- Joined
- Feb 11, 2009
- Messages
- 23,143
- Reaction score
- 18,821
- Location
- NJ (The nice part)
- Guild Total
- 112
Take a look at this pic. You've probably seen it in my Eclipse threads:
Compared to the Earth, the sun is really, REALLY big. How big? If you saw totality then you probably noticed the giant pink spot on the bottom. Here's my pic:
To put that in perspective, the Earth is 1/108th the diameter of the sun. Here's my representation of that scale. The blue dot is the size of Earth:
As you probably know, the Earth is 93 million miles from the sun. This varies based on its position in orbit, but it's really, really far away. This distance is called one Astronomical Unit or AU.
In some of my science and photography threads I've mentioned the Inverse Square Law which states that energy decreases with the inverse square of the distance. In other words every time you double the distance from an energy source you 1/4 the energy received. Triple the distance and you get 1/9th the energy, and so-on.
Think about standing in front of a camp fire or a fireplace with a roaring fire and think about how if you take even a step or two back you can feel the dramatic difference in the heat from the fire. A roaring fire in a fireplace feels very different close up than it does just a few feet away in the same room. This is the inverse square law in action.
Now lets go back to the sun. The sun is a self-sustaining fusion reactor that pumps out an incredible amount of energy in the form of full-spectrum radiation including infra-red and ultra-violet. And it's 93,000,000 miles away. Yet on a clear day if you stand outside and hold your hands up to the sun you can feel its heat. Remembering that Inverse Square Law, imagine what the energy output is for that enormous ball of fusion 93M miles away to warm your hands here on Earth.
And it gets weirder! The sun is made of mostly hydrogen and helium. Hydrogen is the lightest element there is with only one electron so of course it's lighter than helium which has two. Think about a helium balloon: If you pop it, the helium rushes up since it's so much lighter than air and dissipates into the surrounding air in a split second. Gases expand to fill their container, and helium without a container just stops being a cloud of helium and becomes a bunch of atoms spread all around until they rise up to the upper atmosphere. Helium is also very stable so it doesn't react with other elements. Hydrogen is even lighter.
Now imagine billions of years ago that there's so much hydrogen floating around in space that it starts to attract all the other hydrogen nearby due to gravity. Imagine that there is SO much hydrogen that the gravity forms it all into a ball which gets bigger and bigger with more and more hydrogen attracted until the hydrogen is under so much pressure from its own gravity that the atoms mash together and fuse because of the insane pressure and heat.
BAM - a star is born.
It is estimated that out sun is ~4 billion years old and it will burn for ~4 billion more. And it's a ball of hydrogen that's so big and so dense that it keeps planets, asteroids, and dust orbiting it up to 5,000 - maybe even 200,000 AU away.
Oh - and back to that pic with the blue dot. That solar prominence is likely longer than the distance between the Earth and the moon.
Edit: Math error fixed.
Compared to the Earth, the sun is really, REALLY big. How big? If you saw totality then you probably noticed the giant pink spot on the bottom. Here's my pic:
To put that in perspective, the Earth is 1/108th the diameter of the sun. Here's my representation of that scale. The blue dot is the size of Earth:
As you probably know, the Earth is 93 million miles from the sun. This varies based on its position in orbit, but it's really, really far away. This distance is called one Astronomical Unit or AU.
In some of my science and photography threads I've mentioned the Inverse Square Law which states that energy decreases with the inverse square of the distance. In other words every time you double the distance from an energy source you 1/4 the energy received. Triple the distance and you get 1/9th the energy, and so-on.
Think about standing in front of a camp fire or a fireplace with a roaring fire and think about how if you take even a step or two back you can feel the dramatic difference in the heat from the fire. A roaring fire in a fireplace feels very different close up than it does just a few feet away in the same room. This is the inverse square law in action.
Now lets go back to the sun. The sun is a self-sustaining fusion reactor that pumps out an incredible amount of energy in the form of full-spectrum radiation including infra-red and ultra-violet. And it's 93,000,000 miles away. Yet on a clear day if you stand outside and hold your hands up to the sun you can feel its heat. Remembering that Inverse Square Law, imagine what the energy output is for that enormous ball of fusion 93M miles away to warm your hands here on Earth.
And it gets weirder! The sun is made of mostly hydrogen and helium. Hydrogen is the lightest element there is with only one electron so of course it's lighter than helium which has two. Think about a helium balloon: If you pop it, the helium rushes up since it's so much lighter than air and dissipates into the surrounding air in a split second. Gases expand to fill their container, and helium without a container just stops being a cloud of helium and becomes a bunch of atoms spread all around until they rise up to the upper atmosphere. Helium is also very stable so it doesn't react with other elements. Hydrogen is even lighter.
Now imagine billions of years ago that there's so much hydrogen floating around in space that it starts to attract all the other hydrogen nearby due to gravity. Imagine that there is SO much hydrogen that the gravity forms it all into a ball which gets bigger and bigger with more and more hydrogen attracted until the hydrogen is under so much pressure from its own gravity that the atoms mash together and fuse because of the insane pressure and heat.
BAM - a star is born.
It is estimated that out sun is ~4 billion years old and it will burn for ~4 billion more. And it's a ball of hydrogen that's so big and so dense that it keeps planets, asteroids, and dust orbiting it up to 5,000 - maybe even 200,000 AU away.
Oh - and back to that pic with the blue dot. That solar prominence is likely longer than the distance between the Earth and the moon.
Edit: Math error fixed.
Last edited:
