38 Answered Questions for the topic astrophysics

Astrophysics Space


How do we know for sure that the singularity inside black holes is infinitely dense?

So what causes the black shell around black holes is the fact that light can't escape beyond that point. Since we can't see what is beyond a black hole's event horizon, how do we know for sure... more
Astrophysics Physics Astronomy Space


How can a black hole be electricaly charged if it sucks up all matter (including electrons and protons)

How can a black hole be electricaly charged if it sucks up all matter (including electrons and protons)?thanks!
Astrophysics Physics Astronomy


1. How much stronger is the gravitational force of the Sun on Earth, compared to the gravitational force of the Sun on Pluto?

Full question: How much stronger is the gravitational force of the Sun on Earth, compared to the gravitational force of the Sun on Pluto? Pluto’s semimajor axis is 40 AU, and its mass is 0.002... more
Astrophysics Science Astronomy


What is the theory of relativity in simple terms? - Easy to understand



Is astrology a real science?

Astrology is founded on understanding the positions of the stars, it may seems like a scientific. Believe in astrology varies person to person. I am believing on astrology, it will help us to... more
Astrophysics Science Physics Astronomy


Size of the Moon Question

Let’s say you were to do an experiment using a coin that helps to find the distance from earth to moon through measuring the distance between your eye and the moon with the coin. This will later... more
Astrophysics Physics


Find the velocity of the planet given by description below.

Consider a planet of mass m, moving in a circular orbit of radius r, around a star of mass M. From a = v2/r, the force of gravity and Newton’s second law, find the velocity of the planet. Assume... more
Astrophysics Astronomy


Question about Gravity

J.M.JI understand that two objects pull upon each other with the same gravity, as the gravity equation gives one value for two masses: F = Gm1m2/r2 . However, it sounds absurd to say that a tennis... more


Astronomy astrophysics equation

If the sun expanded to a radius 200 times it's present radius, what would it's average density be in g/cm^3
Astrophysics Science Astronomy


What is the luminosity of this star?

A star observed has a brightness of 0 W·m-2 and has a distance determined to be 6.41×1017 m (16.60 parsecs). Use the equation: B=L/4(pi)d2 to solve this problem.Thank you!!
Astrophysics Physics


Why has the star Rigel moved back and forth on the HR-diagram?

Have a lot of questions. Has it done this more than once? And if it has, has the mass of the star shifted with the fluctuations?Has Rigel already been a red supergiant?How big does the star have to... more
Astrophysics Astronomy


If light takes millions of years to reach us

...are we seeing black holes feeding in the past?
Astrophysics Physics Astronomy


White Holes mistaken for Quasars??

Could a quasar be a white hole? If a black hole pulls in everything including light, while breaking down time as you speed up through the accretion disk till you reach the event horizon, could a... more
Astrophysics Physics


Faster than light

Fou Lu what if you are so tall, that every step you take would be the equivalent of the diameter of our galaxy?Would you need 100 K light years (or even longer) to perform this step, or would it... more
Astrophysics Physics Geography Geology


Earth's mantle and core ?

Has there ever been an attempt to explore the Earth's mantle (either manned/robotic) ? There was an exploration of the Mariana Trench the deepest point of the crust under the pacific ocean, but it... more
Astrophysics Physics Astronomy Redshift


Calculate redshift of a Galaxy using recession velocity and distance

A galaxy is receding away from us with a recession velocity of 100,000 km s^−1. What is the distance to this galaxy? (Don't input the distance, just calculate it.) What is the redshift z of this... more


Flux of sunlight on Earth

The luminosity of the Sun is 4∗10^33 erg s^−1, and its distance to the Earth is 1.5∗10^13 cm.What is the flux of sunlight on the Earth, in units of erg s^−1 s^−1 cm^−2?
Astrophysics Physics Astronomy Gravity


Is it possible for two black holes to collide perfectly?

If two blackholes with exactly the same mass, are traversing the universe on a perfect collision course with no other gravitational force effecting either black hole, what would happen to both... more
Astrophysics Astronomy


What happens to a star when its binary star goes supernova?

Taking into account two binary stars, if relatively close, what would happen when one star goes supernova before the other? Does that binary simply rip apart?
Astrophysics Astronomy Elements


How large does a star need to be for its supernova to produce element 115

How large does a star need to be for its supernova or hypernova / collapsar to produce super heavy elements like 115?Also, how abundant are these stars in the universe?


How is distance measured to far away stars and galaxies?

What I need is an accurate description of the methods used to determine the distance to Andromeda. The Parallax method is for nearby objects as I presume. The red shift method applies, but how do... more


Does a celestial system exhibit a collective magnetic field?

Sol exhibits a magnetic field, most of the planets in orbit around Sol exhibit a magnetic field - strong and weak both. Does the solar system as a whole exhibit a magnetic field? Does the paradigm... more

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