Astrophysics: Difference between revisions
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*the role of active galactic nuclei in limiting the growth of galaxies. | *the role of active galactic nuclei in limiting the growth of galaxies. | ||
===CMB (cosmic microwave background radiation)=== | ===CMB (cosmic microwave background radiation)=== | ||
===Cosmic rays=== | ===Cosmic rays=== | ||
===Astroparticles=== | ===Astroparticles=== | ||
Astroparticles are particles that are found in the universe. The study of astroparticles, '''astroparticle physics''', is a multidisciplinary field that involves particle physics, astronomy, astrophysics and cosmology. Particle physics studies the nature of the structure of matter and fundamental laws governing their interactions, basically astroparticle physics studies the smallest aspects of the universe. Astronomy and astrophysics study the universe on a larger scale from its origin and evolution since the Big Bang. Cosmology in turn links the theories of particle physics with theories of the Universe at its earliest moments. <ref name=ASPERAAstroparticle>[http://www.aspera-eu.org/index.php?option=com_content&task=section&id=2&Itemid=68 Astroparticles] ASPERA (Astroparticle EraNet)</ref><ref> ASPERA is a consortium of European countries (France, Belgium, The Czech Republic, Centre Européen pour la Recherche Nucléaire (CERN), Germany, Greece, Italy, The Netherlands, Portugal, Spain, Sweden, Switzerland, and the United Kingdom) that coordinate and fund astroparticle physics. [http://www.aspera-eu.org/index.php?option=com_content&task=section&id=1&Itemid=4 ASPERA]</ref> | Astroparticles are particles that are found in the universe. The study of astroparticles, '''astroparticle physics''', is a multidisciplinary field that involves particle physics, astronomy, astrophysics and cosmology. Particle physics studies the nature of the structure of matter and fundamental laws governing their interactions, basically astroparticle physics studies the smallest aspects of the universe. Astronomy and astrophysics study the universe on a larger scale from its origin and evolution since the Big Bang. Cosmology in turn links the theories of particle physics with theories of the Universe at its earliest moments. <ref name=ASPERAAstroparticle>[http://www.aspera-eu.org/index.php?option=com_content&task=section&id=2&Itemid=68 Astroparticles] ASPERA (Astroparticle EraNet)</ref><ref> ASPERA is a consortium of European countries (France, Belgium, The Czech Republic, Centre Européen pour la Recherche Nucléaire (CERN), Germany, Greece, Italy, The Netherlands, Portugal, Spain, Sweden, Switzerland, and the United Kingdom) that coordinate and fund astroparticle physics. [http://www.aspera-eu.org/index.php?option=com_content&task=section&id=1&Itemid=4 ASPERA]</ref> | ||
Astroparticle studies employ different types of facilities and appliances. Underground laboratories are used to shield experiments from the background of cosmic muons. Land based observatories (telescopes and antennas) study very high energy gamma rays, neutrinos and very high energy cosmic rays. Satellite observatories are used to study high energy gamma rays, cosmic rays and gravitational waves.<ref name=ASPERAAstroparticle/> | Astroparticle studies employ different types of facilities and appliances. Underground laboratories to study neutrinos and dark matter are used to shield experiments from the background of cosmic muons. Land based observatories (telescopes and antennas) study very high energy gamma rays, neutrinos and very high energy cosmic rays. Satellite observatories are used to study high energy gamma rays, cosmic rays and gravitational waves.<ref name=ASPERAAstroparticle/> | ||
====Neutrinos==== | |||
Neutrinos are the second most abundant particles in the universe.<ref>Photons, light particles, are the most abundant particles in the universe. </ref> Neutrinos are produced in nuclear reactions occurring within stars. Neutrinos can also be artificially produced in high-energy collisions. Neutrinos bombard the earth constatantly in vast numbers. Each square centimetre of the human body is traversed by 60 billion neutrinos per second.<ref name=ASPERANeutrino>[http://www.aspera-eu.org/index.php?option=com_content&task=view&id=175&Itemid=98 First neutrino from CERN detected in OPERA</ref> | |||
Neutrinos are not charged particles, so they don’t interact with matter through the electromagnetic force. They do not even interact through the strong force that holds together the nucleus of an atom. Neutrinos can only be affected by other particles through the weak force (e.g. in the nuclear fusion in the stars). Becasue they do not react readily, they can pass through almost any kind and thickness of matter without leaving any traces without a deviation in their direction of motion they have had since the instant of their origin.<ref name=ASPERANeutrino/> | |||
There are three types or ''flavours'' of neutrinos: electronic, muonic or tauonic. A neutrino can oscillate from one flavour into another over long distances. <ref name=ASPERANeutrino/> | |||
Flavour oscillation may demonstrate that neutrinos do in fact have mass. Given their abundance, it is possible that neutrinos may have been invovled in some types of symmetry changes or breaks, such as the matter-antimatter ratio, believed to be very close in the early stages of the universe but matter now has an overwhelming higher ratio to ani-matter. <ref name=ASPERANeutrino/> | |||
===Black holes=== | ===Black holes=== | ||
Revision as of 16:19, 3 January 2008
Astrophysics is a hybrid of Physics and Astronomy that attempts to explain the physical workings of the celestial objects and phenomena. Astrophysics has two subdivisions: theoretical, and applied or experimental.
Research focus
Research in astrophysics addresses a great variety of topics.[1][2][3]
Stars
- formation and evolution
- magnetic field properties
- stellar convection
Stellar atmospheres
- nature of spectral analysis
- electron density[4]
The Galaxy (the Milky Way)
- interstellar gas and dust
Galaxies
- formation and evolution
- modeling the environs of galactic-centre massive black holes;
- the structure and dynamics of galactic bars;
- the flow of gas into and out of galaxies;
- the role of active galactic nuclei in limiting the growth of galaxies.
CMB (cosmic microwave background radiation)
Cosmic rays
Astroparticles
Astroparticles are particles that are found in the universe. The study of astroparticles, astroparticle physics, is a multidisciplinary field that involves particle physics, astronomy, astrophysics and cosmology. Particle physics studies the nature of the structure of matter and fundamental laws governing their interactions, basically astroparticle physics studies the smallest aspects of the universe. Astronomy and astrophysics study the universe on a larger scale from its origin and evolution since the Big Bang. Cosmology in turn links the theories of particle physics with theories of the Universe at its earliest moments. [5][6]
Astroparticle studies employ different types of facilities and appliances. Underground laboratories to study neutrinos and dark matter are used to shield experiments from the background of cosmic muons. Land based observatories (telescopes and antennas) study very high energy gamma rays, neutrinos and very high energy cosmic rays. Satellite observatories are used to study high energy gamma rays, cosmic rays and gravitational waves.[5]
Neutrinos
Neutrinos are the second most abundant particles in the universe.[7] Neutrinos are produced in nuclear reactions occurring within stars. Neutrinos can also be artificially produced in high-energy collisions. Neutrinos bombard the earth constatantly in vast numbers. Each square centimetre of the human body is traversed by 60 billion neutrinos per second.[8]
Neutrinos are not charged particles, so they don’t interact with matter through the electromagnetic force. They do not even interact through the strong force that holds together the nucleus of an atom. Neutrinos can only be affected by other particles through the weak force (e.g. in the nuclear fusion in the stars). Becasue they do not react readily, they can pass through almost any kind and thickness of matter without leaving any traces without a deviation in their direction of motion they have had since the instant of their origin.[8]
There are three types or flavours of neutrinos: electronic, muonic or tauonic. A neutrino can oscillate from one flavour into another over long distances. [8]
Flavour oscillation may demonstrate that neutrinos do in fact have mass. Given their abundance, it is possible that neutrinos may have been invovled in some types of symmetry changes or breaks, such as the matter-antimatter ratio, believed to be very close in the early stages of the universe but matter now has an overwhelming higher ratio to ani-matter. [8]
Black holes
Dark matter
Dark energy
Dark energy is a theoretical energy which exerts a negative attraction or opposes the positive attraction of matter and causes the universe to expand.[9][10]
A current line of study is surveying the distribution of galaxies in the cosmos. The distribution pattern is compared to the miniscule temperature fluctuations in the cosmic microwave background. Theoretically acoustic waves moving through the early universe created temperature fluctuations, and the fluctuations are correlated to regions of the universe that had slightly higher and lower densities. These regions of varied density are believed to have influenced how matter eventually clumped together through gravitational influences and thereby formed galaxy clusters. Comparing clumping in the early universe to clumping being observed now may possibly allow researchers to ascertain the role dark energy has played in cosmic evolution.[11]
Astrochemistry
Astrochemistry involves the study of the role of the chemical bond and organic chemistry in nature on a cosmic scale. Over 140 molecules have been identified in the interstellar gas and circumstellar shells. To date the largest is a carbon chain with 13 atoms and a molecular weight of 147.[12]
Inflation
Inflation refers to the expansion of the universe, its velocity and whether or not it is slowing or gaining in speed.[9] The Supernova Acceleration Probe (SNAP) is a space observtory planned for possible construction and launch by 2020. It is designed to measure the expansion of the Universe and determine the nature of Dark Energy which current theory holds is accelerating cosmological expansion.[13]
Curvature
Curvature refers to the shape of the universe.[9]
Notes
- ↑ Theoretical astrophysics Oxford Physics, Oxford University
- ↑ CfA Research Harvard-Smithsonian Center for Astrophysics
- ↑ [1] Goddard Space Flight Center Astrophysics Sciecne Division
- ↑ Degenerate electron pressure Swineburn University, Centre for Astrophysics and Supercomputing
- ↑ 5.0 5.1 Astroparticles ASPERA (Astroparticle EraNet)
- ↑ ASPERA is a consortium of European countries (France, Belgium, The Czech Republic, Centre Européen pour la Recherche Nucléaire (CERN), Germany, Greece, Italy, The Netherlands, Portugal, Spain, Sweden, Switzerland, and the United Kingdom) that coordinate and fund astroparticle physics. ASPERA
- ↑ Photons, light particles, are the most abundant particles in the universe.
- ↑ 8.0 8.1 8.2 8.3 [http://www.aspera-eu.org/index.php?option=com_content&task=view&id=175&Itemid=98 First neutrino from CERN detected in OPERA
- ↑ 9.0 9.1 9.2 Dark energy fills the cosmos Preuss, Paul (1999). Science Beat. The Berkeley Lab, U.S. Department of Energy.
- ↑ [2] Cosmology with dark energy decaying through its chemical-potential contribution. Besprovsvany, J., Instituto de Física, Universidad Nacional Autónoma de México (2007). Journal of Physics A: Mathematical and Theoretical, 40 7099-7104
- ↑ Advanced Dark Energy Physics Telescope Beyond Einstein. National Aeronautics and Space Administration
- ↑ Astrochemistry Harvard-Smithsonian Center for Astrophysics
- ↑ SuperNova Acceleration Probe Lawrence Berkeley National Lab