Discuss the possibility that star velocities at the edges of galaxies being greater than expected is due to unknown propertiesof gravity rather than to the existence of dark matter. Would this mean, for example, that gravity is greater or smaller thanexpected at large distances? Are there other tests that could be made of gravity at large distances, such as observing themotions of neighboring galaxies?

Discuss the possibility that star velocities at the edges of galaxies being greater than expected is due to unknown propertiesof gravity rather than to the existence of dark matter. Would this mean, for example, that gravity is greater or smaller thanexpected at large distances? Are there other tests that could be made of gravity at large distances, such as observing themotions of neighboring galaxies?

Related questions

Q: Pretend that galaxies are spaced evenly, 4.0 Mpc apart, and the average mass of a galaxy is 1.0 x…

Q: What mechanism can simultaneously solve both the flatness and horizon problems in cosmology?

A: What mechanism can simultaneously solve both the flatness and horizon problems in cosmology

Q: (b) Draw the shape of the Milky Way for a spaceship with a velocity of 20%, 50%, and 90% of the…

Q: Consider a universe in which the Hubble constant has been measured to have the value H0 = 50…

A: Hubble's law gives the idea that the universe is continuously expanding, and that galaxies are…

Q: (d) Scientists believe the reasons for the difference to be dark matter: Determine the rotational…

A: line indications: Vobserved - Blue Vcalculated - Red VDM - Green

Q: A 2 GHz radio signal is detected from a galaxy as 0.86GHz. Estimate the relative velocity.

A: Like all waves light waves also get Doppler shifted. In the case of light waves, the Doppler shift…

Q: Give the peak wavelengths, λpeak, for each of the following cases. State which portion of the…

A: Given,

Q: The presence of neutral hydrogen in galaxies will be observed with the SKA through the redshifted…

A: Given Data: Rest frame frequency=1420MHz Redshift z=0.5 To Find: The frequency would we need to look…

Q: Observations of quasars have shown us that many are extremely _________, emitting more energy than…

A: Required : Fill in the gaps.

Q: Compute a numerical value (in units of protons/m3 ) for the critical density of our Universe. How…

A: The critical density for the Universe is given by, ρ = 3H28πG where H is the Hubble constant and G…

Q: Use the Friedmann equations to show that the deceleration parameter go and the density parameter N…

A: According to Dark energy and the cosmological constant, the acceleration of the scale factor is…

Q: 3C 273 was the first quasar identified (1963). When we look at its chemical spectrum, we see that…

A: Given:- λobs = 759 nm.λ0 = 656 nm

Q: According to the version of the Big Bang Theory without a Cosmological Constant (and without Dark…

A: Hubble's Law states that as the universe is expanding in all directions, the receding velocity of an…

Q: Explain why it only appears that we are at the center of expansion of the universe and why an…

A: Universe is expanding from everywhere and it has no center of expansion. Materials expand from a…

Q: What is the redshift z of a galaxy 186 Mpc away from us? Note: Assume a value of the Hubble…

A: Hubble's law, also known as Hubble- Lemaitre law states that the velocity of the galaxy, also called…

Q: What is the redshift z of a galaxy 172 Mpc away from us? Note: Assume a value of the Hubble…

Q: Please answer within 90 minutes.

A: c) Calculate the Critical Density of the Universe TodayUsing H0=68 km/s/Mpc: H0=2.20×10−18 s−1…

Q: An object is measured to be at a distance of 20 Megaparsecs away from Earth. Using a currently…

A: According to the Hubble's law, galaxies are moving away from Earth at speeds proportional to their…

Q: By what factor would the critical density of the universe today change if the Hubble constant today…

A: Understanding the critical density of the universe is pivotal in unraveling its composition. The…

Q: What is the Eddington luminosity of a quasar with a mass of 1 billion Msun ?

A: Eddington luminosity or Eddington limit is the maximum luminosity that can be achieved by a star in…

Question

Discuss the possibility that star velocities at the edges of galaxies being greater than expected is due to unknown properties
of gravity rather than to the existence of dark matter. Would this mean, for example, that gravity is greater or smaller than
expected at large distances? Are there other tests that could be made of gravity at large distances, such as observing the
motions of neighboring galaxies?

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

This is a popular solution!

SEE SOLUTION Check out a sample Q&A here

Step 1

VIEW

Step 2

VIEW

Trending now

This is a popular solution!

Step by step

Solved in 2 steps

SEE SOLUTION Check out a sample Q&A here

Similar questions

You find a small satellite galaxy orbiting 66 kpc from the center of a larger galaxy at a speed of 210 km/s. What is the total mass of the galaxy-satellite galaxy system? (Give your answer in terms of MSun.)
Suppose an alien race on a distant planet tries to send a message to us, with a laser (light). However, we were unaware that there is a stellar-mass black hole almost directly between us and them. How would this complicate our attempts to locate their position in the Galaxy? O Gravitational lensing would make the signal appear to be coming from a different location O The information carried by the laser (light) would be altered O It would not matter The black hole absorbs all of the light
With the aid of a diagram, explain the physical origin of cosmological redshift in an expanding universe, and how this differs from the Doppler shift due to relative motion. Observations of distantgalaxies indicate that their recession velocities, v, and their distances, d, follow a Hubble Law:v = H0d, where H0 is a constant. Using the analogy of an expanding grid or ruler, demonstratethat Hubble’s Law indicates that the Universe is undergoing uniform expansion.
Suppose you have obtained spectra of several galaxies and have measuerd the observed wavelength of the H-Alpha line (rest wavelength = 656.3 nm) to be Galaxy 1: 658.1 nm. Galaxy 2: 667.1 nm. Galaxy 3: 677.6 nm. Assuming a Hubble Constant of 72.5 km/s/Mpc, calculate the distance to each of these galaxies (answer in Mpc)
A survey that uses Type la supernovae as standard candles to measure the distances to galaxies, combined with spectroscopic analysis of those galaxies Select one: to obtain their redshifts and recession velocities, yields the data shown in the The Universe is undergoing а. table. Use the data to sketch a diagram of velocity versus distance. Choose the accelerated expansion statement given below that can be O b. The Universe is contracting. inferred from the data. Velocities and distances to Ос. The data does not provide sufficient galaxies information to determine the rate of Distance (Mpc) expansion of the Universe. Velocity (km/s) 10 730 d. The expansion rate of the Universe is 250 16250 constant 500 30000 e. The expansion of the Universe is 800 40000 decelerating. 1000 45000
The critical density of a universe is around 5×10-27 kg/m³. Estimate the Hubble constant for this universe.
Please answer within 90 minutes.
Briefly explain what is meant by “particle horizon” and “event horizon” in cosmology. Calculate the physical particle horizon, RH(t), at time t. Assume a flat FRW universe whichis dominated by a fluid that gives rise to scale factor evolution where n is a constant with 0 < n < 1, and a(t0) = a0.