I was looking at the statistics of power consumption of the world. From all forms of energy sources we are currently using around 15TW of power. Whereas, solar energy reaching our Earth is 6000 times more than our energy consumption.
Sun radiates energy in all directions and only a very tiny portion of that reaches our Earth. Thermonuclear fusion of hydrogen into helium is the source of solar energy. 620 Million Metric Tonnes of hydrogen is consumed every second. A small portion of that, that is 4.26 Million Metric Tonnes is fully transformed into energy to produce 3.846 x 10^26 Watts. Sun consumes an Earth Mass equivalent of hydrogen in 305000 years producing an Earth Mass equivalent of energy in every 45 Million years. So the mass of the Sun is getting reduced by one Earth Mass in this period of time. In the 4.5 Billion year history of the Solar system, Sun produced around 100 Earth Mass equivalent of energy. That seems to be very huge, but that is only 0.03% of the Solar mass.
But remember that our Sun is an ordinary star in our galaxy, the Milky Way. There are many billion stars in the Milky Way and there are many billion galaxies in the Universe.
Many of the stars we see are actually much brighter than the Sun, but do not appear bright because of the larger distance. The term ‘Luminosity’ is used to measure the brightness of a star without considering its distance. Luminosity is the measure of the energy production of the star relative to that of our Sun.
The most luminous first order magnitude star is Deneb belonging to Cygnus constellation. It is around 200000 as bright as the Sun.
The Super Powers of Orion
From antiquity, Orion is regarded as one of the most prominent constellations. It is also an interesting fact that Orion has some of the important first order magnitude stars.
Betelgeuse: Known as Alpha Orionis. It is a red supergiant with a diameter more than 1000 times that of Sun. Placed in the centre of the Solar system that would reach upto Jupiter. It produces around 140000 time more energy compared to the Sun. That is an Earth Mass equivalent of energy in 320 years. Had Betelgeuse been our nearest visible star instead of Alpha Centauri, it would have been nearly as bright as the full Moon.
Rigel: On the other side, it is a blue supergiant also known as Beta Orionis. It has a luminosity of more than 100000 that of the Sun. If a planet has to get similar amount of light as our Earth, it has to be at a distance of more than 300AU, that means at a distance 8 times that of Pluto.
Alnilam, Alnitak, Mintaka: These three stars form the belt of Orion. All of them are blue supergiants with a luminosity more than 100000 as the Sun.
While seeing those “Twinkle Twinkle Little Stars”, do remember that they produce unimaginable amount of energy.