-- Earth is one planet is a "Solar System", that consists of everything
that's gravitationally hooked to the Sun ... one star. This system contains
7 other other significant planets, more than 100 of their moons, and huge
numbers of comets, asteroids, dwarf planets, and countless bodies in a
giant shell that are so small and so far away that we can only see a few
of them so far. Every one of these items orbits the sun. The ones that
are farthest out may take thousands of years to complete one orbit.
That's the 'kingdom' of ONE star ... the sun.
-- It's very likely that there are similar gatherings of different-size objects
around MOST stars ... maybe ALL stars. Those objects are tremendously
difficult for us to see. We're just beginning to be able to see the most massive
planets that go with other stars, and already, something like a thousand of them
have been discovered. We know that they're there, but we can't see things like
their actual size or surface markings yet.
-- Stars are clumped in gatherings of several billion, called 'galaxies'.
Our sun is one of an estimated 300 to 400 billion stars in one galaxy,
which we call the "Milky Way Galaxy".
-- Astronomers estimate that there are billions of other galaxies.
So there are billions of billions of other stars, and most of them may
have several planets.
That's an awful lot of OTHER physical systems out there, that contain
other planets and moons.
Having trouble wrapping your mind around all of that ? Don't worry,
you're not the only one. It's easy for us to talk about it, but impossible
for our minds to actually understand it. It's just too big.
They give us informations about our ancestors and how did they live and what did they do and than compare it to present way's of life.
The type of rock that's formed is igneous
<h2>
The End of Trans-Saharan Trade Routes:</h2>
Explanation:
The factors that led to the end of trans-Saharan trade routes are:
- Civil unrest due to collapse of the Songhay Empire, the Timbuktu, by the Morracans in 1591
- The extreme desert conditions like extreme climates, excessive heat, lack of water and food etc made the travel logistics very tough. This made people opt for other transport systems
- Huge advancements made in maritime travel
- Exploration of West African trade routes
- Economic, political and social changes which led to the end of trans-Saharan trade routes
<span>Direct election of senators to Congress occurred because of the 17th constitutional amendment.</span>
