Because they coalesced out of the soup of neutral hydrogen (and a little helium) that filled the early cosmos, these stars grew large, burned bright and blue and then died quickly, probably surviving around 100 million years, give or take. Telltale fingerprints The epoch, roughly referring to...
Thus if the Universe was very dense in its first few minutes, most of the deuterium would have been converted to helium. Deuterium is not easy to detect but recent measurements of the ratio of deuterium to hydrogen give an upper limit of about 2 × 10–5 for interstellar gas. Hydrogen ...
The equilibrium ratio of ortho- to para-hydrogen depends on temperature. At room temperature or warmer, equilibrium hydrogen gas contains about 25% of the para form and 75% of the ortho form.[30] The ortho form is an excited state, having higher energy than the para form by 1.455 kJ/...
Precision experiments at the antiproton decelerator have recently constrained the properties of the antiproton through studies in Penning traps21, 22 or with antiprotonic helium23. For example, the antiproton charge-to-mass ratio is known to agree with that of the proton to 69 parts per trillion...
Thus if the Universe was very dense in its first few minutes, most of the deuterium would have been converted to helium. Deuterium is not easy to detect but recent measurements of the ratio of deuterium to hydrogen give an upper limit of about 2 × 10–5 for interstellar gas. Hydrogen ...
The most accurate measurement of the antiproton-to-electron mass ratio is performed using two-photon spectroscopy of antiprotonic helium [22]. The experimental result gives 𝑚𝑝¯/𝑚𝑒=1836.1526736(23)mp¯/me=1836.1526736(23) which agrees within uncertainty with the proton-to-electron mas...
All SectionsA: Sustainable EnergyA1: Smart Grids and MicrogridsA2: Solar Energy and Photovoltaic SystemsA3: Wind, Wave and Tidal EnergyA4: Bio-EnergyA5: Hydrogen EnergyB: Energy and EnvironmentB1: Energy and Climate ChangeB2: Clean EnergyB3: Carbon Emission and UtilizationB4: Nuclear EnergyC: En...