The material in the disks is thought to consist mainly of gas (99% by mass), predominantly molecular hydrogen and helium with trace amounts of CO and other molecules, and small dust particles (1% by mass).

Protoplanetary Disk. A rotating circumstellar disk of dense gas surrounding a young newly formed star. It is thought that planets are eventually formed from the gas and dust within the protoplanetary disk.

Our solar system began forming about 4.6 billion years ago within a concentration of interstellar dust and hydrogen gas called a molecular cloud. The cloud contracted under its own gravity and our proto-Sun formed in the hot dense center. The remainder of the cloud formed a swirling disk called the solar nebula.

Jovian planets do not have solid surfaces. They are sometimes called gas giants because they are large and made mostly of gases. The atmospheres of the Jovian planets in our solar system are made mostly of hydrogen and helium. Compounds containing hydrogen, such as water, ammonia, and methane, are also present.

Pluto’s position in the solar system would tend to cause it to be classified as a Jovian planet, but it is even smaller than terrestrial planets. Although it is even smaller than terrestrial planets, its average density is closer to the giant outer (Jovian) planets.

Pluto is different from the other planets, because it’s not classified as a gas giant planet, or a terrestrial planet. The reason pluto is not considered a either of these is, because it has too small of a density to be considered a terrestrial planet, and is made up of rock, and ice, and no gas.

Although there are many icy objects in the Solar System, there are no known ice planets (though Pluto was considered an ice planet until its reclassification in 2006). If a 9th planet suggested in 2016 is found, it will be an ice planet of many times the Earth’s mass with a surface temperature potentially under 70K.

Is Pluto a terrestrial planet or is it a gas giant? Answer 1: Pluto is NEITHER. Terrestrial planets are made up (mostly) of metal (iron) and rocks (silicates).

Lying 30 to 50 times as far from the sun as Earth, Pluto’s composition bears a greater resemblance to the rocky terrestrial planets than the gas giants that are its neighbors. New Horizons revealed that the surface of the dwarf planet appears to be dominated by nitrogen ice, with methane and carbon mixed in.

Is there plutonium on Pluto? No. Neither is there neptunium on Neptune. There is certainly a lot of uranium in the core of Uranus.

5 grams of plutonium to die immediately, compared to about . 1 grams of cyanide. The plutonium at Fukushima isn’t in the air, but inhaling about 20 milligrams of plutonium would probably kill you within a few months. External exposure carries almost no risk.

This is the reason why Pu-238 is so expensive – making it requires two bouts of irradiation (the first long enough to produce the Pu-241), enough time for all of the radioactive decays to transform plutonium into americium and the americium into neptunium, and several steps of chemical processing to isolate the various …

Plutonium-239 is a fissionable isotope and can be used to make a nuclear fission bomb similar to that produced with uranium-235. The bomb which was dropped at Nagasaki was a plutonium bomb. Not enough Pu-239 exists in nature to make a major weapons supply, but it is easily produced in breeder reactors.

In practice, bombs do not contain hundreds of tons of uranium or plutonium. Instead, typically (in a modern weapon) the core of a weapon contains only about 5 kilograms of plutonium, of which only 2 to 2.5 kilograms, representing 40 to 50 kilotons of energy, undergoes fission before the core blows itself apart.

A super-powered neutrino generator could in theory be used to instantly destroy nuclear weapons anywhere on the planet, according to a team of Japanese scientists. If it was ever built, a state could use the device to obliterate the nuclear arsenal of its enemy by firing a beam of neutrinos straight through the Earth.

Neutron bomb, also called enhanced radiation warhead, specialized type of nuclear weapon that would produce minimal blast and heat but would release large amounts of lethal radiation.

Edward Teller