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mfb- t1_jee3ou8 wrote
Reply to comment by TrIpmasterforce in A group of college students are sending a rover the size of a shoebox to the moon by speckz
Not on that rocket, and not in May (and not in 2023). Not sure what the author got mixed up there.
Artemis II is planned to send humans around the Moon and Artemis III is a planned Moon landing.
mfb- t1_jee35a1 wrote
Reply to comment by Select-Owl-8322 in A group of college students are sending a rover the size of a shoebox to the moon by speckz
In May!
The only Moon-related launch scheduled for May (sort of) is Vulcan's maiden flight with the Peregrine lander (and two Earth orbit satellites for Amazon) as main payload.
No humans on board obviously. Vulcan is never expected to fly people to the Moon.
mfb- t1_jedv127 wrote
Reply to comment by DarkTheImmortal in ELi5 If the universe is expanding, what is it expanding into? by cashmoneyhash
Yes, if the universe is finite then its volume increases. So what? Doesn't stop OP's question from being relevant, with the answer still being "it's not expanding into anything".
mfb- t1_jedt2t4 wrote
Reply to comment by xnyer in ELi5 If the universe is expanding, what is it expanding into? by cashmoneyhash
> The universe is already infinite
We don't know if it is.
mfb- t1_jedt1iu wrote
Reply to comment by DarkTheImmortal in ELi5 If the universe is expanding, what is it expanding into? by cashmoneyhash
> The universe is already infinite
We don't know if it is.
> This can ONLY happen when infinity is involved.
No. The universe could be finite, and still expand.
mfb- t1_jednl5h wrote
Reply to comment by wheatgivesmeshits in eli5 What does “indicted” mean? by jcw10489
There is no precedent for this specific case, so I wouldn't extrapolate from past conviction rates anyway.
mfb- t1_jedjlbs wrote
Reply to Do people with above-average visual acuity benefit from low-magnification optical aids (binoculars & scopes in the 2x range or lower) the same way average or poorer-sighted people do? by screwyoushadowban
Any binocular worth spending money on will give you a magnification of a factor 2 even with 20/10 vision, so better vision without binoculars transfers to better vision with one. With the caveat that using binoculars and glasses together can be tricky, but that's not specific to the ideal vision strength. A really cheap binocular might be worse.
mfb- t1_je8wf3w wrote
Reply to comment by Weed_O_Whirler in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
Permanent magnets have a saturation magnetization. Trying to apply stronger fields doesn't magnetize the material more, and if you drop the external field then the field of the magnet decreases, too. In practice you get around 1.3 T for neodymium magnets, theoretical values might be slightly higher. This publication calculates 1.32 to 1.38 T.
The size of the magnet doesn't matter, you just scale up everything linearly in space and the field gets larger but not stronger.
mfb- t1_je89fs0 wrote
Reply to comment by Bandersnooty in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
> What I'm asking is whether or not it is possible that there is a form of energy so far undiscovered [...] that can travel faster than light.
That is possible, but it looks very unlikely. And it's not related to entanglement.
> that registers at a quark or subquark level
That part doesn't make sense.
> Light is the current known standard by which to measure speed, but photons are comprised of "bundles" in the electromagnetic field being transferred super fast from one point in the field to another point in the field.
No, the speed of causality is a far more fundamental concept. Light travels at that speed, and we call it "speed of light" for historical reasons, but the speed limit is much more general than light.
> "The field" itself is what I would like to know more about and understand its role in energy transfer.
The electromagnetic field? That's again not a question about entanglement.
> Quarks are theoretical and considered so bc there isnt concrete physical evidence for them
Are you commenting from the 1950s? That's a time where such a statement would have been reasonable. We have studied quarks routinely for decades now.
> its entirely possible that there are even smaller units than quarks that are undetectable due to limits in current technology.
That's unlikely but we cannot fully rule it out. But again, this has nothing to do with anything else in your comment.
mfb- t1_je88q1o wrote
Reply to comment by [deleted] in Can gravitation lensing massively shift the apparent location of stars? by IPv6Guy
There are no "absolute positions" anyway.
mfb- t1_je7szo5 wrote
Reply to comment by someon332 in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
It's like trying to reach last Monday. In which direction would you walk? Similarly, avoiding the singularity is as impossible as trying to avoid reaching the next Sunday.
mfb- t1_je7sqpn wrote
Reply to comment by Bandersnooty in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
The speed of light as speed limit for information transfer has nothing to do with the size of particles. You cannot transfer information faster than light, no matter which particles you use and no matter which particles exist, entanglement doesn't change that.
mfb- t1_je7sbd5 wrote
Reply to comment by MrDeltoit in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
He is a crackpot.
> Is it theoretically possible?
No.
mfb- t1_je7s8lg wrote
Reply to comment by nogoodusernameslft99 in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
It has some connection to real physics. Some parts are made up for the story, but you can clearly see that the writers listened to physicists in many places.
mfb- t1_je7r7om wrote
Reply to comment by Weed_O_Whirler in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
A neodymium magnet won't produce a field stronger than 1-2 T. We have MRI machines that are significantly stronger than that, and they don't kill their patients.
mfb- t1_je7qygw wrote
The amount of light that gets deflected by more than a tiny fraction of a degree is negligible, and a measurable deflection needs the lensing of other galaxies and good telescopes to notice it at all. All the stars you see with the naked eye are where you see them.
mfb- t1_je7qe4h wrote
More particles and more interactions - QED is only electromagnetism, which is the easiest interaction to work with. The strong and weak interaction are more complicated, and then you also have to add the Higgs mechanism.
mfb- t1_je7pt7h wrote
Reply to I remember hearing during the hype leading up to the JWST launch that it would take roughly six months to a year to complete the first pass of an updated CMB map. How are we doing on that? by yofomojojo
JWST doesn't measure in the wavelength range of the CMB, so I'm not sure what you heard but it doesn't sound right. Here are three things that might be related:
JWST needed about half a year from launch to the first science images. That time was spent unfolding the telescope (~1 month) and calibrating it and its instruments.
JWST can only observe targets in a ring around the Sun/Earth direction, in the worst case you need to wait almost half a year until your target is in view.
[Planck](https://en.wikipedia.org/wiki/Planck_(spacecraft)) needed ~9 month to make a full-sky map of the CMB in 2009-2010 based on the way it scanned the sky and again the issue that you cannot measure too close to the Sun.
mfb- t1_je5caed wrote
Reply to comment by phlpnow in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
> Clearly you don't have two angles to do this
For nearby stars you do. You measure their position in the sky, and then you measure again 6 months later when Earth is on the opposite side of the Sun. Twice the Sun/Earth distance is a short baseline compared to the distance to stars but angle measurements are precise. Stars move relative to the Sun so you need at least three measurements, and in practice you try to get even more to reduce uncertainties.
That method works up to ~10,000 light years or so (with a somewhat lower precision for distances beyond that). For stars farther away you use the cosmic distance ladder, which uses stars with well-known behavior nearby to determine the distance of equivalent stars farther away. Objects next to these can then be used to estimate the distance of even farther objects with the same method.
mfb- t1_je5bjqa wrote
Reply to comment by Muhabba in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
That's the natural arrangement of a system with non-zero angular momentum where objects collide with each over time: A disk is the configuration you get after everything not in the disk collided with other particles. Planetary rings are pretty flat for the same reason: Here is a video explaining the concept.
mfb- t1_je5b6p6 wrote
Reply to comment by tmoore82 in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
> Does an atom displace spacetime?
No.
> Is spacetime between the nucleus and the electrons?
There is space between them, i.e. they have some distance to each other (ignoring some technical details from quantum mechanics). That applies to all times, so you could say that there is "spacetime between them", but I don't think that's a useful way to view it. The same applies to all extended objects, including nuclei.
> Or is spacetime right beside me when I'm sitting in my living room?
Is "beside you" a place? Yes. That's part of space, which is a part of spacetime.
mfb- t1_je4eu6y wrote
Reply to comment by [deleted] in How does an ideal vacuum have a dielectric breakdown voltage of 10^12 MV/m? If there is nothing there, then how can electricity pass through it? by skovalen
In practice you focus beams of electromagnetic radiation to collide with each other. You can't reach fields anywhere close to the Schwinger limit with charged walls, so again, this has nothing to do with walls.
mfb- t1_je40l8w wrote
Reply to comment by [deleted] in How does an ideal vacuum have a dielectric breakdown voltage of 10^12 MV/m? If there is nothing there, then how can electricity pass through it? by skovalen
OP is asking about the Schwinger limit. This has nothing to do with walls.
mfb- t1_je40is2 wrote
Reply to comment by [deleted] in How does an ideal vacuum have a dielectric breakdown voltage of 10^12 MV/m? If there is nothing there, then how can electricity pass through it? by skovalen
This is just a popular science myth. It's not an actual physical process.
mfb- t1_jefh2nx wrote
Reply to comment by kompootor in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator
I'm not sure how you got the dipole moment. The uniform component of Earth's magnetic field is only changing the energy of the arrangement, the force comes from the inhomogeneity. As an order of magnitude estimate, the force will be F = B_1 V B_E / (R_E mu_0) with B_1 and B_E being the two magnetic fields, V being the volume of the steel block and R_E being the radius of Earth (as scale of the variation of Earth's magnetic field). mu_0 is the vacuum permeability. Coincidentally, it's comparable to the number you got, 10^(-5) N.
If we don't divide by the radius of Earth we get a (sort of) potential energy, which is tens of joule. Completely negligible compared to hundreds of gigajoule of kinetic energy.