I can't answer your first question but i can explain the last one.
On Earth, when sunlight passes through our atmosphere, it scatters off molecules and particles, making the sky blue during the day.
Instead, Space is almost empty, it means that there isn't so much matter that could reflect or scatter sunlight.
Sun blocking' technologies also known as 'solar radiation modification' could theoretically cool down the earth by reflecting sunlight back into space. One idea involves pumping sun-blocking particles into the upper atmosphere. Cryosphere (snow and ice): Cools Earth by reflecting incoming sunlight, limiting how much heat is absorbed by the surface. Atmosphere (air): Insulates Earth by trapping heat and transporting heat and water vapor.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. This is the case with space. The sun's radiation may travel through it, but there are no molecules or atoms to absorb that heat. Even when a rock is heated above 100°C by the sun's radiation, the space around it will not absorb any temperature because of the same reason. To an astronaut, the sky looks dark and black instead of blue because there is no atmosphere containing air in the outer space to scatter sunlight. So, there is no scattered light to reach our eyes in outer space, therefore the sky looks dark and black there. Geochemical and sedimentary evidence indicates that Earth experienced as many as four extreme cooling events between 750 million and 580 million years ago. Geologists have proposed that Earth's oceans and land surfaces were covered by ice from the poles to the Equator during these events. Because space is a near-perfect vacuum meaning it has exceedingly few particles there's virtually nothing in the space between stars and planets to scatter light to our eyes. And with no light reaching the eyes, they see black.Once the light hits and bounces off of an object, it is the atmosphere that allows the 'scattering' and the ability to see colors in the spectrum that our eyes see. The surrounded 'space' appears black because there isn't a strong enough atmosphere to cause the 'scattering'.
On the same as above principle, cooling may occur naturally. All we need is a good volcanic eruption (like Crakatoa ..)
Because the colour our eyes see is because of light reflected by an object. In space there is no object so it appears black. But in earth's atmosphere, dust, air and moisture reflect and diffract the light. This phenomeon is as rayleigh scattering. So what we see is a pale blue sky. As far as wavelengths go, Earth's sky really is a bluish violet. But because of our eyes we see it as pale blue.To an astronaut, the sky looks dark and black instead of blue because there is no atmosphere containing air in the outer space to scatter sunlight. So, there is no scattered light to reach our eyes in outer space, therefore the sky looks dark and black there. Sun blocking' technologies also known as 'solar radiation modification' could theoretically cool down the earth by reflecting sunlight back into space. One idea involves pumping sun-blocking particles into the upper atmosphere. While that sounds pretty alarming, some estimates for the cooling of Earth's core see it taking tens of billions of years, or as much as 91 billion years. The planet has generally been cooling for the last 50 million years or so, as plate tectonic collisions thrust up chemically reactive rock like basalt and volcanic ash in the warm, wet tropics, increasing the rate of reactions that draw carbon dioxide from the sky. Past studies have shown that the cooling trend is driven by greenhouse gases, as well as shifts in the Earth's magnetic field and the roughly 11-year cycle in the sun's solar activity. Since 1880, average global temperatures have increased by about 1 degrees Celsius (1.7° degrees Fahrenheit). Global temperature is projected to warm by about 1.5 degrees Celsius (2.7° degrees Fahrenheit) by 2050 and 2-4 degrees Celsius (3.6-7.2 degrees Fahrenheit) by 2100. A high carbon pathway, temperatures in India could increase by as much as 1.8°C by 2050. On a low carbon pathway this drops to 1.2°C. , India's population density is likely to decrease to 335 persons per km sq by 2100 and it is projected that the fall may be higher than what is projected for the entire world. The temperature at the surface of the Sun is about 10,000 Fahrenheit (5,600 Celsius). The temperature rises from the surface of the Sun inward towards the very hot center of the Sun where it reaches about 27,000,000 Fahrenheit (15,000,000 Celsius). Things really warm up when radiation from a star reaches a spot in space with a lot of particles. This gives the radiation from stars like the sun something to actually act upon. That's why Earth is a lot warmer than the region between our planet and its star. 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. Because space is a near-perfect vacuum meaning it has exceedingly few particles there's virtually nothing in the space between stars and planets to scatter light to our eyes. And with no light reaching the eyes, they see black. Most of the space is empty, as the gas molecules in space are so few and far from each other that they do not collide regularly with each other, so even when the sun heats them with infrared waves, this heat transfer through conduction is not possible.If you were out in space, or on the moon, the sun would look white. In space, there is no atmosphere to scatter the sun's light. On Earth, some of the shorter wavelength light (the blues and violets) are removed from the direct rays of the sun by scattering. The remaining colors together appear yellow.
- Badges
- Science topic