“interstellar matter”的概念、定义、翻译、参考文献-科学参考

interstellar matter

Astronomy

The material between the stars, also called the interstellar medium. The ISM in our Galaxy consists of 99% gas and 1% fine dust particles by mass. There are also a few very energetic cosmic-ray particles. The ISM is spread very thinly, with an average density of only 1 particle/cm³. However, there are enormous variations about this average. The densest parts, with 10¹⁰ hydrogen molecules/cm³, can also be the coldest, with temperatures close to the present-day minimum set by the cosmic microwave background, 2.7 K. The hottest, ionized material has temperatures of 10⁸ K and densities of 1 particle/m³ or less. The ISM is the reservoir of matter from which new stars form in giant molecular clouds.

Space Exploration

A medium of electrons, ions, atoms, molecules, and dust grains that fills the space between stars in our own and other galaxies. Over 100 different types of molecule exist in gas clouds in our own Galaxy. Most have been detected by their radio emissions, but some have been found by the absorption lines they produce in the spectra of starlight. The most complex molecules, many of them based on carbon, are found in the dense clouds where stars are forming. They may be significant for the origin of life elsewhere in space.
It is only since the mid-twentieth century that scientists have realized that there is sufficient interstellar matter to have significant effects and that its extent largely determines the form and development of a galaxy. It is most easily observable in the radio region of the spectrum, but was first detected optically. Condensations of such matter are visible as nebulae, while over large parts of the sky interstellar matter dims, reddens, and polarizes the light of distant stars. It also causes a number of characteristic absorption lines in star spectra.
Early radio observations by US radio astronomers Karl Jansky and Grote Reber showed the general extent of interstellar matter; further observations plotted the distribution of its most abundant constituent, neutral hydrogen atoms. Later radio observations located hydroxyl, helium, water, ammonia, and many other molecules, some of them quite complex.
Interstellar matter is not smoothly distributed but occurs in dense and cold clouds. Its fundamental properties are largely determined by the hydrogen component. By mass, helium is 20–30% as abundant as hydrogen. All the other elements together do not amount to more than 3–5%.

单词	interstellar matter
释义	interstellar matter Astronomy The material between the stars, also called the interstellar medium. The ISM in our Galaxy consists of 99% gas and 1% fine dust particles by mass. There are also a few very energetic cosmic-ray particles. The ISM is spread very thinly, with an average density of only 1 particle/cm³. However, there are enormous variations about this average. The densest parts, with 10¹⁰ hydrogen molecules/cm³, can also be the coldest, with temperatures close to the present-day minimum set by the cosmic microwave background, 2.7 K. The hottest, ionized material has temperatures of 10⁸ K and densities of 1 particle/m³ or less. The ISM is the reservoir of matter from which new stars form in giant molecular clouds. Space Exploration A medium of electrons, ions, atoms, molecules, and dust grains that fills the space between stars in our own and other galaxies. Over 100 different types of molecule exist in gas clouds in our own Galaxy. Most have been detected by their radio emissions, but some have been found by the absorption lines they produce in the spectra of starlight. The most complex molecules, many of them based on carbon, are found in the dense clouds where stars are forming. They may be significant for the origin of life elsewhere in space. It is only since the mid-twentieth century that scientists have realized that there is sufficient interstellar matter to have significant effects and that its extent largely determines the form and development of a galaxy. It is most easily observable in the radio region of the spectrum, but was first detected optically. Condensations of such matter are visible as nebulae, while over large parts of the sky interstellar matter dims, reddens, and polarizes the light of distant stars. It also causes a number of characteristic absorption lines in star spectra. Early radio observations by US radio astronomers Karl Jansky and Grote Reber showed the general extent of interstellar matter; further observations plotted the distribution of its most abundant constituent, neutral hydrogen atoms. Later radio observations located hydroxyl, helium, water, ammonia, and many other molecules, some of them quite complex. Interstellar matter is not smoothly distributed but occurs in dense and cold clouds. Its fundamental properties are largely determined by the hydrogen component. By mass, helium is 20–30% as abundant as hydrogen. All the other elements together do not amount to more than 3–5%.
随便看	point kriging point load index point load tester point mass(in mechanics) point mutation point of application point of inflexion point of presence point-of-sale system point pattern analysis point process points at infinity points((change in index)) point-set topology point source point-spread function point-to-point control point-to-point line Point-to-Point Protocol point-to-point protocol point-to-point video conferencing pointwise addition pointwise convergence poise Poiseuille, Jean Louis Marie (1797–1869)