeah, the issue was despite being a thousand times closer, Sag A* is a thousand times smaller than M87* and also less active, so it's actually apparently dimmer, and the interactions with nearby stars and its relative closeness meant that it was more of a moving target. From what I gathered reading up on it, they still plan to release a Sag A* image when it's ready, but that may not be for several years, as I think they said they aren't going to do new observations until 2020 due to technical problems. Keeping in mind that the image they just released was derived from observations made two years ago.
Mithramuse wrote:In the same vein, I'm curious if anything ever came of thoughts about using observations six months apart to do this kind of thing, e.g. the size of the radio telescope is the size of Earth's orbit... at least, to some degree. Probably even more issues with calibrating the various 'scopes, though.
I don't think this will work, because this method only works if observations are made at the same time in different locations (and precisely timing them down to the microsecond).

User avatar
Mjolnir
Posts: 452
Joined: Sat Mar 05, 2011 1:24 pm

Re: The Astronomy Thread

Post by Mjolnir »

Arioch wrote:
Mithramuse wrote:I think the Sag A* data is still being processed. Maybe due to there being more dust etc. in the way?
Yeah, the issue was despite being a thousand times closer, Sag A* is a thousand times smaller than M87* and also less active, so it's actually apparently dimmer, and the interactions with nearby stars and its relative closeness meant that it was more of a moving target. From what I gathered reading up on it, they still plan to release a Sag A* image when it's ready, but that may not be for several years, as I think they said they aren't going to do new observations until 2020 due to technical problems. Keeping in mind that the image they just released was derived from observations made two years ago.
Mithramuse wrote:In the same vein, I'm curious if anything ever came of thoughts about using observations six months apart to do this kind of thing, e.g. the size of the radio telescope is the size of Earth's orbit... at least, to some degree. Probably even more issues with calibrating the various 'scopes, though.
I don't think this will work, because this method only works if observations are made at the same time in different locations (and precisely timing them down to the microsecond).
With a very precise and stable timebase and a coherent source, it's possible to use measurements taken over time...it's essentially how synthetic aperture radar works. But there's no coherent source here (and we certainly can't emit it ourselves), and doing it over a 6 month span would be quite a feat.

User avatar
Mjolnir
Posts: 452
Joined: Sat Mar 05, 2011 1:24 pm

Re: The Astronomy Thread

Post by Mjolnir »

GeoModder wrote:Imagine what you could do if you could add a couple telescopes on the moon to this setup.
If you built your telescope at the wrong latitude, it wouldn't ever be able to point at the target. If you happened to build it at just the right latitude, it'd only be able to observe the target for days per month. Those observations would periodically be roughly lined up with Earth, reducing the baseline. Observations taken during the lunar night period would be limited to what can be powered by batteries, those in the day by the relative position of the sun. This is all in addition to the thermal cycling, the dust, and the fact that it'd cost a 1-2 orders of magnitude more to put the telescope on the lunar surface compared to just putting it in orbit, and you'll get a far smaller telescope for a given amount of material due to the need to have it support itself against 1/6th g. The moon is a terrible place for telescopes.

It's easier to put telescopes in orbit, landing telescope parts on the moon and assembling them there vastly drives up cost. Telescopes in orbit can point anywhere in the sky at any time (within limits imposed by the sun, etc), and can be located as far apart as your technology allows you to operate as nodes of an interferometer. Put big radio telescopes at the Earth-Sun L4, L5, and L3 points, and you have 674 times the baseline and nothing in the solar system can block all three nodes from an observation at once. Distance and the ability to directly measure interference from Earth, the Sun, etc are better than any amount of shielding the moon provides (especially a moon industrialized enough to allow construction of big telescopes).

User avatar
GeoModder
Posts: 1038
Joined: Mon Mar 21, 2011 6:31 pm

Re: The Astronomy Thread

Post by GeoModder »

All true, of course.
But alot of things had to line up as well for all those Earth-based telescopes to do their spiel.
IIRC, they had to schedule quite a bit to have 4 days of nice weather in all locations at the same (observation) time(s).
Image

User avatar
Zarya
Posts: 202
Joined: Mon Aug 15, 2016 2:32 am

Re: The Astronomy Thread

Post by Zarya »

Hamburg’s University Observatory provides some more context on what’s surrounding the M87 black hole and on what frequencies the various details can me detected by means of interferometry.

Image

User avatar
icekatze
Posts: 1399
Joined: Sat Mar 05, 2011 8:35 pm
Location: Middle of Nowhere
Contact:

Re: The Astronomy Thread

Post by icekatze »

hi hi

I saw this a few days ago while the forums were down, but I just remembered it. A while back, there was some lengthy discussion about what kind of natural objects could exist in a white dwarf system. This most recent discovery adds another interesting twist.

Heavy metal planet fragment survives destruction from dead star

User avatar
GeoModder
Posts: 1038
Joined: Mon Mar 21, 2011 6:31 pm

Re: The Astronomy Thread

Post by GeoModder »

icekatze wrote:hi hi

I saw this a few days ago while the forums were down, but I just remembered it. A while back, there was some lengthy discussion about what kind of natural objects could exist in a white dwarf system. This most recent discovery adds another interesting twist.

Heavy metal planet fragment survives destruction from dead star
planetesimal? Gosh no, that's some kind of alien habitat wandering aroun' the system! :P
Image

User avatar
icekatze
Posts: 1399
Joined: Sat Mar 05, 2011 8:35 pm
Location: Middle of Nowhere
Contact:

Re: The Astronomy Thread

Post by icekatze »

hi hi

That would be quite a twist! :)

User avatar
Zarya
Posts: 202
Joined: Mon Aug 15, 2016 2:32 am

Re: The Astronomy Thread

Post by Zarya »

"Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun."

Zoomable map of our neighbourhood, based on ESA Gaia data

User avatar
Arioch
Site Admin
Posts: 4485
Joined: Sat Mar 05, 2011 4:19 am
Location: San Jose, CA
Contact:

Re: The Astronomy Thread

Post by Arioch »


User avatar
icekatze
Posts: 1399
Joined: Sat Mar 05, 2011 8:35 pm
Location: Middle of Nowhere
Contact:

Re: The Astronomy Thread

Post by icekatze »

hi hi

Speaking of black hole visualizations, Scott Manley's got an excellent one. It's a 360° youtube video (the first and only I've ever seen.) so you can look around as it goes. It's even better in VR, but still good otherwise.


User avatar
Arioch
Site Admin
Posts: 4485
Joined: Sat Mar 05, 2011 4:19 am
Location: San Jose, CA
Contact:

Re: The Astronomy Thread

Post by Arioch »

Now that's something that Space Engine might be useful for... that effect is not simply done in a normal 3D package.

User avatar
icekatze
Posts: 1399
Joined: Sat Mar 05, 2011 8:35 pm
Location: Middle of Nowhere
Contact:

Re: The Astronomy Thread

Post by icekatze »

hi hi

While it's definitely too early to jump to conclusions, I've got a feeling someone will be sending a probe to Venus in the near future to take a closer look.

Possible Marker of Life Spotted on Venus

User avatar
GeoModder
Posts: 1038
Joined: Mon Mar 21, 2011 6:31 pm

Re: The Astronomy Thread

Post by GeoModder »

icekatze wrote:
Mon Sep 14, 2020 11:38 pm
hi hi

While it's definitely too early to jump to conclusions, I've got a feeling someone will be sending a probe to Venus in the near future to take a closer look.

Possible Marker of Life Spotted on Venus
Here's Putin's chance...
Crash-start a second Venera project.
Image

User avatar
Arioch
Site Admin
Posts: 4485
Joined: Sat Mar 05, 2011 4:19 am
Location: San Jose, CA
Contact:

Re: The Astronomy Thread

Post by Arioch »

Even if NASA decided tomorrow to send new probes to Venus, I think it would take them at least 20 years to actually do it.

Though I'm not sure what kind of probe one would send. They have no idea what they're looking for, and the surface of Venus is not a place where you can just wander around. I think the longest a Venus probe lasted was two hours.

User avatar
Jagged
Posts: 145
Joined: Sat Mar 21, 2020 11:40 am

Re: The Astronomy Thread

Post by Jagged »

Arioch wrote:
Thu Sep 17, 2020 3:43 am
Though I'm not sure what kind of probe one would send. They have no idea what they're looking for, and the surface of Venus is not a place where you can just wander around. I think the longest a Venus probe lasted was two hours.
They are talking about a layer of the atmosphere where the temperature is more like the Bahamas. So quite nice.

Apart from the clouds being mostly sulphuric acid :(

ps: Nice to see a post from you. We were collectively worried you were in trouble due to the fires!

User avatar
Arioch
Site Admin
Posts: 4485
Joined: Sat Mar 05, 2011 4:19 am
Location: San Jose, CA
Contact:

Re: The Astronomy Thread

Post by Arioch »

Jagged wrote:
Thu Sep 17, 2020 8:09 am
Arioch wrote:
Thu Sep 17, 2020 3:43 am
Though I'm not sure what kind of probe one would send. They have no idea what they're looking for, and the surface of Venus is not a place where you can just wander around. I think the longest a Venus probe lasted was two hours.
They are talking about a layer of the atmosphere where the temperature is more like the Bahamas. So quite nice.

Apart from the clouds being mostly sulphuric acid :(
I'd love to see a probe designed to explore Venus' upper atmosphere, but I fear that all they would be able to find are more tantalizing clues rather than an answer. I think that such a discovery would be awesome, but I'm not sure how they would prove it. It's very difficult to prove the existence of atmospheric life with an unmanned probe, and almost impossible to disprove.

The idea of life arising in an atmosphere is interesting but seems unlikely, as atmospheres are not stable environments. Even if an atmosphere is very dense, and there's a zone that conforms to the "goldilocks" parameters for the genesis of life, atmospheres circulate from the surface to extreme altitudes and back again. Any atmospheric organisms will have to be able to withstand dramatic changes in pressure and temperature as the atmospheric currents circulate them from the highest parts of the troposphere down to near the surface. It seems a nearly impossible setting for life to evolve.

I'd love to be proved wrong in this case, (as it would mean that life is possible even in gas giants) but I don't see how such a hypothesis could be proved or disproved with a probe. Even if the probe finds exactly the chemical signatures it's looking for, it can't be proved that such chemicals must be the product of life. People will have to go there to investigate themselves, and that's not an easy ask.
Jagged wrote:
Thu Sep 17, 2020 8:09 am
ps: Nice to see a post from you. We were collectively worried you were in trouble due to the fires!
Thanks. We had a few weird days here with a red sky and the sun being obscured even at midday, but the urban areas of California were not otherwise affected. (Aside from still being under draconian (and unnecessary) lockdown rules that are still in effect here.)

Krulle
Posts: 1413
Joined: Wed May 20, 2015 9:14 am

Re: The Astronomy Thread

Post by Krulle »

Arioch wrote:
Thu Sep 17, 2020 8:47 am
The idea of life arising in an atmosphere is interesting but seems unlikely, as atmospheres are not stable environments. Even if an atmosphere is very dense, and there's a zone that conforms to the "goldilocks" parameters for the genesis of life, atmospheres circulate from the surface to extreme altitudes and back again. Any atmospheric organisms will have to be able to withstand dramatic changes in pressure and temperature as the atmospheric currents circulate them from the highest parts of the troposphere down to near the surface. It seems a nearly impossible setting for life to evolve.
Earth's oceans have similar mechanisms for algae. The water circulates and kills quite a large prtion of the algae when pulling it down. It never resurfaces. But the algae at the habitable layers reproduce fast enough that life continues.
Now a water circulation is different than an air stream, and floatation is more easily achieved in water than in air, but the same general principles may have resulted in a stable environment. The air circulation may even be necessary as it may bring nutrients or trace minerals into the habitable layer (just like the ocean circulation does).

Unless we can actually find it, and observe it in situ, which is nearly impossible, we will continue to speculate.
Arioch wrote:
Thu Sep 17, 2020 8:47 am
Jagged wrote:
Thu Sep 17, 2020 8:09 am
ps: Nice to see a post from you. We were collectively worried you were in trouble due to the fires!
Thanks. We had a few weird days here with a red sky and the sun being obscured even at midday, but the urban areas of California were not otherwise affected. (Aside from still being under draconian (and unnecessary) lockdown rules that are still in effect here.)
Good to read you're alive and well.
Vote for Outsider on TWC: Image
charred steppes, borders of territories: page 59,
jump-map of local stars: page 121, larger map in Loroi: page 118,
System view Leido Crossroads: page 123, after the battle page 195

Post Reply