https://www.reddit.com/r/askscience/comments/xe2r2e/ask_anything_wednesday_physics_astronomy_earth/
created by AutoModerator on 14/09/2022 at 14:00 UTC
36 upvotes, 18 top-level comments (showing 18)
Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on **Physics, Astronomy, Earth and Planetary Science**
Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".
Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.
Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here[1]. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.
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Past AskAnythingWednesday posts can be found here[3]. Ask away!
Comment by StructureOrAgency at 14/09/2022 at 14:52 UTC
8 upvotes, 2 direct replies
If you were to be transported to intergalactic space, would you be able to see anything using just human vision?
Comment by m4gpi at 14/09/2022 at 15:56 UTC
6 upvotes, 1 direct replies
I asked this before in a post, but I’ll simplify it: how are lightning strikes detected and reported by technology (say, in a weather app)? I ask because sometimes I’ll get a notification that there was a strike within a close distance to my house (some hundreds of feet) but I don’t think it actually touched down. And given that lightning often moves laterally, are the strikes geo-located from the cloud, or from the ground?
Comment by spudfolio at 14/09/2022 at 16:31 UTC
4 upvotes, 2 direct replies
How does the physics of air on the smaller scale of insects affect their aerodynamics and flight mechanisms differently than birds or planes?
Comment by ArtDouce at 14/09/2022 at 14:39 UTC
3 upvotes, 1 direct replies
Given the limitations of materials and the fact that space isn't actually empty (~1 to as much as 1,000 H atoms per cm^3), how fast would it be possible for a large object (say big enough to carry a reasonable number of people and supplies) to travel through space?
Note our current highest temp material is good to ~4,000 C.
For this question, I think its fair to assume we could possibly double this.
I've read assertions that its C/10, but can't quite work out the math to prove or disprove it.
Comment by Sex_And_Candy_Here at 14/09/2022 at 18:49 UTC
3 upvotes, 1 direct replies
I'm just generally confused about the details of relativity. I've invented a scenario to explain my confusion. I made a (bad) diagram to explain my confusion[1]. Basically, a car moving at 0.5c shoots a burst of light at a target, but between the target and the car is a trap door that will close in just over 1 second (timer is in the same inertial frame as the target). The trapdoor is 1.5 light seconds away from the car. Does the light beam hit the target or is it blocked by the door? From the inertial reference frame of the target, the light will take 1.5 seconds to reach the door and so will be blocked, and a clock on the car will be slow. I get that part. But from the car's inertial reference frame, the target and door are moving closer at 0.5c, and the light will hit the target in 1 second (before the door shuts). This would be resolvable by having the timer on the target count fast relative to the car's clock, but shouldn't the timer count slow relative to the car, since from the car's reference frame, the timer is moving and should experience time slower? Does the trap door actually block the light? Why does time slow down for the car but not the target? I understand that the twins paradox is caused by acceleration, but there isn't any acceleration here.
Comment by yoshhash at 14/09/2022 at 16:24 UTC
2 upvotes, 1 direct replies
When you are just trying to get a predictable amount of heat into a closed system, does a 100 Watt incandescent light bulb input an equal amount of heat energy as a 100 Watt heater?
Comment by Quixotixtoo at 14/09/2022 at 17:17 UTC
2 upvotes, 2 direct replies
For a rocket powered by a fuel with a given specific impulse, is there a maximum size (mass) planet from which the rocket could escape?
My question is a theoretical question, not a practical one. So ignore things like material strength limits for rocket housings, atmospheric drag, etc. Also, I understand that a black hole is inescapable. But do the equations for thrust, escape velocity, etc, impose a much lower limit for a given specific impulse fuel?
Comment by f_d at 14/09/2022 at 19:35 UTC
2 upvotes, 1 direct replies
The Webb telescope pictures of the distant sky give me an unusual sense of depth compared with previous space photography. Having the extra layer of distant but clearly resolved galaxies seems to help resolve the 3D structure of the universe more clearly, with tendrils of galaxies stretching off into the distance. Is this an accurate interpretation? Is it more prominent with Webb than with previous telescopes?
When we look at astronomy photos that stretch back to the early days of the universe, how exactly does our perspective relate to the age of the light and the expansion of the universe? In photos, does a 13-billion-year-old redshifted galaxy appear in the position of an object 13 billion light years away, or do relativity and the expansion of the universe make it look closer or farther on top of the travel time? It's easy to understand that the distant galaxy is now a lot farther away from us than when its light originally started traveling, but what else happens to inform our perspective of all the incoming light before it finally arrives in the telescope?
Comment by Rami_pro at 14/09/2022 at 21:17 UTC
2 upvotes, 4 direct replies
When i see pictures of different nebula from hubble or jwst, would it look the same if i was looking at them with my own eyes from up close? Or are the images edited to show the different gases and dust?
Comment by NotAQuietKid at 14/09/2022 at 14:19 UTC
2 upvotes, 2 direct replies
suggest a Investigatory Reasearch topic that we can use (9th grade science)
Comment by lowaltflier at 14/09/2022 at 17:22 UTC
1 upvotes, 1 direct replies
Are there any theories of what happened before the Big Bang? Are there alternate theories to the Big Bang?
Comment by uaPythonX at 14/09/2022 at 18:12 UTC
1 upvotes, 0 direct replies
Have there been any observations or other evidence of over-Chandrasekhar limit White Dwarves that have such a short rotation period that they will eventually either go Supernova or collapse further to a Neutron Star state as their rotation slows down due to the loss of angular momentum?
Comment by RobRows101 at 14/09/2022 at 19:05 UTC
1 upvotes, 2 direct replies
I understand the concept of looking at the light from the oldest known galaxy gz-11 and the time it takes to reach us is 13 or so billion years and therefore we are looking into the past. Are we looking back toward the location of where the big bang happened? Is this how to think about the big bang? Im struggling to understand our position in the universe when it comes to looking back in time. In my mind gz11 can't possibly be 13 billion light years away, because surely the event isn't that far away from us in light years. We were also part of the big bang.
If gz11 also had a telescope on it looking at us, would it see us in our present state or us 13 billion years ago?
I appreciate I'm finding it very hard to even articulate this issue. I hope someone understands roughly what I'm getting at!
Comment by SvenAERTS at 14/09/2022 at 19:27 UTC
1 upvotes, 0 direct replies
Thy
as per https://en.wikipedia.org/wiki/Talk:Euler%27s%5C_Disk#Isn%27t%5C_Euler%27s%5C_Disk%5C_used%5C_to%5C_explain%5C_the%5C_plane%2C%5C_the%5C_movement%5C_and%5C_inclination%5C_of%5C_the%5C_Moon%5C_around%5C_the%5C_Earth%3F
Comment by Infernoraptor at 14/09/2022 at 19:30 UTC
1 upvotes, 1 direct replies
Tjis msy be a dumb question but, do we know what on-the-surface deposits look like for valuable ore-bearing minerals or had we basically mined all of them before we thought to study them?
I doubt they'd look too different than when underground, but I'm curious how the biosphere might react to some of these.
Comment by aaaanoon at 14/09/2022 at 19:57 UTC
1 upvotes, 1 direct replies
What is the commonly understood meaning of the term 'Universe' amongst physicists?
'all that is, has been and can be' is a broad summary that I have used. The broadest of definitions to describe everything that is known to exist. It's important to note -the scope of the definition expands to include anything new that is discovered.
Terms like 'multi-verse' and 'parallel universe' are used alot but are contradictory if the classical definition is used.
Comment by ThisFingGuy at 14/09/2022 at 20:30 UTC
1 upvotes, 2 direct replies
How fast is the universe expanding at its furthest point? I know the rate is different based on how far away something is from us and that it is some speed greater than light. I've heard c^3, is that accurate?
Comment by NikStalwart at 17/09/2022 at 08:16 UTC
1 upvotes, 1 direct replies
Perhaps this is a nebulous question, but here goes: what sci-fi things* could we make for sure**, but just don't know how to, yet?
The best historical example of something like this are videocalls from the perspective of 1940-1960s-era society. Videocalls were a staple of the science fiction of the time. We had already invented television and telephones, so it was conceivable that sooner or later, we'd be able to combine the two. Lo and behold, it is 2022 and everyone has a pocket telephone, television and videocall device—all in the same box.
So, from our perspective, what is the equivalent of a video call? Something that we know with 99.97% certainty is possible, but we don't have the intermediate steps for?
I would imagine that the two obvious candidates are fusion power and AGI. Similarly, I would think that something like wormhole travel or folding spacetime to bypass the cosmic speed limit are two things which don't qualify because we don't know with a high degree of certainty that the underlying techniques are even possible. So, what else is there?
