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Top Questions

73 votes
2 answers
6k views

Why doesn't a nucleus-like body made up of just neutrons exist?

15 votes
9 answers
9k views

Can a balloon start from Earth and fly to the Moon, using Helium for lift to the top of the atmosphere and then as propellant?

23 votes
7 answers
3k views

Is special relativity relevant to understand nuclear bombs?

17 votes
5 answers
6k views

How does it make sense for the universe to have started from a big bang?

32 votes
5 answers
7k views

Am I in a superposition?

31 votes
3 answers
4k views

Why aren't Runge-Kutta methods used for molecular dynamics simulations?

31 votes
3 answers
3k views

Why are there three bright spots in the first picture of Sagittarius A*?

12 votes
5 answers
3k views

Why would black hole rip me apart?

23 votes
4 answers
5k views

Why are magnetic monopoles "incompatible" with quantum mechanics?

17 votes
5 answers
3k views

Wouldn't the cosmic background radiation (CMB) produce drag and thus create a preferential inertial frame?

14 votes
6 answers
4k views

Would you run faster on Mars?

18 votes
7 answers
2k views

What makes energy "the" conserved quantity associated with temporal translation symmetry?

8 votes
5 answers
1k views

Can positrons attract electrons? [duplicate]

16 votes
3 answers
4k views

How can the universe be hot or dense in the first moments after the big bang when it has no matter?

21 votes
3 answers
2k views

Equations of motion only have a solution for very specific initial conditions

9 votes
3 answers
3k views

Can Jupiter turn into a star if it radiated off enough heat?

8 votes
10 answers
859 views

Why is Power = Voltage $\times$ Current?

14 votes
3 answers
3k views

Is it possible to convert gravitational energy directly into electrical energy?

11 votes
4 answers
2k views

Special Relativity: If speed of light is constant, then why measured lengths and times aren't changing in the same way? [duplicate]

12 votes
3 answers
3k views

How are anomalies possible?

4 votes
5 answers
964 views

If particles are also waves cant we invert them by making it reflect off a fixed boundary?

10 votes
2 answers
2k views

Why were sparks created in Rutherford's alpha particle scattering experiment?

11 votes
3 answers
3k views

What happens when the universe runs out of fuel?

10 votes
2 answers
2k views

Alternate sky colors?

14 votes
3 answers
1k views

What is the fundamental reason for the imaginary unit in Heisenberg's commutator relations?

8 votes
2 answers
1k views

Failure of Newton's corpuscular theory and success of photon theory of light

5 votes
4 answers
759 views

Where does gravity come from?

10 votes
3 answers
1k views

Why is Dirac's Phase Operator Non-Hermitian?

2 votes
5 answers
593 views

Why relativistic mass of a body increases with its speed? [duplicate]

4 votes
3 answers
2k views

Will a light come back within finite years?

9 votes
3 answers
1k views

Physics of the convection oven

6 votes
6 answers
787 views

Energy to momentum

6 votes
2 answers
958 views

Why is Equation of State of Photon gas different from the Equation of State of Boson gas?

12 votes
2 answers
2k views

Why does an Alcubierre drive, travelling FTL, violate causality, if the universe expanding FTL doesn't?

6 votes
4 answers
385 views

Does the Carnot efficiency apply to photoelectric conversion?

9 votes
1 answer
700 views

Intuition behind the differential equation for forced oscillations

8 votes
1 answer
1k views

Why did the quark epoch occur earlier than the lepton epoch?

6 votes
2 answers
1k views

How can a pulsar slow down?

7 votes
1 answer
718 views

Why do we need to make sense of QED in continuous spacetime anyway?

6 votes
4 answers
516 views

What frequency of cord shaking maintains the same vertical motion for a point on the cord after increasing the wave speed on the cord?

4 votes
3 answers
1k views

Is the concept of bicolored gluons mathematically precise/meaningful? Please explain

5 votes
4 answers
213 views

Why is torque defined as $\vec{r} \times F$?

5 votes
4 answers
1k views

Does a receiving antenna radiate the power received?

4 votes
5 answers
846 views

Why is there no temperature difference in the Joule expansion experiment?

3 votes
2 answers
884 views

Why do elements, as they have more protons, need a higher amount of neutrons to stabilise them? [duplicate]

9 votes
1 answer
1k views

How is it that we are still able to talk about the speeds of other galaxies, distances and times across the universe, etc despite GR?

5 votes
3 answers
1k views

Where does all the energy in black holes go?

6 votes
1 answer
990 views

How is a Bose-Einstein condensate produced from sodium atoms that do not have an integer spin?


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