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tionis
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Would a nearby Gamma Ray Burst (GRB) cause the Sun to cast a shadow on Earth if it were to shine from behind it?
mfb said:To a very good approximation, indeed.
What do you know about the relative size of sun and earth?
UltrafastPED said:Yes, but what size is the shadow of the sun on the surface of the earth?
Chronos said:As a plasma ball, the sun is a very efficient gamma ray shield. The sun moves across the sky an apparent 60 arc minutes per day. It's apparent diameter is about 30 arc minutes. You should be able to figure out from this about how long the sun could shield us from a GRB [a point source] occurring on a line of sight behind the sun.
How big is the Earth in arc minutes? How much of the Earth does that cover...?tionis said:The Sun is bigger but farther, and Chronos said it is 30 arc minutes in diameter.
30 arc minutes?
Gamma ray bursts aren't very bright visibly. So it wouldn't be much of a "shadow"Ok. So what I basically want to know is if the visible luminosity of a GRB is powerful enough to cause the Sun to cast a shadow on Earth.
Yes, and much brighter than a GRB. But still not much of a "shadow".I guess a supernova could do it, too, right
russ_watters said:How big is the Earth in arc minutes? How much of the Earth does that cover...?
It's a trick question; That doesn't translate into a size on earth. For this situation, the angular diameter of the sun doesn't matter, only the fact that its real diameter is much larger than earth. All of Earth will be in "shadow"tionis said:I don't know..
No. Those events are nowhere close to as bright as the sun (er - perhaps a GRB from within our galaxy would be, but they are rare events and so far are only seen from far away). It depends on distance of course, but a supernova in our galaxy might shine as brightly as Venus.I'm trying to picture what the sky would look like if the Sun were to 'eclipse' a GRB or a supernova. It seems that the glare from either of those two events could overwhelm the visible brightness of the Sun by several orders of magnitude, no?
Not in the normal sense of the word, no.Are you saying the Sun wouldn't cast any shadow on the Earth with that much light in the background?
The shadow of the Sun refers to the area of space behind the Sun where sunlight is blocked by the Sun itself. This shadow is constantly moving as the Earth orbits the Sun, and it is also affected by the tilt of the Earth's axis.
The shadow of the Sun has a significant impact on Earth's climate and weather patterns. As the Earth moves through the shadow, the amount of sunlight reaching the planet changes, leading to seasonal changes and variations in temperature. The shadow also plays a role in eclipses, when the Moon passes through it and temporarily blocks the Sun's light.
An annular eclipse is a type of solar eclipse that occurs when the Moon is at its farthest point from the Earth, making it appear smaller in the sky. As a result, the Moon does not completely cover the Sun's disk, leaving a ring of sunlight visible around its edges. This creates a unique and stunning visual effect during the eclipse.
A total solar eclipse occurs on average about once every 18 months, but the duration and location of each eclipse varies. This is because the Moon's orbit around the Earth is slightly tilted, so it does not always perfectly align with the Sun and Earth during its monthly orbit. This means that not every solar eclipse is visible from the same location on Earth.
The corona is the outermost layer of the Sun's atmosphere, extending millions of kilometers into space. It is usually invisible to the naked eye because it is much dimmer than the Sun's surface. However, during a total solar eclipse, the Moon blocks out the bright surface of the Sun, allowing the corona to be seen. This is a rare opportunity for scientists to study this part of the Sun's atmosphere in detail.