What are some problems with MOND?

MOND also encounters difficulties explaining structure formation, with density perturbations in MOND growing too late to form the galaxies and clusters observed today. Several other studies have noted observational difficulties with MOND.

Why is MOND still considered valid?

MOND makes unique predictions about the relation between the mass distribution and kinematics. These predictions are confirmed with surprising accuracy in the observed rotation curves of observed galaxies, a phenomenon which is exceptionally well established observationally (Sanders & McGaugh 2002).

Who modified Newton’s laws under extreme circumstances?

Only in extreme circumstances do Newton’s laws break down, and this fact was not realized until the twentieth century, when Albert Einstein’s theories of relativity once again revolutionized our view of the universe (see Chapter 22).

Can MOND explain the bullet cluster?

A famous example is the Bullet Cluster, which consists of two such colliding clusters. Observations suggest that dark matter follows the stars in these events, which have a lower total mass than the gas cloud. MOND cannot explain why that is.

Does Mond explain gravitational lensing?

Modified Newtonian dynamics (MOND) is an alternative theory of gravity that aims to explain large-scale dynamics without recourse to any form of dark matter. However, the theory is incomplete, lacking a relativistic counterpart, and so makes no definite predictions about gravitational lensing.

What does MOND mean?

MOND

Acronym	Definition
MOND	Modified Newtonian Dynamics (missing dark matter theory)
MOND	Ministry of National Defence (various nations)

Is MOND dead?

MOND is a controversial alternative to general relativity, the prevailing Einstein-inspired understanding of the phenomenon of gravity, that requires dark matter to exist, but this has never been proved. MOND does not require dark matter. The now debunked study claimed MOND was dead.

Does MOND explain gravitational lensing?

Can Mond explain gravitational lensing?

Is Mond relativistic?

Here I briefly review MOND as well as its implementation as a nonrelativistic modified gravity theory, AQUAL. Gravitational lensing and cosmology call for a relativistic gravity theory different from general relativity if dark matter is to be avoided.

Are there galaxies with no dark matter?

DF2 isn’t the only galaxy devoid of dark matter. Shany Danieli of the Institute for Advanced Study in Princeton, New Jersey, used Hubble in 2020 to obtain an accurate distance to another ghostly galaxy, called NGC 1052-DF4 (or simply DF4), which apparently lacks dark matter, too.

Does dark matter cause gravitational lensing?

Dark matter is an invisible form of matter that makes up most of the universe’s mass and creates its underlying structure. Dark matter’s gravity drives normal matter (gas and dust) to collect and build up into stars and galaxies. This phenomenon is called gravitational lensing.