Sunrise is defined as the moment the top of the sun’s disc first breaks the plane of the horizon in the morning, and sunset is when the top of the sun’s disc sinks below the horizon in the evening.

(Entry 1 of 3) 1 : the apparent descent of the sun below the horizon also : the accompanying atmospheric effects. 2 : the time when the upper limb of the sun disappears below the horizon as a result of the diurnal rotation of the earth. 3 : a period of decline especially : old age.

Rebirth. Sunrise and sunset are commonly used together – they’re the opposites, where the sunrise represents the birth and rebirth as it happens each day, while the sunset represents death and a conclusion to a chapter. Each day starts with a sunrise, which is symbolic of the act of rebirth.

Sunrise is defined as the instant in the morning under ideal meteorological conditions, with standard refraction of the Sun’s rays, when the upper edge of the sun’s disk is coincident with an ideal horizon.

Ever wondered where in the world is the first place to see the sun rise? Well, wonder no longer! North of Gisborne, New Zealand, around the coast to Opotiki and inland to Te Urewera National Park, The East Cape has the honour of witnessing the world’s first sunrise each and every day.

The sun is visible before actual sunrise and after actual sunset, because of atmospheric refraction. With altitude, the density and hence refractive index of air-layer decreases. As shown in Fig., the light rays starting from the sun travel from rarer to denser layers. They bend more and more towards the normal.

The Sun is visible to people on Earth about 2 minutes before the Sun rises above the horizon. This is due to the Refraction of light rays from Sun. The layers of air in the atmosphere have different densities. The difference is due to composition, pressure, and temperature.

Solution. The Sun appears about two minutes before the actual sunrise and this phenomenon is known as advance sunrise. The Sun remains visible about two minutes after the actual sunset and this phenomenon is known as delayed sunset. The advance sunrise and delayed sunset happen due to atmospheric refraction.

Ans. It is because of atmospheric refraction. When the Sun is slightly below the horizon, the light coming from it travels from less dense to more dense air and is refracted downwards. Thus, the Sun appears to be raised and can be seen 2 min before actual sunrise and 2 min after actual sunset.

What is a green flash? The green flash is an optical phenomenon that you can see shortly after sunset or before sunrise. It happens when the sun is almost entirely below the horizon, with the barest edge of the sun – the upper edge – still visible.

The rays of sun light below the horizon reach our eyes because of refraction of light due to apparent position of the sun. Hence we can see the sun for few minutes even it has actually set.

The light from the Sun travels through Earth’s atmosphere it undergoes scattering before it reaches us. Thus, there is more probability for shorter wavelength light to get more scattered than for the longer wavelength light. Hence, the Sun (and sunrise and sunset) appears reddish orange during sunset and sunrise.

During sunrise, the light rays coming from the Sun have to travel a greater distance in the earth’s atmosphere before reaching our eyes. In this journey, the shorter wavelengths of lights are scattered out and only longer wavelengths are able to reach our eyes. Therefore, the Sun appears reddish early in the morning.

Flames look yellow when they have have particles of unburnt carbon in them, and they look blue when there is no unburnt carbon present. The amount of unburnt carbon decreases as the flame gets hotter, so blue flames are indeed (usually) hotter than yellow flames. The Sun is not a flame as nothing is burning in it.

The term originates because for a blackbody all visible light will be absorbed rather than reflected, and therefore the surface will appear black. A star, like the Sun is a near perfect blackbody. A blackbody does not reflect any light, nor does it allow any light to pass through (transmit).

The daytime sky is blue because light from the nearby Sun hits molecules in the Earth’s atmosphere and scatters off in all directions. 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.

Blue stars

That’s even hotter. But the hottest known stars in the Universe are the blue hypergiant stars. These are stars with more than 100 times the mass of the Sun. One of the best known examples is Eta Carinae, located about 7,500 light-years from the Sun.

Tau Ceti

Stars live different lengths of time, depending on how big they are. A star like our sun lives for about 10 billion years, while a star which weighs 20 times as much lives only 10 million years, about a thousandth as long. Stars begin their lives as dense clouds of gas and dust.