The moon does not produce its own light. We can only see the moon when light coming from the sun is reflected off of its surface. This means that whenever the moon reflects the sun's rays we can see it–even in the day time.

The visibility of the moon during the daytime also depends on its angle and its distance from Earth. When the moon and sun are on the same side of Earth, the moon is visible during the day; when the moon and sun are on opposite sides of the Earth, the moon is not visible during the day, as the Earth is blocking sunlight from reaching the moon's surface.

The reason we can see the moon and not stars during the day is because the sunlight reflected off of the the moon makes it 100,000 times brighter than the brightest star in the sky.

Liquid water cannot persist at the moon's surface, and water vapor is decomposed by sunlight, with hydrogen quickly lost to outer space. However, scientists have conjectured since the 1960s that water ice could survive in cold, permanently shadowed craters at the Moon's poles.

We can see the moon during the day for the same reason we see the moon at night. The surface of the moon is reflecting the sun's light into our eyes. ... "When we see the moon during the day it's because the moon is in the right spot in the sky and it's reflecting enough light to be as bright, or brighter, than the sky.

The moon shines because its surface reflects light from the sun. ... At any given point in the moon's trajectory around the Earth, only half of its surface is facing the sun, and therefore, only half of the moon is lit up. The other half of the surface faces away from the sun and is in shadow.

The Earth has a surface area of 197 million square miles. Multiply that by four billion, and you have the Earth's surface area in square inches. With atmospheric pressure being an average 14.7 lbs (6.6kg) per square inch, the sky weighs roughly 5.2 million billion metric tons. Another way of looking at it, according to the United Kingdom's Science and Technology Facilities Council, is in its equivalent to Indian elephants. By that measure, the sky weighs equal 570,000,000,000,000 adult Indian elephants.

The highest clouds are no higher than 12 kilometers (7.5 miles) above ground, so that altitude could be considered the “height of the sky”. Others might argue it is the boundary between the atmosphere and space, which scientists give as 100 kilometers (62 miles) above ground.

The Earth weighs 5.972 x 10^24 kg, or around 6,000,000,000,000,000,000,000,000 kg. However, the Earth technically weighs nothing, because weight depends on the gravitational pull acting on an object and the Earth is floating in space. Still, mathematicians got the number above by looking at the strength of Earth's gravitational pull on nearby objects.

About 1.3 million Earths could fit inside the sun. The mass of the sun is 1.989 x 10³⁰ kilograms, about 333,000 times the mass of the Earth. The sun contains 99.8 percent of the mass of the entire solar system, leading astronomers Imke de Pater and Jack J.

Airplane pilots usually only use this function for stopping once they land. When an airplane backs out of a gate at an airport, it relies on the use of tow cars to push it onto the runway. If the pilot were to engage the thrust reverser while parked in the gate, the amount of force coming from the thrusters would damage the airport as well as the people and vehicles on the ground.

This is a rule outlined by the laws of physics. Everything is always falling, but an aircraft can appear to stand still in the air by stabilizing its altitude. A helicopter, for example, appears to stand still in the air as its propeller pulls the aircraft up at the same rate gravity pulls it down. An airplane, too, can appear to stand still if there is a strong headwind coming towards it that keeps it in place.

Planes stay in the air because of the shape of their wings. Air moving over the wing gets forced downwards, which pushes the wing up. This push is stronger than gravity, and so makes the plane fly.

Yes. Dry water is an unusual form of powdered liquid. It is a water-air emulsion in which liquid droplets the size of a grain of sand are surrounded by a silica coating. Dry water consists of 95 percent liquid, but the silica coating prevents the droplets from combining and becoming a bulk liquid. The result is a white powder that looks similar to table salt.

"Wet" is ultimately just a word that applies to water. What we feel as wetness is actually coldness as the water evaporates. Below is an experiment from the Institute of Physics to test the feeling of "wetness" between two different liquids

This is a very technical subject that the video below deals with very nicely. Planes take advantage of Newton's third law of physics, which states that for every action, there is an equal and opposite reaction. As air moving over the wing gets forced down, there is an equal and opposing force generated. This is a combination of the bottom of the wing getting pushed up, and the top of the wing getting pulled up.

There are only seven colours in a rainbow because only seven colours are included on the visible spectrum. While there are many more colours that are refracted when sunlight passes through a raindrop or glass prism, only seven can by seen by the human eye.

White colour is actually a mix of several different colours. Each constituent colour of a rainbow is caused by a specific wavelength of light. When light hits a medium that forces it to slow down, the light ray bends, but not equally. Each wavelength bends by a certain amount, which causes the different coloured rays of light to exit the raindrop in slightly different directions. This results in the colours fanning out. When sunlight goes through droplets of water, the beam of light is split into the different colours that make up light.

A rainbow is curved because it reflects the round shape of the sun. Because you are on Earth, part of the sun is blocked, which why rainbows appear as a half or a quarter circle. If you were in an airplane and saw a rainbow below you, it would appear as a full circle.

To be electrocuted you must be part of a complete circuit. This means you must touch both a positive wire, and a negative or neutral wire (or "ground"). If a bird was touching the ground while touching the wire, the ground would act as a neutral wire and the current would flow through the bird, electrocuting it. If the bird sat on a wire and touched the metal of the pylon or another wire, it would also complete a circuit and get electrocuted.

Electric shock occurs upon contact of a (human) body part with any source of electricity that causes a sufficient current through the skin, muscles, or hair. ... The minimum current a human can feel depends on the current type (AC or DC) and frequency.

The shock can cause a burn where the current enters and leaves your body. The electricity may have injured blood vessels, nerves, and muscles. The electricity also could have affected your heart and lungs. You might not see all the damage the shock caused for up to 10 days after the shock.

Aliens definitely exist, Britain's first astronaut has said -- and it's possible they're living among us on Earth but have gone undetected so far.

Helen Sharman, who visited the Soviet Mir space station in 1991, told the Observer newspaper on Sunday that "aliens exist, there's no two ways about it."

"There are so many billions of stars out there in the universe that there must be all sorts of different forms of life," she went on. "Will they be like you and me, made up of carbon and nitrogen? Maybe not."

We don't have any proof to state that aliens do exist, but we also don't have any proof to state that they do not. While we know there are planets orbiting stars at the right distance for liquid water to exist, we have no idea if there is any form of life beyond our planet.

The birds that do not migrate in the winter utilize certain survival techniques to make it through the cold months. First, they grow extra feathers in the months leading up to winter so they can keep warm. Birds can also fluff up their feathers to make air pockets that keep them even warmer.

In areas with colder climates, some common bird foods (such as insects, nectar, small animals, small reptiles) disappear for the season. The birds that rely on these foods fly south for the winter months, where they are more likely to find their favorite foods. Other birds, such as those that feed on subterranean insects or bugs that burrow within the bark of trees, stick around for the winter months, as their supply of food is constant.

In the months before a spell of cold weather, birds also increase their fat intake. With more fat, they are able to generate more heat when they need it. Some birds even feather flock together, which is when they pack together in a tight huddle and share body heat.