The ages of about 70 meteorites that have struck Earth have been studied and found to be 4.5 billion years old.
The best estimate for Earth's age is 4.5 billion years because the meteorites were formed at the same time as our solar system.
That age is the wavelength of light.
The nucleus of a uranium atom might undergo a type of decay called beta decay if 100 is incorporated into it.
A new element with atomic number 93 would be created for the first time.
The experiment detected the emission of particles.
His results were not conclusive.
He could not say with certainty that he had examined the products to determine their composition.
Three researchers in Germany--Lise Meitner (1878-1968), Fritz Strassmann (1902-1980) and Otto Hahn (1879-1968)--repeated Fermi's experiments and then performed careful chemical analysis of the products.
The element with an atomic number is named meitnerium in honor of Lise Meitner.
The nucleus of the atom was divided into smaller pieces.
The process emits a lot of energy.
Less than 1% of all naturally occurring uranium is U-235, which is the initial atom.
U-238 does not undergo fission.
There is a chance that three other U-235 atoms could be initiated into fission by the process.
This self-amplifying reaction can produce a lot of energy.
The energy is harnessed in an atomic bomb.
The Manhattan Project and Meitner determined that U-235 could undergo nuclear Fearing that Nazi Germany would develop a bomb based on nuclear fission, several U.S.
Franklin Roosevelt was encouraged by Einstein's letter to fund research for a bomb.
Roosevelt was persuaded by Einstein's letter, and in 1941 he began the most expensive scientific project ever attempted.
The project was led by a Physicist at a high security research facility in New Mexico.
On July 16, 1945, the United States blew up the world's first nuclear weapon at a test site in New Mexico.
The first atomic bomb exploded with a force equivalent to 18,000 tons of dynamite.
The United States used an atomic bomb on Japan.
Two bombs were dropped on Nagasaki and Hiroshima.
The bombs killed 200,000 people and led to Japan's surrender.
On July 16, 1945, in the New Mexico desert, the world's first atomic bomb was exploded.
The power of 18,000 tons of dynamite was generated using nuclear power.
Nuclear reactions generate a lot of energy.
A nuclear bomb releases energy at once.
The energy can be used for peaceful purposes.
Nuclear fission produces 70% of the electricity in some countries.
Imagine a nuclear-powered car that releases a lot of energy.
The fuel for the car would be a cylinder about the size of a pencil.
About 1000 twenty-gallon tanks of gasoline are equivalent to the energy content of the uranium cylinder.
If you refuel your car once a week, it could go 1000 weeks before you have to replace it.
Nuclear-powered electricity generation plants can produce a lot of electricity from a small amount of fuel.
Plants that exploit the heat created by fission use it to boil water and make steam, which then turns the turbine on a generator to produce electricity.
The core of a nuclear power plant is made of U-235, which creates heat and steam.
The control rods are raised or lowered.
The core consists of fuel rods enriched to 3.5% U-235 and retractable control rods.
The chain reaction can occur when the control rods are not in the fuel rod assembly.
When the control rods are fully inserted into the fuel assembly, they shut down the chain reaction.
The operator can increase or decrease the rate of fission with the help of the control rods.
The amount of heat needed for electricity generation is controlled in this way.
In the event of a power failure, the control rods drop into the fuel rod assembly.
A typical nuclear power plant uses 50 kilogrammes of fuel per day to generate electricity for a city of one million people.
A coal-burning power plant uses more fuel to generate the same amount of electricity.
Air pollution and greenhouse gases are not generated by a nuclear power plant.
Coalburning power plants emit pollutants such as carbon monoxide, nitrogen oxides, and sulfur oxides.
Coal-burning power plants emit carbon dioxide.
Nuclear power generation has some problems.
Nuclear accidents are the most dangerous among them.
In a nuclear power plant, the fission reaction can get out of hand.
The Chernobyl Nuclear Power Plant in the former Soviet Union and the Fukushima Daiichi Nuclear Power Plant in Japan are the most famous examples of this.
Operators of the plant performed an experiment in 1986 to reduce maintenance costs.
In order to perform the experiment, they had to destroy the reactor core in Chernobyl.
The experiment failed because disas overheated and exploded.
The nuclear core overheated and began to part of the containment structure.
The accident caused 31 deaths and a fire that scattered radio release of radioactive nuclides into the environment, forcing the government active debris into the atmosphere.
The accident was not a nuclear detonation.
The fuel used in the United States for electricity generation is not enriched enough in U-235 to make it suitable for detonation.
Nuclear power plants in the U.S. have additional safety features that can't burn in the same way as accidents.
Nuclear power plants in the U.S. have large Chernobyl core.
The cooling system pumps at the coastal plant failed after the 9.1 magnitude earthquake caused a wave to flood the plant.
Three of the nuclear cores within the plant overheated and experienced a partial meltdown, in which the fuel becomes so hot that it melts.
The accident was worsened by the loss of water in the fuel storage ponds, which caused the fuel stored in the ponds to become overheated.
In Japan, the release of radiation into the environment was lower than at Chernobyl.
No radioactivity-related deaths were reported at the plant.
The site will be cleaned for many years.
Waste disposal is a problem associated with nuclear power.
Although the amount of nuclear fuel used in electricity generation is small compared to other fuels, some of the products of the reaction are radioactive and have long half-lives.
Nuclear waste is stored at the nuclear power plants in the United States.
A single permanent disposal site was being developed in Nevada.
The Blue Ribbon Commission on America's Nuclear Future was formed in 2010 after the Obama administration halted the development of this project.
Several important recommendations have been made by the committee.
There is a temporary above-ground storage facility and a permanent underground facility.
The committee has not made a decision regarding the location of the storage facility.