The change between day and night is because of earth rotation . Abd the seasons’s change is caused by earth orbiting around the sun. When it is in spring and autumn, the day and night share the same time-period (12 hours/each season), while in summer, the day’ s time is longer than night’s time.

For us on the northern part of Earth, the shortest day comes at the solstice. After the winter solstice, the days get longer, and the nights shorter.

During the winter, the sun’s rays hit the Earth at a shallow angle. The sun’s rays are more spread out, which decreases the amount of energy that hits any given spot. The long nights and short days prevent the Earth from warming up.

The Earth spins around an imaginary line that runs between the South Pole and the North Pole. Because the equator is halfway between the North and South poles, the days there are always 12 hours of daytime and 12 hours of nighttime. There is very little difference between the seasons.

In Svalbard, Norway, which is the northern-most inhabited region of Europe, the sun shines continuously from April 10 to August 23. Visit the region and live for days, for there is no night.

At night, when that part of Earth is facing away from the Sun, space looks black because there is no nearby bright source of light, like the Sun, to be scattered. If you were on the Moon, which has no atmosphere, the sky would be black both night and day.

In space or on the Moon there is no atmosphere to scatter light. The light from the sun travels a straight line without scattering and all the colors stay together. Looking toward the sun we thus see a brilliant white light while looking away we would see only the darkness of empty space.

Albert Einstein’s special theory of relativity famously dictates that no known object can travel faster than the speed of light in vacuum, which is 299,792 km/s. Unlike objects within space–time, space–time itself can bend, expand or warp at any speed.

In reality it is no darker than any other part of the Moon’s surface as sunlight does in fact fall equally on all sides of the Moon. It is only ‘dark’ to us, as that hemisphere can never be viewed from Earth due to a phenomenon known as ‘Tidal Locking’.

Our sun is one object in the sky that everyone can see, but no one can look at. Far and away the brightest object in the sky, the sun is easy to find, but it’s so bright that one can’t look directly at it without vision damage. SOHO stands for Solar and Heliospheric Observatory.

This occurs when UV light literally burns a hole in the retinal tissues. It destroys the rods and cones of the retina and can create a small blind spot in the central vision, known as a scotoma. The retina does not have any pain-receptors, so you won’t feel the damage being done.

Too much visible light can penetrate your eye and damage the retinal tissue, which causes a condition called solar retinitis. This means parts of your retina can no longer process light normally, so you can end up with entire chunks of your vision blurred out. So do your eyes a favor and avoid looking at it.

First, staring directly at the sun can damage a part of the retina — which is responsible for the center of your vision — causing a condition called solar retinopathy. Solar retinopathy is like a sunburn on the retina, a layer of tissue at the back of your eye, Habash tells BuzzFeed Health.

Don’t ever look directly at the Sun through a telescope or in any other way, unless you have the proper filters. The easiest and safest is to project the Sun by building your own pinhole camera. Or, if you have your own telescope, you will need to obtain a solar filter.

The danger is obvious: its disk is so bright that prolonged, direct exposure can cause permanent damage to the retina, leading to loss of vision or blindness. To observe the Sun safely, you need to filter out more than 99% of the Sun’s light before it reaches your eyes.

Smoke obscuring the sun makes it easier to stare at, but eye experts warn people not to. But that’s not a good idea, ophthalmologists and other eye experts say. While smoke particles in the air can diminish the brightness of the sun, ultraviolet light is not affected.

It’s important to note that you should never look at the sun through an unfiltered camera, telescope or binoculars, regardless of whether you’re wearing eclipse glasses. That’s because these devices will focus the sun’s rays even more than your eyes do, Van Gelder said, and this can cause serious eye injury.

The corona is usually hidden by the bright light of the Sun’s surface. That makes it difficult to see without using special instruments. However, the corona can be seen during a total solar eclipse. During a total solar eclipse, the moon passes between Earth and the Sun.

The short answer is if you squeeze your eyes shut very tight and then face the Sun, that should be enough to protect your eyes from damage. You won’t go blind. You should never look directly at the Sun, with or without sunglasses, even during a solar eclipse, because that can cause a lot of damage to the eyes.

Warning: NEVER look directly at the sun through binoculars, a telescope or with your unaided eye. Serious eye damage and even blindness can result.

The research on sun gazing and its benefits is limited. However, some people who practice it say it boosts their energy levels, reduces stress, and helps them feel more grounded, centered, and positive….Benefits for mental health

• increased dopamine and serotonin.
• an improved mood.
• a reduction in depressive symptoms.

Exposing your eyes to the sun without proper eye protection during a solar eclipse can cause “eclipse blindness” or retinal burns, also known as solar retinopathy. It can take a few hours to a few days after viewing the solar eclipse to realize the damage that has occurred.

Photokeratitis is a painful, temporary eye condition caused by exposure to ultraviolet (UV) rays, most commonly from the sun.