Our magnificent Sun. Our natural provider of light, warmth, and life. Even at a distance of ~ 93 million miles from Earth our star burns with such intensity that we are obliged to wear protective eyewear when attempting to gaze at it. 93 million miles puts the Sun 372 times more distant than our Moon. As discussed in a previous post Speed of Light and Vastness light travelling at a speed of 186,000 miles per second takes 8.3 minutes to travel from the Sun to the Earth. And yet, even at such an astounding distance, our Sun exerts amazing control over our small blue planet. What is the life expectancy of our Sun? As with all natural things, death does await our star. The death of our Sun will mean the death of Earth.
The Birth, Structure and Life Expectancy of our Sun
Our Sun is somewhere between 4.4 and 4.8 billion years old. In the vastness of time our star is relatively young. It is composed of typical star material, namely hydrogen and helium. Evidence indicates that the Sun was formed from a solar nebula—a large cloud of gas and dust. Some of that nebula was consumed in the formation of planets and moons within our solar system, but the bulk of that material wound up as part of our Sun.
The interior of the Sun is so dense that photons formed within its interior can take hundreds of thousands of year to reach its surface. Think of that for a moment. The photons of light that we see today were formed ions ago—long before the appearance of our species on this planet.
In addition to its live-giving properties our Sun also periodically creates havoc here on Earth. Wild variations in the Sun’s magnetic field results in Sun spots and violent solar flares. Solar flares release millions of tons of high-energy particles into space. These particles are carried by the solar wind and, depending on direction and magnitude, can create significant disruption within our communication channels. Especially vulnerable are the many communication satellites orbiting the Earth. Astronauts that happen to be in space during a massive solar flare are also at risk. Monitoring the condition of the Sun is a critical factor in trying to minimize the potential health risks to astronauts.
www.space.com has some cool videos about the Sun.
The Death of our Sun
At an age of ~ 4.6 billion years our Sun has reached middle age. It has been relatively stable for the last few billion years and most helioseismologists predict that that stability will continue for another ~ 5 billion years. At that remote point in the future our Sun will begin its death spiral. Our Sun does not have enough mass to produce a “Super Nova”. It is predicted that as it begins to die—as its supply of hydrogen becomes depleted—the Sun’s outer layers will start to expand. Eventually those outer layers will expand to the point that the planets closest to the Sun will be engulfed. The Earth is one of those planets. Any living thing that had not managed to escape our planet will be roasted and consumed. Our Earth will be no more.
At the point that those outer solar layers have finally been cast off the core of the Sun will have shrunken to a puny mass only a few thousand miles in diameter. Our Sun will have turned into a white dwarf star. An ignominious end to ~ 10 billion years of solar system dominance. Maybe another Sun will form in its place. That will not be for us to find out.
A Long Time to Prepare
So……at least we have a little time to prepare for the death of our Sun. We, as a species, have at least 4 billion years or so to plot our escape from our home planet. But, on the other hand, what are the odds that—through our own stupidity—we will not have destroyed our blue haven long before our Sun does the deed for us? Personally, I would bet against us……
We can always hope that the alien builders of the Great Pyramids will return to rescue us!
Other Cool Facts About our Sun
- The diameter of the Sun is 870,000 miles or approximately 120 times the diameter of Earth.
- The Sun is so massive that it constitutes—by itself—~ 99% of the total mass within our entire solar system. That means that all the planets, moons, rocks, comets, etc. combine to make up a paltry 1%.
- The surface of the sun burns at ~ 10,000 degrees Fahrenheit while the core cooks at an unimaginable 25,000,000 degrees.
- Our star is just one of many……very many! It is estimated that there are at least one hundred billion—that is 100,000,000,000—stars in our Milky Way galaxy. Combine that with the fact that there are billions of individual galaxies and, well, you end up with a number of stars that is basically unfathomable.
- The Sun is a near perfect sphere but does not have a well-defined boundary.
- The Sun makes one rotation through the Milky Way galaxy every ~ 250 million years.
- The total life expectancy of our Sun is estimated to be ~ 10 billion years.