swansont

A number of sites have made a similar point about the relatively small area needed for this https://www.businessinsider.com/map-shows-solar-panels-to-power-the-earth-2015-9 There are, of course, other problems one would have to solve (e.g. getting the energy to its destination, storage, etc.)

Stars don’t leave grooves, for there is nothing there that can have grooves. Stars warp spacetime, because they have energy and momentum, but that’s not dark matter.

! Moderator Note 1. Advertising your speculation in another thread is against the rules 2. You have a thread for discussion of time, and you were told “This thread is now the only place where michel123456 may discuss topics related to time and relativity”

I don’t understand the question. This is objective, not subjective. 85% of the matter in the universe https://en.wikipedia.org/wiki/Dark_matter Will you explain what you mean by “grooves left by stars”?

I think flimsy also means flexible. The shoulder normally has a fairly wide range of motion. https://www.ortho.wustl.edu/content/Patient-Care/3138/Services/Shoulder-Elbow/Overview/Shoulder-Instability-Information/The-Anatomy-of-the-Shoulder.aspx

! Moderator Note You should start a new thread to ask this question, rather than hijack this one.

! Moderator Note Yes, it was, and yet you’ve opened a new thread. Don’t do it again. The common theme is James Maxlow's theory of "Earth Expansion Tectonics that you brought up. One thread per topic.

If it has mass, then we can say it’s matter, since that’s one of the properties that define matter. “grooves left by stars”?

I think people are conflating time and time measurement, and I will reiterate: Is there a testable hypothesis here? A model, or evidence?

! Moderator Note Threads merged

What part of GR states this?

Is there a testable hypothesis here? A model, or evidence?

No, it isn’t. The technique is called electromagnetically induced transparency (EIT). The problem here is that the article you read was filtered through the reporter and watered down. Information was omitted. But you won’t notice this if you lack understanding of the physics involved. You just see the buzzwords, and compare them to other buzzwords. It’s like using Cliff Notes for literature. Reading a summary of the book rather than the book itself. There are difference between the experiments, but AFAIK using EIT is not one of the differences. (it would be nice to check, but you need to link to journal papers or the ArXiv preprint to see those details)

You’re just trolling me now.

Not making a dent, am I?

780 nm is the resonance for Rb. The resonance frequency for Rb is ~3.85 x 10^14Hz. (that’s 780 nm) Because the atoms are moving, there is a Doppler shift, that resonance can be higher or lower, depending on that motion. The Doppler shift is up to 500 MHz for a significant fraction of the atoms*, so to be resonant with some of them, you need to be within 500 MHz of 3.85 x 10^14Hz. *the atoms move with speeds that depend on temperature. It’s a distribution of speeds; some move fast, some slow.

Right. The motion of the atom means it will absorb light at a lower frequency than its resonance frequency. For the emitted photons, for every redshifted photon you would get a blueshifted one, on average. The resonance is not at 500 MHz. I explained this. That’s how wide the resonance is - if you are within 500 MHz of the resonance, the photon has the highest chance of absorption.

This reminds me of those folks who insist that their perpetual motion machine will work, and won’t listen to anyone who tells them different. Yes, the doppler shift will be changed slightly. That’s why you need millions of photon scatters to slow an atom to close to zero velocity - the imparted momentum from a single photon is small. p=E/c, and c is a big number. If the cloud is big, light won’t penetrate unless it’s being re-emitted, and that’s in a random direction. Light from random direction won’t cause slowing; there’s no net force being applied It’s usually described in terms of the force, which is in the direction of the laser (looking at a 1-D example). But yes, the emitted light would be slightly more energetic.

A MOT traps neutral atoms, not ions. That’s part of the problem. If you need a few mW/cm^2, and your optics are ~5 cm in diameter, that’s about 40 mW. Six beams, that’s 240 mW. Losses from acousto-optic modulators to tune the laser frequency is a factor of 2. Maybe another factor of 2 for other losses. Basically you need a watt for that. Now you want to scale this up by a factor of 20, which means the area goes up by a factor of 400. You need a 400 watt laser. Huge problem #1 You need 1 meter windows for your vacuum system. Optical-quality flat. If you can find them, they would be super expensive. Problem #2 But it’s probably all for naught, because a 1 meter cloud of atoms will be optically thick, meaning the laser light won’t penetrate, and the re-radiation would cause heating. You would likely not be able to get a 1m cloud of cold atoms to begin the process of forming a BEC.

https://en.wikipedia.org/wiki/Magnetic_trap_(atoms) magnetic trap and magneto-optic trap are two very different things (“optic” meaning photons are involved) But hey, you’ve got your youtube degree, so...whatever.

Sure I can. Physics backs me up. “kinda similar” is not much of an argument; a quadrupole magnetic field + a laser is not “kinda similar” to the capacitor plates Changing the sign does nothing. You still have an unstable equilibrium. If the atom is not at rest at the exact center, it feels a force. And it will never be at rest. In this case it will be attracted to a one of the plates. And this is not the case for either of the electrostatic cases. You don’t have a stable equilibrium.

This won’t work. “Earnshaw's theorem states that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges.” https://en.wikipedia.org/wiki/Earnshaw's_theorem Guesswork is not a replacement for knowledge (studiot expressed a similar sentiment earlier) In this case, if the atom is not at rest at the exact center, it feels a force. And it will never be at rest. The atom will eventually leak out

How would this trap the atoms? I’m looking for a physics answer, not a WAG. Put another way: provide a link to anyone who has trapped atoms like this. I’ve told you this won’t work, and you haven’t detailed how it could work, so why are you asserting that it will? Physics is not magic. Wishing does not make it so. Invoking a few key words is not an incantation that will give you your desired result.

They aren't. The spin of the proton is aligned with the magnetic field in MRI - pointing in that dierection. That doesn't mean the atoms are lined up in a line. Spin is quantized. You can't reduce the spin. You reduce the CoM motion. Spin is quantized. All you can do is change the orientation of the spin. Yes, there is a field, but the force is optical, not magnetic. The function of the field is to Zeeman shift the resonance of the atom. Without the magnetic field you have what is called optical molasses. Cold atoms where the lasers overlap, but not confined. You don't get as many atoms in a molasses, but you can get them colder by letting the cloud expand (in a BEC, the next step is a magnetic trap, and then evaporative cooling)

What does that have to do with its temperature? (which is CoM motion) Depends on what you mean by "lined up" There will always be motion, and some spatial extent. But if you want more confinement, you should use a linear ion trap, which has a stronger restoring force, coupled with laser cooling. At this point I have to wonder if you are doing this deliberately. (after it's been brought to your attention twice in the last few days) A 2-D MOT uses both magnetic fields and lasers. Magnetic traps are not very deep, so they will only confine atoms that are already cold. It would not have a "wider coverage"