Using fragments of radioactive glass picked up from the site of the first nuclear bomb explosion in the United States, scientists are trying to explain the mystery behind the formation of the moon and the properties of lunar rocks. The study by researchers from the Scripps Institution of Oceanography at the University of California - San Diego used materials from the Trinity test site in New Mexico to show that the explosion could be similar to a collision between proto-Earth and a Mars-sized object 4.5 billion years ago. Read more.
An oversight in a radioisotope dating technique used to date everything from meteorites to geologic samples means that scientists have likely overestimated the age of many samples, according to new research from North Carolina State University.
To conduct radioisotope dating, scientists evaluate the concentration of isotopes in a material. The number of protons in an atom determines which element it is, while the number of neutrons determines which isotope it is. For example, strontium-86 has 38 protons and 48 neutrons, whereas strontium-87 has 38 protons and 49 neutrons. Radioactive elements, such as rubidium-87 (but not strontium-86 or strontium-87), decay over time. By evaluating the concentrations of all of these isotopes in a rock sample, scientists can determine what its original make-up of strontium and rubidium were. Then, by assessing the isotope concentrations of rubidium and strontium, scientists can back-calculate to determine when the rock was formed. Read more.
Black carbon accelerates climate change by darkening snow and ice to make them warm faster.
There is more soot in remote Siberia than at the edge of densely populated Europe, even though there are hardly any people there, the first in-depth study of black carbon in the region has found. In Tiksi, a small town in an isolated region of north-eastern Siberia, the levels of black carbon emitted by traffic is at higher levels than in Sweden, according to the two-year study published in the journal PNAS. Before this study, black carbon levels in this part of Russia were a blank spot on the map.
Black carbon pollution is a problem in the Arctic because it amplifies the effects of climate change. When black soot lies on white snow it increases the absorption of heat of the snow, which would otherwise be reflected back out into space. This increases the rate at which the permafrost in northern Siberia is melting. Read more.
The moon may carry material produced by life from Earth dating back to when plants first filled the planet’s air with oxygen, according to study of data from a Japanese lunar orbiter. A team led by Kentaro Terada of Osaka University looked at data from the Selenological and Engineering Explorer, better known as Kaguya. The researchers found that a certain kind of oxygen isotope was present in the lunar soil, an isotope that occurs on Earth.
Almost all of the oxygen in Earth’s atmosphere for the last 2 and a half billion years came from photosynthesis. That means the moon’s rocks have been picking up small amounts of oxygen from living things on Earth; the moon is “contaminated” with the waste products of plants, the researchers said. Read more.
In the sun and other fusion plasmas, atoms of hydrogen and its isotopes are the fuel. Plasmas are gases that are so hot that electrons are knocked free of the atom, making the atoms electrically charged ions. The un-ionized atoms are called neutrals. On earth, accurately measuring neutral hydrogen concentration in plasmas could offer insights into future fusion experiments and impact the design of a future fusion-based energy source. To measure the hydrogen density, scientists need to use a calibrated measurement method. They use krypton gas, which absorbs two chunks of light energy at the same time (photons) and in turn emits another photon. The problem is that the light emitted is not at the right wavelength for accurate hydrogen density measurements. In this study, scientists discovered that xenon atoms emit light at a wavelength that calibrates well with hydrogen and improves the measurements of neutral hydrogen density. Read more.