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Jan
26
awarded  Nice Answer
Oct
20
comment Why no new quasars?
I'm pretty sure it's because you are using "age" of quasars in the more professional way that you would be used to and I think the OP is using "age" as in the time between when it supposedly formed and now (as opposed to both the time between formation and when it emitted the light we observe now as well as the age of the universe corresponding to the quasar's redshift)
Oct
20
comment Why no new quasars?
@RobJeffries Yeah, I gave you the +1 on both your quasar answers, but here I still think the was a misinterpretation. I think the hypothesis was posed as an attempt for the OP to answer their own question. The way I read it (and whether I'm right or wrong, your answer is still fitting) was as "why does there not appear to be any quasars that formed more recently than ~13 Gya? Is it perhaps because circumstances made all quasar activity only happen within 1 Gy of the Big Bang?". While your answer covers that by listing some that formed later, the misinterpretation remains.
Oct
20
comment What exactly is light?
In physics, light is $A_\mu$. Okay, it's a bit more than that, but once you have $A_\mu$, you inevitably have light
Oct
20
comment Why no new quasars?
Not to critique this great answer (really, I do like it), but I think by "new quasars" the OP didn't mean that they look young when we see them but ones that appear to have formed within, say, the last billion years. A quasar with a redshift of 8 may be a billion years or less old when it emitted the light we are observing, but if it's still around now, it's an old fuddy duddy quasar.
Oct
4
answered Meaning of angles on Feynman diagram
Oct
1
comment Meaning of angles on Feynman diagram
@KyleOman I would, but I'm literally on my way out the door. I rushed to comment it for others. That's all the time I have
Oct
1
comment If a vehicle (bus, train) rapidly stops (or accelerates, or turns), why don't our hair or clothes move from the inertial force?
I see this happening all the time. The bus stops suddenly, loose clothing, necklaces, the fabric handles on the top bar in the bus, etc. All sway forwards. I don't know why you don't see it happening (do you live somewhere where people wear unusually tight clothes?) but I assure you it happens just as you'd expect
Oct
1
comment Lorentz force on current
Neighbouring charges can affect each other. But the generation of a magnetic field due to motion is a phenomenon of relativity. Relative to the charge itself, it is at rest in its own frame, so it does not see any magnetic field generated by it.
Oct
1
comment Lorentz force on current
note that the magnetic field generated by a moving charge does not directly affect the charge itself. It can indirectly affect the charge, but a charge won't start spiraling due to the magnetic field it generates.
Oct
1
comment Given Newton's 3rd Law, how is a sea-pumped hydro jetpack possible?
It matters where the pump is. The pump will experience the downward force to counteract the rider's upward force. Usually the pump is near the end of the hose; floating in the water. Everything directly attached to the rider only accelerates the water downwards, thus accelerating the rider upwards. Only the pump (and technically the hose) accelerates the water upwards
Oct
1
revised Potential difference between 2 points in a loop containing changing magnetic field = 0?
added 86 characters in body
Oct
1
comment How fast does space/time travel?
Welcome to Physics.SE! Please note that we expect a modicum of prior effort behind the questions posted here. Since the answer to that question can be found by literally typing "speed of expansion of space" into Google (albeit the first number it gives you is slightly off), this doesn't reflect as showing prior effort.
Oct
1
answered Potential difference between 2 points in a loop containing changing magnetic field = 0?
Oct
1
comment What is the equation of motion for multiple simultaneous pressure waves in a medium? (In the context of stimulated Brillouin scattering)
Welcome to Physics.SE! Let me just say this is a great question.
Oct
1
comment Does increasing pressure, increase gravity?
I'm just being humourous. Your answer is fine.
Oct
1
comment Does increasing pressure, increase gravity?
That's right kiddies, hot gas weighs more than cold gas. Knowing that, it shouldn't be so surprising that we use it to lift hot air balloons.
Oct
1
comment Velocity of photon when changing direction
"Change direction" is more ambiguous than "turn". Wait no it isn't. Taken literally, changing direction means the magnitude of the velocity vector is constant. Which means if it starts as non-zero, it will always be non-zero
Oct
1
comment Does increasing pressure, increase gravity?
@CoilKid Oh, I see. Well, without gravity there would be not objects capable of having an atmosphere, so I must, therefore, agree with you
Oct
1
comment Does increasing pressure, increase gravity?
Addressing the post, however, dark matter is not created by a negative pressure in the gravity field or anything along those lines. Negative pressure doesn't give rise to dark energy; dark energy has negative pressure. This pressure is not the same thing as atmospheric pressure.