The solar system - its (and humanity's) future. Page 1 here
1
The formation and evolution of the Solar System began 4.6
billion years ago with the gravitational collapse of a small
part of a giant molecular cloud.
2
In roughly 5 billion years, the Sun will cool and expand
outward to many times its current diameter *, ...
3
Some planets will be destroyed, others ejected into
interstellar space.
4
Ultimately, over the course of tens of billions of years,
it is likely that the Sun will be left with none of the
original bodies in orbit around it.
And the Earth's mankind-original bodies will have been in their own orbits long before!
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* The Sun is nearly a perfect sphere. ....
The mean radius of the sun is 432,450 miles (696,000 kilometers), which makes its diameter about 864,938 miles (1.392 million km).
You could line up 109 Earths across the face of the sun. The sun's circumference is about 2,713,406 miles (4,366,813 km).
The world is coming to an end
Video here.
One hundred billion galaxies
- According to the best estimates of astronomers there are at least one hundred billion galaxies in the observable universe.
- They've counted the galaxies in a particular region, and multiplied this up to estimate the number for the whole universe.
The Milky way
- When confronted with the topic of stars and galaxies, a question that tantalizes most humans is, “Is there other intelligent life out there?” Let’s put some numbers to it—
- As many stars as there are in our galaxy (100 – 400 billion), there are roughly an equal number of galaxies in the observable universe
- so for every star in the colossal Milky Way, there’s a whole galaxy out there.
- All together, that comes out to the typically quoted range of between 1022 and 1024 total stars, which means that for every grain of sand on every beach on Earth, there are 10,000 stars out there.
10,000,000,000,000,000,000,000,000 = 1024
Do you remember?
My very educated mother just served us nachos.
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The solar system - its (and humanity's) future.
1
The formation and evolution of the Solar System began 4.6
billion years ago with the gravitational collapse of a small
part of a giant molecular cloud.
2
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 remnant known as a
white dwarf.
3
In the far distant future, the gravity of passing
stars will gradually reduce the Sun's retinue of planets.
Some planets will be destroyed, others ejected into
interstellar space.
4
Ultimately, over the course of tens of billions of years,
it is likely that the Sun will be left with none of the
original bodies in orbit around it.
Formation of the Earth
- As the universe expanded, according to current scientific understanding, matter collected into clouds that began to condense and rotate, forming the forerunners of galaxies.
- Within galaxies, including our own Milky Way galaxy, changes in pressure caused gas and dust to form distinct clouds. In some of these clouds, where there was sufficient mass and the right forces, gravitational attraction caused the cloud to compress.
- If the mass of material in the cloud was sufficiently compressed, nuclear reactions began and a star was born.
- Some proportion of stars, including our sun, formed in the middle of a flattened spinning disk of material.
- In the case of our sun, the gas and dust within this disk collided and aggregated into small grains, and the grains formed into larger bodies called planetesimals ("very small planets"), some of which reached diameters of several hundred kilometers.
- In successive stages these planetesimals coalesced into the nine planets and their numerous satellites.
- The rocky planets, including Earth, were near the sun, and the gaseous planets were in more distant orbits. ........
- The oldest known rocks on Earth occur in northwestern Canada (3.96 billion years), but well-studied rocks nearly as old are also found in other parts of the world.
- ........
- The best estimates of Earth's age are obtained by calculating the time required for development of the observed lead isotopes in Earth's oldest lead ores.
- These estimates yield 4.54 billion years as the age of Earth and of meteorites, and hence of the solar system.
- The origins of life cannot be dated as precisely, but there is evidence that bacteria-like organisms lived on Earth 3.5 billion years ago, and they may have existed even earlier, when the first solid crust formed, almost 4 billion years ago.
- source
The Search for a New Earth
Is Humanity About To Accidentally Declare Interstellar War On Alien Civilizations?
Here on Earth, our dreams of interstellar travel have traditionally fallen into two categories:
- We go slowly, with rocket-propulsion, on a journey taking many human lifetimes.
- We go quickly, assuming we make tremendous scientific advances to travel at relativistic (near-light) speeds.
- source
