User Abanob Ebrahim

25 votes

4 answers

6k views

Why does the speed of sound decrease at high altitudes although the air density decreases?

asked Sep 12, 2019 at 9:47

23 votes

4 answers

21k views

Explanation for negative specific heat capacities in stars?

thermodynamics astrophysics stars

asked Oct 21, 2014 at 20:15

16 votes

2 answers

6k views

If atoms never "physically" touch each other, then how does matter-antimatter annihilation happen?

particle-physics forces atomic-physics antimatter

asked Aug 10, 2013 at 11:56

14 votes

1 answer

3k views

What is the percentage of stars that are massive enough to end their lives in a supernova?

astrophysics stars supernova stellar-evolution

asked Jul 6, 2014 at 21:29

14 votes

1 answer

4k views

Are the electrons at the centre of the Sun degenerate or not?

thermodynamics astrophysics electrons sun stars

asked Jul 2, 2015 at 18:42

12 votes

2 answers

1k views

Where did the energy released due to gravitational binding energy of the Earth go?

gravity astrophysics earth thermal-radiation geophysics

asked Dec 12, 2014 at 20:22

11 votes

2 answers

489 views

Would a rocky planet orbiting so close to a very hot star eventually vaporize?

homework-and-exercises astrophysics planets thermal-radiation estimation

asked Aug 19, 2015 at 0:07

10 votes

1 answer

760 views

Does matter found at densities of white dwarfs "feel" more like a solid, liquid or gas?

astrophysics density plasma-physics states-of-matter white-dwarfs

asked Oct 15, 2015 at 0:54

10 votes

4 answers

5k views

What is the actual energy content of the Sun?

thermodynamics astrophysics sun stars

asked Oct 21, 2014 at 15:48

8 votes

2 answers

13k views

What is the luminosity of the Milky Way galaxy?

astrophysics stars galaxies observational-astronomy milky-way

asked Nov 26, 2014 at 11:16

8 votes

2 answers

4k views

How much of a galaxy's mass is in stars?

astrophysics stars dark-matter galaxies milky-way

asked Nov 28, 2014 at 2:04

8 votes

5 answers

9k views

What causes damage, kinetic energy or momentum?

newtonian-mechanics energy momentum collision

asked Oct 17, 2014 at 8:24

8 votes

5 answers

9k views

Kinetic energy vs. momentum?

newtonian-mechanics forces energy energy-conservation work

asked Oct 17, 2014 at 23:05

8 votes

1 answer

845 views

Would matter-antimatter annihilation create a fireball or not?

nuclear-physics radiation antimatter

asked Aug 12, 2013 at 22:35

7 votes

2 answers

1k views

What is the percentage of useful energy do we get from matter-antimatter annihilation?

particle-physics energy nuclear-physics antimatter

asked Aug 10, 2013 at 18:17

7 votes

2 answers

2k views

Can the Sun's core be treated as an ideal gas?

thermodynamics astrophysics sun ideal-gas kinetic-theory

asked Jun 30, 2015 at 14:59

7 votes

1 answer

1k views

How could this small nuclear reactor power two jet engines?

nuclear-physics power nuclear-engineering aircraft propulsion

asked Aug 28, 2016 at 21:25

6 votes

2 answers

745 views

How much of the Solar convection zone is completely ionized?

astrophysics atoms stars plasma-physics ionization-energy

asked Oct 7, 2015 at 23:26

6 votes

3 answers

3k views

What does this stellar mass distribution mean?

astrophysics stars galaxies observational-astronomy milky-way

asked Dec 14, 2014 at 0:02

6 votes

2 answers

1k views

How much faster is the fusion we make on earth compared to the fusion that happens in the sun?

energy astrophysics stars fusion

asked Sep 12, 2013 at 7:53

6 votes

1 answer

2k views

How to calculate the kinetic energy of supernova ejecta?

kinematics astrophysics supernova

asked Sep 5, 2014 at 20:27

6 votes

3 answers

547 views

How would normal matter behave under conditions found in the core of the sun?

energy earth sun stars

asked Aug 29, 2014 at 14:11

5 votes

1 answer

356 views

What does a supernova look like at its peak luminosity?

electromagnetic-radiation radiation radioactivity supernova

asked Aug 31, 2014 at 22:25

5 votes

1 answer

2k views

Gravitational binding energy of a white dwarf at Chandrasekhar limit?

gravity astrophysics stars supernova white-dwarfs

asked Sep 2, 2014 at 13:50

5 votes

2 answers

2k views

What is the area of the sky that is covered by the Hubble Ultra Deep Field image?

astronomy galaxies observational-astronomy

asked Dec 16, 2014 at 0:47

5 votes

1 answer

412 views

According to the initial mass function, should there be more brown dwarfs than red dwarfs?

astrophysics stars galaxies observational-astronomy brown-dwarfs

asked Nov 30, 2014 at 0:49

5 votes

1 answer

957 views

Why do neutron stars have solid crusts?

astrophysics material-science stars neutrons neutron-stars

asked Nov 18, 2015 at 21:08

4 votes

2 answers

998 views

Did Usain Bolt really sustain 11 horsepower of exerted power during the 100 m sprint?

newtonian-mechanics energy fluid-dynamics drag power

asked Mar 17, 2019 at 11:33

4 votes

1 answer

175 views

Is a rocket engine most efficient when its velocity is equal to the exhaust velocity?

newtonian-mechanics momentum energy-conservation rocket-science propulsion

asked Apr 7, 2019 at 9:37

4 votes

2 answers

2k views

What is the main thermal energy source for a protostar, the contraction or the deuterium burning energy?

nuclear-physics stars fusion gravitational-collapse

asked Dec 7, 2014 at 1:44

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74 Questions

Why does the speed of sound decrease at high altitudes although the air density decreases?

Explanation for negative specific heat capacities in stars?

If atoms never "physically" touch each other, then how does matter-antimatter annihilation happen?

What is the percentage of stars that are massive enough to end their lives in a supernova?

Are the electrons at the centre of the Sun degenerate or not?

Where did the energy released due to gravitational binding energy of the Earth go?

Would a rocky planet orbiting so close to a very hot star eventually vaporize?

Does matter found at densities of white dwarfs "feel" more like a solid, liquid or gas?

What is the actual energy content of the Sun?

What is the luminosity of the Milky Way galaxy?

How much of a galaxy's mass is in stars?

What causes damage, kinetic energy or momentum?

Kinetic energy vs. momentum?

Would matter-antimatter annihilation create a fireball or not?

What is the percentage of useful energy do we get from matter-antimatter annihilation?

Can the Sun's core be treated as an ideal gas?

How could this small nuclear reactor power two jet engines?

How much of the Solar convection zone is completely ionized?

What does this stellar mass distribution mean?

How much faster is the fusion we make on earth compared to the fusion that happens in the sun?

How to calculate the kinetic energy of supernova ejecta?

How would normal matter behave under conditions found in the core of the sun?

What does a supernova look like at its peak luminosity?

Gravitational binding energy of a white dwarf at Chandrasekhar limit?

What is the area of the sky that is covered by the Hubble Ultra Deep Field image?

According to the initial mass function, should there be more brown dwarfs than red dwarfs?

Why do neutron stars have solid crusts?

Did Usain Bolt really sustain 11 horsepower of exerted power during the 100 m sprint?

Is a rocket engine most efficient when its velocity is equal to the exhaust velocity?

What is the main thermal energy source for a protostar, the contraction or the deuterium burning energy?