Category Archives: Physics

Why Do High Tides Happen Both on the Side of the Earth Facing Toward and Away from the Moon?

Question: During new moon, moon is between earth and sun. The spring tide then occurs. The height of high tide is higher. But on right side of image why is water having high tide. As there is no force pulling … Continue reading

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Do We Observe the Sunrise Six Minutes After it Actually Occurs?

Question: We know sunlight takes about 8 min to reach earth. So we see sunrise 8 min later. Also we see sunrise 2 min earlier due to atmospheric refraction. Does it mean that we see sunrise after about 6 min … Continue reading

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Do the Stars Seem to Move in the Night Sky Because of the Earth’s Rotation?

Question: Do stars seem to move in the night sky because of the Earth’s rotation?  — Selena Answer: Exactly.  As the Earth rotates on its axis it makes it look like the stars are moving through the night sky.  Also, … Continue reading

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How Old is the Light from the Stars that we see in the Night Sky?

Question: One of the questions that always has remained unanswered to me is the following.  When we see the stars on naked eyes or by telescopes, those are obviously many light years away from us, but do we see them … Continue reading

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Why Are Ocean Tides on Earth Larger During a Full Moon?

Question: If I am correct in assuming that the moon’s apparent waxing and waning are merely the effects of the amount of shadow it is in, and it is always the same size, why are the effects of a full … Continue reading

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Is There a Place Where One Can See Daily Radio Images of the Sun?

Question: Is there a place that posts daily images of the Sun in a radio frequency, perhaps 21 cm, something like SOHO does for shorter wavelengths?  — Donna Answer: Unfortunately, I am not aware of a source for regular radio … Continue reading

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Which Planet Orbits our Sun the Fastest?

Question: Which planet in our solar system is orbiting the sun at the fastest speed?  — Mike Answer: Mercury is the winner at an orbital speed of about 47.87 km/s (107,082 miles per hour), which is a period of about … Continue reading

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Does the Coriolis Effect From the Milky Way Rotation Influence the Orbits of Planets in our Solar System?

Question: I read that our solar system orbits the center of the Milky Way Galaxy and am wondering if orbital direction of the planets was initially influenced by the Coriolis effect.  — Jack Answer: Two comments to your question.  First, … Continue reading

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How to Calculate Heliocentric Julian Date from a Given Julian Date and Object RA/Dec

Question: What is the algorithm for calculating Heliocentric Julian date from a given Julian date and object RA/Dec?  I would like this for a variable star application I’m writing.  — James Answer: I would start with the online calculator provided … Continue reading

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How Many Earths Can Fit in the Volume of the Milky Way?

Question: How many earths can fit in one galaxy and if the earth were about the size of galaxy how many planets, moons, etc. would be able to fit on earth.  — Xondra Answer: To answer this question you need … Continue reading

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