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| © Eugene Brennan |
As
you probably know, the Sun is a giant nuclear reactor, the cosmological
equivalent of a hydrogen bomb. It’s our nearest star and it would take
600 years to cycle there at a leisurely pace of 12 miles per hour, 24/7.
That’s if there was actually a road we could travel on! Even at a
distance of 93 million miles, we feel its heat, and it lights our world
and has a huge influence on planet Earth. Without the Sun, the Earth
would eventually become a cold, frozen place as the temperature of the
planet continued to fall to hundreds of degrees below zero. The Sun
drives the climate and it creates the energy necessary for crops to
grow. Without sunshine, the chemical process known as photosynthesis
can’t take place, since plants need light energy to turn CO₂ and water
into sugar and starch in their roots, stems and leaves. Without plants,
animals can’t survive either, because herbivores eat plants and
carnivores in turn eat the herbivores that eat the plants. The Sun was
also responsible for providing the energy that is now locked into fossil
fuels. Refined oil products and gas originated from dead marine
organisms which over millions of years metamorphosed into crude oil.
Those organisms, such as plankton, algae and other sea creatures relied
on the energy of the Sun for life. Similarly coal originated from trees
in ancient forests, pressed into a rock-like material by huge pressures
from above. Our renewable energy sources today all derive their energy
from the Sun. Solar panels convert sunshine directly into electricity.
Wind, wave, tidal and hydro power wouldn’t be possible without the
motion of air and sea caused by solar energy heating the ground surface
and oceans and generating air currents.
Like
most stars, the Sun formed when clouds of dust left over from the
formation of the Universe coalesced under the influence of gravity into
clumps. The process took millions of years and planets in our Solar
System formed similarly. The swirling clumps slowly became more defined
and spherical. Small clumps became planets, but the larger clump at the
centre of the Solar System continued to become tighter and more
compressed. Newton’s law of universal gravitation states that:
“Every particle attracts every other particle in the universe with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between their centres.”
The
consequences are that the force of gravity is stronger if either or
both particles have greater masses and are closer together.
In
the case of the Sun, the sheer volume and weight (or more correctly
mass in this context) of the clump at the centre of the Solar System
meant that there was colossal gravity, and that gravity continued to
pull everything together towards a common centre. As everything
continued to get closer together, the “distance apart” in Newton’s law
became smaller. The result was a runaway situation with distance getting
smaller and gravity increasing because of the increasingly smaller
distances between particles. Eventually atoms were squeezed into one
another, ultimately sparking off a fusion reaction (something we've
being artificially doing for decades in experiments on Earth in the
quest for fusion power). The process didn’t continue however and
eventually there was equilibrium between the heat of the thermonuclear
reaction causing expansion and gravity pulling inwards.
Facts about the Sun
• It’s 93 million miles or 149 million km from Earth.
• The Sun is approximately 4.6 billion years old.
• It has a diameter of approximately 864,600 miles or 1,391,400 km.
• Eventually the Sun will become a red giant star, swallowing up the inner planets including Earth in 7.59 billion years time.
• Ultimately the Sun will become a white dwarf with 54% of its original mass.
Weight
is something that changes depending where you are in the Universe. An
astronaut weighs less on the Moon, but their mass is the same. Both mass
and weight are measured in kg.
Many thanks to ChatGPT for making up the title!
References:
- How does the Sun work? | High Altitude Observatory. (n.d.). https://www2.hao.ucar.edu/.../about-the.../how-does-sun-work
- K.-P. Schröder, Robert Connon Smith, Distant future of the Sun and Earth revisited, Monthly Notices of the Royal Astronomical Society, Volume 386, Issue 1, 1 May 2008, Pages 155–163, https://doi.org/10.1111/j.1365-2966.2008.13022.x