“The first step is that we need to revisit the validity of Newton’s universal law of gravitation. Starting in the 1980s, Mordehai Milgrom at the Weizmann Institute in Israel showed that a small generalisation of Newton’s laws can yield the observed dynamics of matter in galaxies and in galaxy clusters without dark matter. This approach is broadly known as MOND (MOdified Newtonian Dynamics). Milgrom’s correction allows gravitational attraction to fall off with distance more slowly than expected (rather than falling off with the square of distance as per Newton) when the local gravitational acceleration falls below an extremely low threshold. This threshold could be linked to other cosmological properties such as the ‘dark energy’ that accounts for the accelerating expansion of the Universe. These links suggest a deeper fundamental theory of space, time and matter, which has not yet been formulated.”

—  Pavel Kroupa

[Pavel Kroupa, Has dogma derailed the scientific search for dark matter?, aeon.co, November 2016, https://aeon.co/ideas/has-dogma-derailed-the-scientific-search-for-dark-matter]

Adopted from Wikiquote. Last update June 3, 2021. History

Help us to complete the source, original and additional information

Do you have more details about the quote "The first step is that we need to revisit the validity of Newton’s universal law of gravitation. Starting in the 1980s,…" by Pavel Kroupa?
Pavel Kroupa photo
Pavel Kroupa 8
Australian astrophysicist 1963

Related quotes

Vera Rubin photo

“There is one alternative to dark matter, and that is the assumption that Newton's laws don't hold over distances as great as galaxies. But we know that Newton's laws hold over a very large domain. And virtually one hundred percent of the physics and astronomy community believes that there is matter in the universe that does not radiate.”

Vera Rubin (1928–2016) American astronomer

As quoted in [Astronomer Vera Rubin—The Doyenne of Dark Matter, Discover Magazine, http://discovermagazine.com/2002/jun/breakdialogue] (1 June 2002)

Anu Garg photo

“Scientifically speaking, an overweight person is more attractive than a skinny one. Newton's Law of Gravitation.”

Anu Garg (1967) Indian author

Facebook post https://www.facebook.com/wordsmithorg/posts/10157765608546840

“The concordance model of cosmology, ΛCDM, provides a satisfactory description of the evolution of the universe and the growth of large scale structure. Despite considerable effort, this model does not at present provide a satisfactory description of small scale structure and the dynamics of bound objects like individual galaxies. In contrast, MOND provides a unique and predictively successful description of galaxy dynamics, but is mute on the subject of cosmology. … it is far from obvious that the mass spectrum of galaxy clusters or the power spectrum of galaxies can be explained in MOND, two things that ΛCDM does well. Critical outstanding issues are the development of an acceptable relativistic parent theory for MOND, and the reality of the non-baryonic dark matter of ΛCDM. Do suitable dark matter particles exist, or are they a modern aether?”

Stacy McGaugh (1964) American astronomer

A Tale of Two Paradigms: the Mutual Incommensurability of LCDM and MOND, Stacy McGaugh, 29 Apr 2014, updated 17 May 2014 http://arxiv.org/abs/1404.7525,

“The current cosmological paradigm, the cold dark matter model with a cosmological constant, requires that the mass-energy of the Universe be dominated by invisible components: dark matter and dark energy. An alternative to these dark components is that the law of gravity be modified on the relevant scales. A test of these ideas is provided by the baryonic Tully-Fisher relation (BTFR), an empirical relation between the observed mass of a galaxy and its rotation velocity. Here, I report a test using gas rich galaxies for which both axes of the BTFR can be measured independently of the theories being tested and without the systematic uncertainty in stellar mass that affects the same test with star dominated spirals. The data fall precisely where predicted a priori by the modified Newtonian dynamics.”

Stacy McGaugh Novel Test of Modified Newtonian Dynamics with Gas Rich Galaxies

[21 March 2011, Novel test of modified Newtonian dynamics with gas rich galaxies, Physical Review Letters, 106, 12, 121303, 10.1103/PhysRevLett.106.121303]

“Galaxies are observed to be simple systems following laws that result from scale-invariant dynamics which do not emanate from the haphazard merging history of halos of exotic dark matter.”

Pavel Kroupa (1963) Australian astrophysicist

Do astronomical data contradict the existence of dynamically relevant cold or dark matter? (seminar talk at Columbia U. Astronomy Department), Pavel Kroupa, 16 Oct. 2014 http://www.astro.columbia.edu/event?eid=185,

Arthur Stanley Eddington photo

“Some mechanism seems to be needed, whereby either gravitation creates matter, or all the matter in the universe conspires to define a law of gravitation.”

Arthur Stanley Eddington (1882–1944) British astrophysicist

Space, Time and Gravitation (1920)
Context: We can see that, the constant in the law of gravitation being fixed, there may be some upper limit to the amount of matter possible; as more and more matter is added in the distant parts, space curves round and ultimately closes; the process of adding more matter must stop, because there is no more space, and we can only return to the region already dealt with. But there seems nothing to prevent a defect of matter, leaving space unclosed. Some mechanism seems to be needed, whereby either gravitation creates matter, or all the matter in the universe conspires to define a law of gravitation.<!--p.163

John D. Barrow photo

“What Hubble discovered was the expansion of the universe…. We are not expanding. Nor is Brooklyn. Nor is earth. Nor is the solar system. Nor, in fact, is the Milky Way galaxy. Nor even those aggregates of thousands of galaxies that we call "galaxy clusters." These collections of matter are bound together by chemical and gravitational forces between their constituents—forces that are stronger than the force of expansion.”

John D. Barrow (1952–2020) British scientist

The Origin of the Universe (1997)

“A long standing prediction (Milgrom 1983) of MOND is that rotating galaxy curves will fall on a single mass-velocity relation with slope 4: Mb \propto Vf4. This prediction is realized in multiple independent data sets. Gas rich galaxies fall where predicted by MOND with no free parameters. There are not many predictions in extragalactic astronomy that fare so well a quarter century after their publication. … a physical understanding for why galaxy formation in the context of ΛCDM should pick out the particular phenomenology predicted a priori by MOND remains wanting.”

Stacy McGaugh (1964) American astronomer

[Stacy McGaugh, 2011, The Baryonic Tully-Fisher Relation of Gas-Rich Galaxies as a Test of ΛCDM and MOND, p. 16, ApJ, http://arxiv.org/abs/1107.2934]

Jacob Bekenstein photo

“Within the DM paradigm the Tully-Fisher law must arise from galaxy formation since it connects luminosity of baryonic matter with a dynamical property, rotation, which is seen as dominated by the DM halo. But it has not been easy to derive Tully-Fisher from any natural connection between the two components. And as R. H. Sanders has pointed out, the messiness of galaxy formation is hardly the natural backdrop for such a sharp correlation between galaxy properties. The sharpness needs a dynamical reason as opposed to an evolutionary one.”

Jacob Bekenstein (1947–2015) Mexican-Israeli physicist

[Alternatives to dark matter: Modified gravity as an alternative to dark matter, arXiv preprint arXiv:1001.3876, 21 January 2010, https://arxiv.org/abs/1001.3876]

N. S. Rajaram photo

“Fabricating astronomical data going back thousands of years calls for knowledge of Newton’s Law of Gravitation and the ability to solve differential equations.”

N. S. Rajaram (1943–2019) Indian mathematician

N.S. Rajaram: The Politics of History, p.47.

Related topics