Hydrogen
Hydrogen (atomic symbol H) is the simplest atom in the Universe. It consists of one proton and one electron.
Hydrogen (pronounced /ˈhaɪdrÉ™dÊ'É™n/[1]) is the chemical element with atomic number 1. It is represented by the symbol H.
A hydrogen cloud (2372) A hydrogen cloud is a nebula composed of hydrogen.
Is hydrogen necessary for the creation of stars. Can stars be born out of the fusion of heavier elements? What happens when molecular hydrogen in the Universe is exhausted or get to be very rare ?
The Answer ...
Definition: hydrogen: The lightest and most abundant element. A hydrogen atom consists of one proton and one electron. Hydrogen composes about 75 percent of the Sun but only a tiny fraction of the Earth.
Hydrogen
Wikipedia, the free encyclopedia - Cite This Source
Hydrogen (IPA: /ˈhaɪdrÉ™(ÊŠ)dÊ'É™n/), is a chemical element represented by the symbol H and an atomic number of 1.
Neutral hydrogen atoms emit electromagnetic radiation at a wavelength of 21.1cm as a result of the atom's single electron changing from having spin parallel to that of the nucleus, to having spin antiparallel to that of the nucleus.
hydrogen shell burning Fusion of hydrogen in a shell that is driven by contraction and heating of the helium core.
HYDROGEN H Z = 1
This element was discovered by Cavendish in London in 1766. Its name alludes to the fact that water is generatod when hydrogen burns in air.
Ionization energies
HI 13.6 eV.
Hydrogen cloud--A huge section of hydrogen.
Dust tail--The most visible part of the comet made of dust particles from the nucleus. Dust tails are very long and smoke-like.
hydrogen
the simplest and lightest element; usually consists of just a single proton and electron; about 90 percent of the atoms in the universe are hydrogen
hypered film ...
Hydrogen peroxide Used as a 6% (20Vols) solution to clean and deodorize wounds and ulcers. More common 1% or 2% solutions of hydrogen peroxide have been used in household first aid for scrapes, etc.
HYDROGEN AND HELIUM BURNING
Let's begin by reviewing the reactions leading to heavy-element production at various stages of stellar evolution. Stellar nucleosynthesis begins with the proton"proton chain studied in Chapter 16.
Hydrogen Cloud
Some of the water vapor ejected in the jets from the nucleus is dissociated by solar ultraviolet light into oxygen and hydrogen. The hydrogen forms a huge cloud around the comet that can be tens of millions of kilometers across.
HYDROGEN BOND - Type of attractive intermolecular force that exists between two partial electric charges of opposite polarity.
Hydrogen: An element with atomic number 1; symbol: H. It is the most abundant element in the solar system, making up 90 percent of the Sun. Hydrogen, carbon, nitrogen, and oxygen are essential for life.
hydrogen
The lightest and most abundant element. Average stars like the Sun are composed mostly of hydrogen, which is being converted into helium.
I ...
Hydrogen Alpha - A specific emission line of ionized hydrogen at 656.3 nanometers. Hydrogen-alpha emissions are responsible for the red color in emission nebulae.
Hydrogen
(a) Element that is the lightest and the most abundant in the Universe. Its atom comprises one proton and one electron.
Hydrogen bomb A type of extremely large nuclear bomb, releasing fusion energy of heavy hydrogen (or in later versions, lithium) as well as fission energy of plutonium and uranium.
HYDROGEN
Hydrogen is the element with the atomic number 1. It is the lightest element and the most abundant in the universe. Its nucleus is a single proton which is orbited by one electron.
21-cm Hydrogen Line: Radio emission of a very specific radio frequency of 1420 MHz by a neutral hydrogen atom when its single electron flips, emitting a single photon of energy with a wavelength of 21 centimeters.
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Hydrogen is undergoing fusion in the core, which produces helium and energy. The star is happily doing this for 90% of its life, which is the amount of time it spends on the Main Sequence.
Hydrogen importation could also be done for atmospheric and hydrospheric engineering. Depending on the level of carbon dioxide in the atmosphere, importation and reaction of hydrogen would produce heat, water and graphite via the Bosch reaction.
Hydrogen-deuterium absorption cell channel: measures relative abundance of hydrogen and deuterium from Lyman-Alpha emission, using resonance absorption cells. Channel electron multiplier detector records photons not absorbed in cells.
Hydrogen fusing stars which fall on a single line in the . The lifetime of a main sequence star of mass M and luminosity L is given by
From the main sequence
where is the mass of the and its luminosity, it follows that ...
Hydrogen fusion begins : star is "born"
evolutionary tracks on H-R diagram
Zero Age Main Sequence (ZAMS)
location on MS mass dependent (O high, M low)
formation time mass dependent (O short, M long) ...
Hydrogen Cloud
huge sparse envelope of neutral hydrogen
millions of km in diameter
Best known is Comet Halley, but Shoemaker-Levy 9 was a big media hit for a week in the summer of 1994 as it broke apart and pieces of it slammed into Jupiter.
Hydrogen is ionized by absorption of Lyman continuum photons (l « 912 Å, energy above 13.6 eV). The line radiation we detect arises from recombination of the electrons so released with another proton, and a cascade toward the ground state.
Hydrogen Energy Levels is a simple applet demonstrating the use of the Bohr equation to calculate the energy levels of a hydrogen atom. It shows an energy level diagram vertically from infinity to the ground state.
Hydrogen-atmosphere variable white dwarf (Spectral Class DAV4.3).
How Far Away:
50 light years.
Hydrogen The most common gas in the universe. Each atom of hydrogen contains one proton.
A.. B.. C.. D.. E.. F.. G.. H.. I.. J.. K.. L.. M..
N.. O.. P.. Q.. R.. S.. T.. U.. V.. W.. X.. Y.. Z..
Hydrogen (H) lines strongest for A0 stars, decreasing for other A's.
Sirius, Vega
F ...
Hydrogen is the most abundant element in the universe so we should be able to detect lots of it. However, most of it will be at very low temperatures, too low to be ionized or to have many atoms with electrons up in the higher energy orbits.
hydrogen -- no longer used because of the high flammability. See Hindenburg disaster
helium ...
hydrogen - (n.)
simplest atom, consisting only of one proton and one electron; the most abundant element in the Universe.
hypotheses - (n.) ...
Hydrogen
An element consisting of one electron and one proton. Hydrogen is the lightest of the elements and is the building block of the universe. Stars form from massive clouds of hydrogen gas.
The hydrogen of these opaque dark clouds exists in the form of H2 molecules. The largest nebulae of this type, the so-called giant molecular clouds, are more than a million times as massive as the Sun.
97% hydrogen,
3% helium,
.05% methane Rings
Rings are 270,000 km in diameter,
but only a few hundred meters thick.
Particles are centimeters to decameters
in size and are ice (some may be covered
with ice); there are traces of silicate ...
The hydrogen cyanide has diffused both north and sough, mixed by wave activity. Jupiter's many cloud bands carry material around the planet swiftly, but the bands do not mix easily.
Both hydrogen and helium are clear gasses, so why is the king of the planets tan and brown rather than having a clear atmosphere that would allow us to see down to its "surface' of liquid metallic hydrogen?
Even hydrogen, the bulk of the substance of Jupiter other than some helium and traces of various ices, becomes liquid in the interior of the gas planet when the pressure exerted by the weight of the upper layers exceeds four million bars.
Enough hydrogen is left in the sun's core to last another 4.5 billion years.
Metallic Hydrogen - A form of hydrogen in which the atoms have been forced into a lattice structure typical of metals.
Layers of hydrogen and helium gas surround the metallic hydrogen, and a relatively thin layer of clouds envelops the entire planet.
[9.6] THE HYDROGEN ECONOMY?
[9.7] FOOTNOTE: OTHER INDUSTRIAL CHEMICALS
[10.0] Traditional Materials ...
A form of hydrogen under high pressure that is a good electrical conductor.
Lobate Scarp
A curved cliff such as those found on Mercury.
The liquid hydrogen, combined with Jupiter's rapid 10-hour rotation, generates a magnetic field 25 times stronger than Earth's. The magnetic field, in turn, traps ions in a huge volume called the magnetosphere.
This light hydrogen gas allows Saturn's atmosphere and auroral curtains to reach much farther out than Earth's displays but the speed at which they change is comparable to some of those on Earth.
As a star's hydrogen is converted into helium, its chemical composition becomes inhomogeneous: helium-rich in the core, where the nuclear reactions occur, and more nearly pure hydrogen in the surrounding envelope.
They 'burn' hydrogen into helium in their centres during the main-sequence phase but eventually there is no hydrogen left in the centre to provide the necessary pressure to balance the inward pull of gravity.
interstellar hydrogen, 21.1 centimeters in wavelength
galactic plane
Population I stars ...
When the core hydrogen runs out, main sequence stars balloon outward to become (depending on their masses) giants or supergiants. The lower a star's birth mass, the longer it will live.
Initially, the hydrogen-fusing shell of an AGB star is responsible for most of the star's energy output.
hydrogen embrittlement (NASA Thesaurus) A decrease in fracture strength of metals due to the incorporation of hydrogen in the metal lattice.
Running out of Hydrogen
In part 1, a star was described as sort of a nuclear furnace which is held together by gravity and powered by hydrogen being fused into helium and producing heat and light.
For example, the hydrogen alpha line has a laboratory wavelength of 656.285 nm. If this spectral line in the light from a nearby star is 656.315 nm, we can calculate its receding speed as follows: ...
As the Sun burns hydrogen at its core, it releases vast amounts of atomic particles, or pieces of atoms into outer space. These atomic particles, along with the Sun's radiation create a sort of wind, known as the solar wind.
The large atomic hydrogen halo detected up to 10 kilometres from the nucleus is simply a large coma visible in ultraviolet (Lyman-alpha line).
Uranus is largely hydrogen and helium, but (like Neptune) contains higher proportions of heavy elements than Jupiter or Saturn, and is covered with clouds. Our only direct spacecraft observation of Uranus came from Voyager 2 in 1986.
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 See also: Light, Sun, Solar, Mass, Earth
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