<span>So far, astronomers have found more than 500 solar systemsand are discovering new ones every year. Given how many they have found in our own neighborhood of the Milky Way galaxy, scientists estimate that there may be tens of billions of solar systems in our galaxy, perhaps even as many as 100 billion.</span>
The core has the largest density, being made of iron and nickel
The mantle has an intermediate density and the crust has the lowest density.
Nuclear energy is created during a fission or fusion, and is typically used to generate electricity. Nuclear power plants use the fission or fusion reaction to create the nuclear energy, which generates heat. This heat the power plants use to transform the heat energy into electricity. Fission is where large nuclei are split into smaller nuclei. Fusion is where the small nuclei are put together to create large nuclei. These two reactions create nuclear energy.
Hello there.
<span>While others made steps toward inventing the printing press, Gutenberg is traditionally credited with this invention.
True</span>
