Give reasons the following:The sun can be seen about 2 minutes before actual sunrise. (2024)

FAQs

Give reasons the following:The sun can be seen about 2 minutes before actual sunrise.? ›

It is because of atmospheric refraction

The sun is visible to us 2 minutes before the actual sunrise because of atmospheric refraction. When the sun is below the horizon the light travelling from rarer to denser medium bends and reaches our eyes creating an impression that it is above the horizon.

Advanced sunrise and delayed sunset are phenomena caused due to atmospheric refraction. In this the Sun appears to rise early by 2 minutes and set late by 2 minutes. The diagram below shows this phenomenon. When the rays from the Sun hit the atmosphere they get refracted.

Due to the continuous refraction of light rays at each layer, it follows a curved path and reaches the eye of the observer. As a result, we can see the sun for 2 minutes before it rises above the horizon in the morning.

The distance between earth and sun is 1485 lakh kilometres. Due to this, sunlight takes 8 ¹/ ₄ minutes of time to reach earth. Thus, we see the sun rising 8 ¹/ ₄ minutes after it has actually risen.

Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizon.

Civil Twilight: Begins approximately 30 to 40 minutes before sunrise. This is when the sky starts to lighten up, and the highest clouds catch the first pink, orange, and red hues. It's also when features on the ground start to become visible.

What is the reason for the early sunrise? Near the horizon, the light from the Sun bends towards normal. As a result, the Sun appears to be above the horizon. This is why the sun rises so early.

Since Earth's orbit is not completely round, the Earth sometimes finds itself closer to the Sun. In fact, the Earth is about 3 million miles closer to the Sun in January than in July. These changes impact what time the Sun rises and sets.

Today's sunrise snapshot is from Fairbanks, Alaska. Sunrise and sunset times constantly fluctuate during the year due in part to Earth's tilt and the changing of the clocks for daylight saving time. Sunrise officially begins when our giant star starts to appear above the horizon, marking the end of twilight.

How is sunrise determined? ›

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.

As the Earth rotates toward the east, it looks like the sun is moving west. As the Earth rotates, different locations on Earth pass through the sun's light. The animation shows how that looks hour by hour (for 4 hours). As your town turns toward the sun and begins to enter its light, the sun seems to rise in the east.

Because of its motion on the ecliptic, the Sun rises about 4 minutes later each day with respect to the stars. Earth must make just a bit more than one complete rotation (with respect to the stars) to bring the Sun up again.

Because the Sun is eight light minutes away from the Earth, that means that it takes light eight minutes to get from the Sun to the Earth, where the sunlight is scattered by the gases in the atmosphere, and because Rayleigh scattering is inversely proportional to the fourth power of the wavelength, this means that the ...

From horizon to horizon, the Sun's track is longer in summer and shorter in winter; so that in summer, sunrises are much earlier and sunsets are much later than in winter. See, for example, the graphic below, or this photograph of the Sun's paths through the sky at different times of the year.

We see the sunrise and sunset because of Earth's rotation about its own axis. Earth is rotating about its own axis from West to East. So, when seen from the Earth, the Sun appears to rise in the East and set in the West.

Because Earth moves around the Sun (roughly 1° per day), after one complete rotation of Earth relative to the stars, we do not see the Sun in the same position. Because our ordinary clocks are set to solar time, stars rise 4 minutes earlier each day.

When the sun sets, we lose the heat from the sun, but the Earth continues to exert its heat into the atmosphere. Moments before sunrise is when we hit the lowest amount of solar radiation because the sun has not transferred an additional heat in our area in hours.

The stage of sunrise known as false sunrise actually occurs before the Sun truly reaches the horizon because Earth's atmosphere refracts the Sun's image. At the horizon, the average amount of refraction is 34 arcminutes, though this amount varies based on atmospheric conditions.

Since blue colour has a shorter wavelength and red colour has a longer wavelength, the red colour is able to reach our eyes after the atmospheric scattering of light. Therefore, the Sun appears reddish early in the morning.