Alexander Friedman

Infobox Scientist
name = Alexander Friedman
box_width =


image_width = 200px
caption = Alexander Friedman
birth_date = birth date|1888|6|16
birth_place = Saint Petersburg
death_date = death date and age|1925|9|16|1888|6|16
death_place = Leningrad
residence =
citizenship =
nationality = Russia
ethnicity =
field = cosmologist
work_institutions =
alma_mater =
doctoral_advisor =
doctoral_students = George Gamow
known_for =
author_abbrev_bot =
author_abbrev_zoo =
influences =
influenced =
prizes =
religion =
footnotes =

Alexander Alexandrovich Friedman or Friedmann ( _ru. Александр Александрович Фридман) (June 16 1888, Saint Petersburg, Imperial Russia – September 16 1925, Leningrad, USSR) was a Russian and Soviet cosmologist and mathematician.

Friedman's landmark discoveries made a significant contribution to our current understanding of the universe, such as in the matter of our galaxy, the Milky Way. Against previous beliefs of the time, Friedman disproved the popular idea that a kind of 'sour milk' matter existed in space (upon which the Milky Way was named) providing evidence this was merely clusters of stars. ["Out of this world myths", Time Magazine pg 54, 14th June 2006]

Life and work

Alexander Friedman lived much of his life in Leningrad. He fought in World War I (on behalf of Imperial Russia) as a bomber and later lived through the Russian Revolution of 1917.

He discovered the expanding-universe solution to general relativity field equations in 1922, which was corroborated by Edwin Hubble's observations in 1929 (Ferguson, 1991: 67). Friedman's 1924 papers, including " _de. Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes" (On the possibility of a world with constant negative curvature of space) published by the German physics journal "Zeitschrift für Physik" (Vol. 21, pp. 326-332), demonstrated that he had command of all three Friedman models describing positive, zero and negative curvature respectively, a decade before Robertson and Walker published their analysis.

This dynamical cosmological model of general relativity would come to form the standard for the Big Bang and steady state theories. Friedman's work supports both theories equally, so it was not until the detection of the cosmic microwave background radiation that the steady state theory was abandoned in favor of the current favorite Big Bang paradigm.

The classic solution of the Einstein field equations that describes a homogeneous and isotropic universe is called the "Friedmann-Lemaître-Robertson-Walker metric", or "FLRW", after Friedman, and Robertson, Walker and Georges Lemaître who worked on the problem in 1920's and 30's independently of Friedman.

In addition to general relativity, Friedman's interests included hydrodynamics and meteorology. In June 1925 he was given the job of the director of Main Geophysical Observatory in Leningrad. In July 1925 he participated in a record-setting balloon flight, reaching the elevation of convert|7400|m|ft|abbr=on|lk=off.

Friedman died on September 16, 1925, at the age of 37, from typhoid fever that he contracted during a vacation in Crimea.

Another famous physicist, George Gamow, was a student of Friedman.

ee also

*Big Bang nucleosynthesis
*infinity
*energy
*conservation of energy
*Friedmann equations

Important works

*cite journal |last=Friedman |first=A. |authorlink= |coauthors= |year=1922 |month= |title= _de. Über die Krümmung des Raumes |journal=Zeitschrift für Physik |volume=10 |issue=1 |pages=377–386 |doi=10.1007/BF01332580 |url= |accessdate= |quote= (English translation in: Gen. Rel. Grav. 31 (1999), 1991-2000.)
*cite journal |last=Friedman |first=A. |authorlink= |coauthors= |year=1924 |month= |title= _de. Über die Möglichkeit einer Welt mit konstanter negativer Krümmung des Raumes |journal=Zeitschrift für Physik |volume=21 |issue=1 |pages=326–332 |doi=10.1007/BF01328280 |url= |accessdate= |quote= (English translation in: Gen. Rel. Grav. 31 (1999), 2001-2008.)

References

*cite book |title=Stephen Hawking: Quest For A Theory of Everything |last=Ferguson |first=Kitty |authorlink= |coauthors= |year=1991 |publisher=Bantam Books |location=New York |isbn=055329895X |pages=

External links

*MacTutor Biography|id=Friedmann
* [http://books.google.ro/books?id=hvKzeJouZ9UC&pg=PA16&lpg=PA16&dq=biography+1888+%22alexander+friedman%22&source=web&ots=aCJRV4xjM_&sig=WgGfOhp7kRScYuv8Q9Dr-59KXfo&hl=ro&sa=X&oi=book_result&resnum=1&ct=result "How Do We Know the Age of the Universe" - Mary Lynn Germadnik]