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Neptunium has also been used in detectors of high-energy neutrons. The longest-lived isotope of neptunium, neptunium-237, is a by-product of nuclear reactors and plutonium production. This isotope, and the isotope neptunium-239, are also found in trace amounts in uranium ores due to neutron capture reactions and beta decay. [7]
The timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. Each object is listed in chronological order of its discovery (multiple dates occur when the moments of imaging, observation, and publication differ), identified through its various designations (including temporary and permanent schemes), and the ...
In 1868 Jules Janssen and Norman Lockyer discovered a new element in the Sun unknown on Earth, helium, which currently comprises 23.8% of the mass in the solar photosphere. [34] As of today, spectroscopes are an important tool to know about the chemical composition of the celestial bodies.
For Earth Day on April 22, interesting facts including who invented it, why it's on that date, and how it turned into a global movement. ... Stash of Roman-era coins buried 2,000 years ago found ...
The 1990 Earth Day demonstration included efforts from about 200 million people in 141 countries, according to the Earth Day Network. Earth Day has inspired countries to start environmentally ...
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Einsteinium and fermium were discovered by a team of scientists led by Albert Ghiorso in 1952 while studying the composition of radioactive debris from the detonation of the first hydrogen bomb. [19] The isotopes synthesized were einsteinium-253, with a half-life of 20.5 days, and fermium-255 , with a half-life of about 20 hours.
Its sidereal rotation period (day) is roughly 16.11 hours. [12] Because its axial tilt is comparable to Earth's, the variation in the length of its day over the course of its long year is not any more extreme. Because Neptune is not a solid body, its atmosphere undergoes differential rotation. The wide equatorial zone rotates with a period of ...