Stellar Objects Vary Far More than Seems Imaginable
No Such Thing as an Average Star
- Douglas Adams, the famous science fiction writer of The Hitchhiker’s Guide to the Galaxy trilogy (of five books), once famously said: "Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." This is generally accepted as true by most people when they look up into the night sky and feel like a freckle on the but of a tiny ant. But its not just space that is big. Some things that we think of as being big, in space, like our own Sun, can also be dwarfed by other things that are much, much larger.
- The Sun is about 865,000 miles in diameter. To put that in perspective, if you were able to drive around the Earth’s equator in your car (about 24,000 miles) at a speed of 60 miles per hour, it would take you 400 hours to complete the trip non-stop (and a lot of gasoline to boot). That’s about 17 days of non-stop driving. To drive around the circumference of the Sun at the same speed would take you 601 days, or nearly two years.
- That makes the Sun seem enormously huge. But there are other stars in space that make the Sun look like a discarded pea by comparison. One of the largest known stars so far identified is VV Cephei, with the otherwise popular astronomical classification of HD 208816. It is located in the constellation of Cepheus about a distance of around 5,000 light years from Earth, which is not necessarily our local neighborhood, but close when you consider that the Milky Way galaxy is about 100,000 light years across.
VV Cephei is estimated to be approximately 1,000 to up to 1,900 solar radii in size, or at least 1,000 times larger in diameter than our Sun, and is classified as a red supergiant. This makes it roughly one billion miles in diameter.
If it would take you about two years to drive around the circumference of our Sun in your car, non-stop, how long do you think it would take to drive around VV Cephei if you could? The journey would take approximately 1,903 years, not just a measly two years, to complete one trip around.
The star VV Cephei is so immense in fact, that if it were to take the place of our Sun in space, it would reach out to the orbital distance of Jupiter, which is about 483 million miles from the Sun or nearly half a billion miles away. Placing VV Cephei in our solar system would fill up all space for the orbits of the inner planets, including Mercury, Venus, Earth and Mars (as well as poor little Jupiter). That’s one bugger of a big star