…Continued from last Sunday

What is the size of the sun and where does it get its energy? 

Last time, we saw the Sun’s diameter is 864,938 miles (1,391,980 km) and almost 10 times larger than the planet Jupiter and about 109 times as big as the Earth. Its volume is 1,299,400 times bigger than the volume of the Earth, and about 1,300,000 Earths could fit inside the Sun..

The chromosphere layer is above the photosphere layer. Solar energy passes through this region on its way out from the centre of the Sun. Faculae and flares arise in the chromosphere.

Faculae are bright luminous hydrogen clouds, which form above regions where sunspots (Sunspots are temporary phenomena on the surface of the Sun that appear visibly as dark spots compared to surrounding regions) are about to form.

Flares are bright filaments of hot gas emerging from sunspot regions. Sunspots are dark depressions on the photosphere with a typical temperature of 4,000°C (7,000°F).

The corona is the outer part of the Sun’s atmosphere. It is in this region, that prominences appear. Prominences are immense clouds of glowing gas that erupt from the upper chromosphere.

The outer region of the corona stretches far into space, and consists of particles travelling slowly away from the Sun. The corona can only be seen during total solar eclipses.

According to scientists, the Sun appears to have been active for 4.6 billion years and has enough fuel to go on for another five billion years or so.

At the end of its life, the Sun will start to fuse helium into heavier elements and begin to swell up, ultimately growing so large that it will swallow the Earth.

After a billion years as a red giant (A red giant is a luminous giant star of low or intermediate mass roughly 0.5-10 solar masses that is in a late phase of stellar evolution), it will suddenly collapse into a white dwarf, the final end product of a star like ours. It may take a trillion years to cool off completely.

The Sun rotates on its axis once in about 27 earth days. The Sun’s rotation axis is tilted by about 7.25 degrees from the axis of the Earth’s orbit, so we see more of the Sun’s North Pole in September of each year, and more of its south pole in March.

Since the Sun is a ball of gas, it does not have to rotate rigidly like the solid planets and moons do. In fact, the Sun’s equatorial regions rotate faster (taking only about 24 earth days) than the Polar Regions (which rotate once in more than 30 days).

The source of this "differential rotation” is an area of current research in solar astronomy.

Is there any possible life after our sun dies according to scientists?

The Solar System has evolved considerably since its initial formation. Many moons have formed from circling discs of gas and dust around their parent planets, while other moons are believed to have formed independently and later been captured by their planets e.g. Jupiter has 60 moons and Saturn has 31 moons.

Still others, as the Earth’s one Moon, may be the result of giant collisions. Collisions between bodies have occurred continually up to the present day, and have been central to the evolution of the solar system.

The positions of the planets often shifted, and planets have switched places. This planetary migration now is believed to have been responsible for much of the Solar System’s early evolution.

In roughly 5 billion years, the Sun will cool and expand outward to many times its current diameter (becoming a red giant), before casting off its outer layers as a planetary nebula, and leaving behind a stellar corpse known as a white dwarf.

In the far distant future, the gravity of passing stars gradually will whittle away at the Sun’s retinue of planets. Some planets will be destroyed, others ejected into interstellar space (is the physical space within a galaxy not occupied by stars or their planetary systems).

Ultimately, over the course of trillions of years, it is likely that the Sun will be left alone with no bodies in orbit around it.

A white dwarf star is what happens to stars after they die. In the far future according to scientists, our own Sun will eventually become a white dwarf star.

Astronomers believe that white dwarf stars, are the final evolutionary stage of stars with roughly the mass of the Sun. For the majority of its life, a solar mass star is in the main sequence phase, converting hydrogen into helium in its core.

Once the star runs out of hydrogen fuel, fusion in the core shuts down. A thin shell of hydrogen around the core then ignites, puffing the star out to become a red giant.

But once this final amount of hydrogen fuel runs out, and it doesn’t have enough mass to fuse helium into carbon in its core, the star collapses down.

It will shed its outer layers forming a planetary nebula, and all that remains is the hot, dead core of the star. At this point, the white dwarf star lacks the core temperatures and pressures to fuse atoms together.

The light and heat coming off from it are purely the leftover heat from when the star was hot and bright. Over billions of years, it will slowly cool down until it becomes the background temperature of the Universe. At this point it will become a black dwarf star.

This takes a long time, though. Even the oldest white dwarfs still radiate at temperatures of a few thousand kelvins, so no black dwarfs are believed to have formed yet.

Ends