Category Archives: Physics

What is the Critical Mass at Which a Star Becomes a Black Hole?

Question:  How do you calculate the critical mass for a star to become a black hole? I’m an undergraduate Math major, and this is my senior thesis and I really have no idea where to start.  – Lauren Answer:  An … Continue reading

Posted in Black Holes, Physics, Stars | Tagged , | Leave a comment

Can Brain Waves be Detected by a Satellite Radio Telescope Array?

Question:  I have a question that pertains both to space and life on the ground.  It is my theory that, in essence, the U.S. communications and spy satellite network could be used as a massive (about 13 billion square-mile) radio … Continue reading

Posted in Physics, Radio Astronomy, Telescopes, Uncategorized | Tagged , | Leave a comment

Have We Ever Received Radio Signals From Space?

Question:  Hello I was wondering have we ever received any radio signals from space? What I’m trying to ask has earth ever received a message from space?  – Brandon Answer:  Well, in fact, all objects in the universe that emit … Continue reading

Posted in Physics, Radio Astronomy | Tagged , | Leave a comment

Is Kepler’s Second Law Wrong?

Question:  I am suspicious about Kepler’s area law.  Such law should not exist.  I am finding “the cycling velocity of the celestial body is constant and not the swept out area”.  How to prove that area 1/2*r*Vp=constant?  In addition I … Continue reading

Posted in Physics, Solar System | Tagged , | Leave a comment

What is the Difference Between the Redness of an Object and its Redshift?

Question:  What is the difference between Doppler shift of light and Natural light spectra (blue for young and red for old) with respect to stars and galaxies? How does astronomers differentiate between Doppler shift and Natural light spectra of deep … Continue reading

Posted in Cosmic Distances, Cosmology, Physics | Tagged , , | Leave a comment

How Do Pulsars Produce Pulses?

Question:  Hi ! I see this question some years ago on some site ( Astronomy are build with “somes”, are they ? LOL ), but answers ( none of them ) satisfies my curiosity. The question is about Pulsars. If … Continue reading

Tagged Leave a comment

How Does Light Travel Like a Wave?

Question:  I have a question regarding the speed of light from a reader on my website. I wonder if you could help answer it? So here’s a thought that just occurred to me. Light moves at C. In a year, … Continue reading

Tagged 1 Comment

The Earth-Moon Spin-Orbit Resonance

Question:  For being a chunk of Earth’s primordial matter the Moon is quite an amazing stellar feat…it orbits synchronously about the earth with an axis spin velocity 1/100 that of Earth and counterclockwise orbit equal in period as that of … Continue reading

Posted in Physics, Planets, Solar System | Tagged , , , | Leave a comment

What Would Happen to the Orbit of the Moon if it Were Twice as Massive?

Question:  If the Moon was twice more massive and if it had the same orbital speed, would its orbit change?  Further from Earth (because of the centrifugal force), or closer to Earth (because of the gravitational force) or the same … Continue reading

Posted in Physics, Solar System | Tagged | Leave a comment

What Causes Seasons on Earth?

Question:  Hi am just curious about something and I need your help. So well all know it has different seasons in the year, but the thing am curious about it why does the climate change?. What I mean is it … Continue reading

Tagged , Leave a comment