January 4, 2016

Solar Fact of the Week: It takes less than 10 minutes for light to travel from Sun to Earth. Here’s why…

close up image of the sun

The sun is a massive ball of fire. The Sun is the axis of the Solar System and is the main resource of energy for life on Earth. It is a perfect sphere-shaped ball of plasma. The Earth is the third planet from the Sun, and the largest of the grown-up planets. Our Sun is a normal main series G2 star, one of more than 100 billion stars in our galaxy. It has a diameter of 1,390,000 Km and a mass of 1.988 × 10^30 kg .its temperature is 5800 K (surface) 15,600,000 K (core).

How Far is Earth from the Sun?

Sometimes earth moves closer to the sun and sometimes farther away from the sun. Earth’s closest loom to the sun comes in early January and is about 91 million miles. Earth farthest from the sun comes in early July and is about 94.5 million miles. The distance from Earth to the sun is called an astronomical unit. The AU has been defined as 149,597,870,700 meters. The average distance from the Earth to the Sun is 1 astronomical unit, or 1 AU.

How long does sunlight take to reach the sun?

This sounds like an odd question, but think about it. Sunlight travels at the speed of light. Photons emitted from the surface of the Sun need to travel 1AU to reach us.The short answer is that it takes sunlight an average of 8 minutes and 20 seconds to reach to the Earth. But the story of light gets even more motivating, when you think about the drive light needs to make inside the Sun.You know that photons are created by fusion reactions inside the Sun. They start off as gamma radiation and then are emitted and absorbed countless times in the Sun before they finally reach the surface. What you don’t know, is that the photons striking your eye were created hundreds of years ago and it took that long for them to be emitted by the sun. Actually photon takes 20,000 years to travel from the core of the sun to its surface.

Once they escaped the surface, it takes only 8 minutes for those photons to cross the vast distance from the Sun to the Earth. When you look outward into space, you’re actually looking backwards in time. The light reflected from the surface of the Moon takes some seconds to reach the Earth. The Sun is more than 8 light minutes away. The light from the nearest star (Alpha Centauri) takes more than 4 years to reach us.

Solar light as the greatest energy source….

The energy of sun is beyond thoughts. The surface of the earth receives 120000000000 megawatts of solar radiation, 20,000 times more power than which needed to supply the whole world. Solar energy is a renewable power source. This means that we cannot come to an end of solar energy. We will enjoy the solar energy till the sun is alive. Another 6.5 billion years according to NASA.