How much lux does the Sun emit? - Physics Stack Exchange
When you look 'at the world' (i.e. to the horizon) on a clear day, unlesss the sun is at a very low angle, the surface of your eye is not illuminated directly by the sun, only reflected sunlight from the atmosphere, ground and objects. The 32,000-100,000 lux figure is referring to a horizontal surface illuminated directly by the sun.
everyday life - Why do sunbeams diverge even though the sun is …
2014年12月26日 · The same applies to the beams of light above them. The Sun is very far away and the beams are pretty much parallel, but they're pointing towards you, and perspective makes them appear to converge towards the vanishing point - which in this case is the Sun's location in the sky. The technical term for these beams is "crepuscular rays."
How is distance between sun and earth calculated?
2011年2月15日 · Another way of calculating the earth - sun distance is to look at the centrifugal and the gravitational force. This solution assumes that one already knows the mass of the sun, but thats a different problem ;-).
sun - Why is sunlight spectrum continuous? - Physics Stack …
The continuous spectrum of the visible photosphere of the Sun is attributable to the radiative equilibrium of the $\mathrm{H}^{-}$ ion. This has been recognised for at least 80 years ( Wildt 1939 ). This ion forms by the attachment of a free electron (with a continuous spectrum of energies) to a hydrogen atom, emitting a continuous spectrum of ...
How can sunlight be white , but pictures of the sun be orange?
The Sun is white, but the reason why it is white is because your brain adjusts the white balance to make the totality of all the ambient light illuminating the objects you see, white. Now, the Sun is too bright to look directly at safely, but around dusk or dawn you can sometimes see by accident a glimpse of it, and it then looks red.
How does the Earth's orbit change as the Sun decreases in mass?
2020年3月10日 · Now the Sun loses a small amount of mass. The Earth is still traveling at the same velocity, and requires the same centripetal force to maintain the same circular orbit. Unfortunately, the reduced mass of the Sun no longer supplies the required centripetal force. So the Earth is now in a slightly elliptical orbit, passing perihelion.
Why does the Sun always rise in the East? - Physics Stack Exchange
2014年11月26日 · At noon, the Sun is above the observer, and east points backward, against the orbital motion. At sunset, east points away of the Sun, because the planet made a half-revolution with respect to Sun and the observer is now near the centre of the trailing Earth hemisphere (lower side of the blue disk).
How hot can metal get in sunlight? - Physics Stack Exchange
2015年5月31日 · If the building is located in Hammerfest, Norway the metal might get warm to the touch. If it's on the sun-facing side in Las Vegas you may find it gets hot enough to cause burns. A definitive answer is not possible. If people can touch it easily the temperature is a concern. If it's out of reach, don't worry about it. The iron isn't going to melt.
What is the simplest way to prove that Earth orbits the Sun?
2015年4月17日 · If we assume the Sun orbits the Earth, the math says that the Sun should be much less massive than the Earth. If we assume the Earth orbits the Sun, the opposite is true. Either way we can get an estimate of the mass of the Sun. We know from other tests that the Sun is more massive than the Earth, so therefore the Earth orbits the Sun.
orbital motion - Earth-Sun distance on a given day of the year ...
2015年4月23日 · But if you want to calculate more accurately the distance between the Earth and the Sun at any given epoch, you need to look up for Kepler's Equation. This can be obtained using Kepler's laws of planetary motion, or just solving 2-body problem : that it would still be an approximation, but much more accurate than the one given in your question.