Difference between revisions of "Astrochemistry" - New World Encyclopedia

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Astrochemistry is the study of the chemical elements found in outer space, generally on larger scales than the Solar System, particularly in molecular gas clouds, and the study of their formation, interaction and destruction. As such, it represents an overlap of the disciplines of astronomy and chemistry. On the Solar System scale, the study of chemical elements is usually called cosmochemistry.

Detection of chemicals

Methods of detection

Astrochemistry involves the use of telescopes to measure various aspects of bodies in space, such as their temperature and composition. Findings from the use of spectroscopy in chemistry laboratories can be employed in determining the types of molecules in astronomical bodies (e.g. a star or an interstellar cloud). The various characteristics of molecules reveal themselves in their spectra, yielding a unique spectral representation corresponding to each type of molecule.

Limits of detection

However, there are limitations on measurements due to electromagnetic interference and, more problematic, the chemical properties of some molecules. For example, the most common molecule (H₂, hydrogen gas), does not have a dipole moment, so it is not detected by radio telescopes. Much easier to detect with radio waves, due to its strong electric dipole moment, is CO (carbon monoxide).

Molecules detected

Over a hundred molecules (including radicals and ions) have been reported so far, including a wide variety of organic compounds, such as alcohols, acids, aldehydes, and ketones. There have been claims regarding interstellar glycine, the simplest amino acid, but with considerable accompanying controversy. Research is progressing on the way interstellar and circumstellar molecules form and interact, and this research could have a profound impact on our understanding of the origin of life on Earth.

The sparseness of interstellar and interplanetary space results in some unusual chemistry, because symmetry-forbidden reactions cannot occur except on the longest of timescales. For this reason, molecules and molecular ions that are unstable on Earth can be highly abundant in space, for example the H₃⁺ ion.

Astrochemistry overlaps strongly with astrophysics and nuclear physics in characterizing the nuclear reactions that occur in stars, the consequences for stellar evolution, as well as stellar 'generations'. Indeed, the nuclear reactions in stars produce every naturally-occurring chemical element. As the stellar 'generations' advance, the mass of the newly-formed elements increases. A first-generation star uses elemental hydrogen (H) as a fuel source and produces helium (He). Hydrogen is the most abundant element, and it is the basic building block for all other elements as its nucleus has only one proton. Gravitational pull toward the center of a star creates massive amounts of heat and pressure, which cause nuclear fusion. Through this process of merging nuclear mass, heavier elements are formed. Lithium, carbon, nitrogen and oxygen are examples of elements that form in stellar fusion. After many stellar generations, very heavy elements are formed (e.g. iron and lead).

References
ISBN links support NWE through referral fees

Shaw, Andrew M. 2006. Astrochemistry: From Astronomy to Astrobiology. Chichester, England: John Wiley & Sons. ISBN 978-0470091371.

External links

Astrochemistry - division of the International Astronomical Union. Retrieved September 30, 2007.

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 '''Astrochemistry''' is the study of the [[chemical elements]] found in [[outer space]], generally on larger scales than the [[Solar System]], particularly in [[Molecular cloud|molecular gas cloud]]s, and the study of their formation, interaction and destruction. As such, it represents an overlap of the disciplines of [[astronomy]] and [[chemistry]]. On the Solar System scale, the study of chemical elements is usually called [[cosmochemistry]].
-Astrochemistry involves the use of [[telescope]]s to measure various aspects of bodies in space, such as their [[temperature]] and composition. Findings from the use of [[spectroscopy]] in [[chemistry]] laboratories can be employed in determining the types of [[molecule]]s in astronomical bodies (e.g. a [[star]] or an [[interstellar cloud]]). The various characteristics of molecules reveal themselves in their spectra, yielding a unique spectral representation corresponding for a molecule. However, there are limitations on measurements due to electromagnetic interference and, more problematic, the chemical properties of some molecules.  For example, the most common molecule (H<sub>2</sub>, [[hydrogen]] gas), does not have a [[dipole]] moment, so it is not detected by radio telescopes. Much easier to detect with radio waves, due to its strong electric dipole moment, is CO (carbon monoxide). Over a hundred molecules (including radicals and ions) have been reported so far, including a wide variety of organic compounds, such as alcohols, acids, aldehydes, and ketones.  There have been claims regarding interstellar [[glycine]], the simplest [[amino acid]], but with considerable accompanying controversy.  Research is progressing on the way interstellar and circumstellar molecules form and interact, and this research could have a profound impact on our understanding of the [[origin of life]] on earth.
+== Detection of chemicals ==
-The sparseness of interstellar and interplanetary space results in some unusual chemistry, since symmetry-forbidden reactions cannot occur except on the longest of timescales.  For this reason, molecules and molecular ions which are unstable on Earth can be highly abundant in space, for example the [[Protonated molecular hydrogen|H<sub>3</sub><sup>+</sup>]] ion.
+=== Methods of detection ===
-Astrochemistry overlaps strongly with astrophysics and [[nuclear physics]] in characterizing the [[nuclear reaction]]s which occur in stars, the consequences for stellar evolution, as well as stellar 'generations'. Indeed, the nuclear reactions in stars produce every naturally-occurring [[chemical element]]. As the stellar 'generations' advance, the mass of the newly-formed elements increases. A first-generation star uses elemental [[hydrogen]] (H) as a fuel source and produces [[helium]] (He). Hydrogen is the most abundant element, and it is the basic building block for all other elements as its nucleus has only one [[proton]]. Gravitational pull toward the center of a star creates massive amounts of heat and pressure, which cause [[nuclear fusion]].  Through this process of merging nuclear mass, heavier elements are formed. [[Lithium]], [[carbon]], [[nitrogen]] and [[oxygen]] are examples of elements that form in stellar fusion. After many stellar generations, very heavy elements are formed (e.g. [[iron]] and [[lead]]).
+Astrochemistry involves the use of [[telescope]]s to measure various aspects of bodies in space, such as their [[temperature]] and composition. Findings from the use of [[spectroscopy]] in [[chemistry]] laboratories can be employed in determining the types of [[molecule]]s in astronomical bodies (e.g. a [[star]] or an [[interstellar cloud]]). The various characteristics of molecules reveal themselves in their spectra, yielding a unique spectral representation corresponding to each type of molecule.
+=== Limits of detection ===
+However, there are limitations on measurements due to electromagnetic interference and, more problematic, the chemical properties of some molecules.  For example, the most common molecule (H<sub>2</sub>, [[hydrogen]] gas), does not have a [[dipole]] moment, so it is not detected by radio telescopes. Much easier to detect with radio waves, due to its strong electric dipole moment, is CO (carbon monoxide).
+=== Molecules detected ===
+Over a hundred molecules (including radicals and ions) have been reported so far, including a wide variety of organic compounds, such as alcohols, acids, aldehydes, and ketones.  There have been claims regarding interstellar [[glycine]], the simplest [[amino acid]], but with considerable accompanying controversy. Research is progressing on the way interstellar and circumstellar molecules form and interact, and this research could have a profound impact on our understanding of the [[origin of life]] on Earth.
+The sparseness of interstellar and interplanetary space results in some unusual chemistry, because symmetry-forbidden reactions cannot occur except on the longest of timescales. For this reason, molecules and molecular ions that are unstable on Earth can be highly abundant in space, for example the [[Protonated molecular hydrogen|H<sub>3</sub><sup>+</sup>]] ion.
+Astrochemistry overlaps strongly with astrophysics and [[nuclear physics]] in characterizing the [[nuclear reaction]]s that occur in stars, the consequences for stellar evolution, as well as stellar 'generations'. Indeed, the nuclear reactions in stars produce every naturally-occurring [[chemical element]]. As the stellar 'generations' advance, the mass of the newly-formed elements increases. A first-generation star uses elemental [[hydrogen]] (H) as a fuel source and produces [[helium]] (He). Hydrogen is the most abundant element, and it is the basic building block for all other elements as its nucleus has only one [[proton]]. Gravitational pull toward the center of a star creates massive amounts of heat and pressure, which cause [[nuclear fusion]].  Through this process of merging nuclear mass, heavier elements are formed. [[Lithium]], [[carbon]], [[nitrogen]] and [[oxygen]] are examples of elements that form in stellar fusion. After many stellar generations, very heavy elements are formed (e.g. [[iron]] and [[lead]]).
 == See also ==