## Hubble's law |

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The **Hubble–Lemaître Law**, also known as **Hubble's Law**,^{[1]} is the observation in

- Objects observed in
deep space —extragalactic space, 10 megaparsecs (Mpc) or more—are found to have aredshift , interpreted as a relative velocity away fromEarth ; - This
Doppler shift -measured velocity of variousgalaxies receding from the Earth is approximatelyproportional to their distance from the Earth for galaxies up to a few hundred megaparsecs away.^{[2]}^{[3]}

Hubble–Lemaître is considered the first observational basis for the ^{[4]}^{[5]}The motion of astronomical objects due solely to this expansion is known as the **Hubble flow**.^{[6]}

Although widely attributed to ^{[7]}^{[8]}^{[9]} the notion of the universe expanding at a calculable rate was first derived from the ^{[10]} Then **Hubble constant**.^{[4]}^{[11]}^{[12]}^{[13]} Though the Hubble constant is roughly constant in the velocity-distance space at any given moment in time, the **Hubble parameter** , which the Hubble constant is the current value of, varies with time, so the term 'constant' is sometimes thought of as somewhat of a misnomer.^{[14]} Moreover, two years later Edwin Hubble confirmed the existence of cosmic expansion, and determined a more accurate value for the constant that now bears his name.^{[15]}Hubble inferred the recession velocity of the objects from their ^{[16]}^{[17]}^{[18]}^{[19]}

The law is often expressed by the equation *v* = *H*_{0}*D*, with *H*_{0} the constant of proportionality—Hubble constant—between the "proper distance" *D* to a galaxy, which can change over time, unlike the *v*, i.e. the * uses of the proper distance* for some discussion of the subtleties of this definition of 'velocity'.) Also, the SI unit of

- discovery
- interpretation
- determining the hubble constant
- derivation of the hubble parameter
- units derived from the hubble constant
- measured values of the hubble constant
- see also
- notes
- references
- further reading
- external links

A decade before Hubble made his observations, a number of

In 1912, ^{[21]}^{[22]}

In 1922, ^{[23]} The parameter used by Friedmann is known today as the

In 1927, two years before Hubble published his own article, the Belgian priest and astronomer ^{[24]} It is now known that the alterations in the translated paper were carried out by Lemaitre himself.^{[12]}^{[25]}

Before the advent of

Edwin Hubble did most of his professional astronomical observing work at *spiral nebulae*” enabled him to calculate the distances to these objects. Surprisingly, these objects were discovered to be at distances which placed them well outside the

The parameters that appear in Hubble's law, velocities and distances, are not directly measured. In reality we determine, say, a supernova brightness, which provides information about its distance, and the redshift *z* = ∆*λ*/*λ* of its spectrum of radiation. Hubble correlated brightness and parameter *z*.

Combining his measurements of galaxy distances with

At the time of discovery and development of Hubble's law, it was acceptable to explain redshift phenomenon as a *z* with velocity. Today, in the context of general relativity, velocity between distant objects depends on the choice of coordinates used, and therefore, the redshift can be equally described as a Doppler shift or a cosmological shift (or gravitational) due to the expanding space, or some combination of the two.^{[29]}

Hubble's law can be easily depicted in a "Hubble Diagram" in which the velocity (assumed approximately proportional to the redshift) of an object is plotted with respect to its distance from the observer.^{[30]} A straight line of positive slope on this diagram is the visual depiction of Hubble's law.

After Hubble's discovery was published, ^{[31]} After Hubble's discovery that the universe was, in fact, expanding, Einstein called his faulty assumption that the universe is static his "biggest mistake".^{[31]} On its own, general relativity could predict the expansion of the universe, which (through

In 1931, Einstein made a trip to ^{[32]}

The cosmological constant has regained attention in recent decades as a hypothesis for ^{[33]}

Other Languages

Afrikaans: Wet van Hubble

العربية: قانون هابل

asturianu: Llei de Hubble

azərbaycanca: Habbl qanunu

বাংলা: হাবলের সূত্র

беларуская: Закон Хабла

български: Закон на Хъбъл

bosanski: Hubbleov zakon

català: Constant de Hubble

čeština: Hubbleova konstanta

dansk: Hubbles lov

Deutsch: Hubble-Konstante

eesti: Hubble'i seadus

Ελληνικά: Νόμος του Χαμπλ

español: Ley de Hubble

Esperanto: Leĝo de Hubble

euskara: Hubbleren legea

فارسی: قانون هابل

français: Loi de Hubble-Lemaître

Gaeilge: Tairiseach Hubble

galego: Constante de Hubble

한국어: 허블-르메트레 법칙

հայերեն: Հաբլի օրենք

hrvatski: Hubbleov zakon

Ido: Konstanto di Hubble

Bahasa Indonesia: Hukum Hubble

íslenska: Lögmál Hubbles

italiano: Legge di Hubble

עברית: חוק האבל

ಕನ್ನಡ: ಹಬಲ್ಲನ ನಿಯಮ

ქართული: ჰაბლის კანონი

қазақша: Хаббл заңы

latviešu: Habla likums

Lëtzebuergesch: Hubble-Konstant

lietuvių: Hablo dėsnis

magyar: Hubble–Lemaître-törvény

മലയാളം: ഹബ്ബിൾ നിയമം

Bahasa Melayu: Hukum Hubble

Nederlands: Wet van Hubble-Lemaître

日本語: ハッブル=ルメートルの法則

norsk: Hubbles lov

occitan: Lei de Hubble

پنجابی: ہبل دا قنون

polski: Prawo Hubble’a

português: Lei de Hubble

română: Legea lui Hubble

русский: Закон Хаббла

Scots: Hubble's law

sicilianu: Liggi di Hubble

Simple English: Hubble's law

slovenčina: Hubblov zákon

slovenščina: Hubblov zakon

српски / srpski: Hablov zakon

srpskohrvatski / српскохрватски: Hablov zakon

suomi: Hubblen laki

svenska: Hubbles lag

தமிழ்: ஹபிள் விதி

татарча/tatarça: Habbl qanunı

ไทย: กฎของฮับเบิล

Türkçe: Hubble kanunu

українська: Закон Габбла

اردو: قانون ہبل

Tiếng Việt: Định luật Hubble

West-Vlams: Wet van Hubble

吴语: 哈勃定律

粵語: 哈勃定律

中文: 哈勃–勒梅特定律