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Tricks and tips for everyone

# How do you find the rotation of a galaxy curve?

## How do you find the rotation of a galaxy curve?

The rotation curves of galaxies can be measured using neutral hydrogen observations with radio telescopes. By equating the gravitational force to the centrifugal force we can estimate the mass inside a certain radius.

How do you calculate the rotational speed of a galaxy?

Let’s find out. -Imagine a (spherical) galaxy that has a constant mass density ρ. -The velocity of a star on a circular orbit inside the galaxy changes as a function of radius in the following way: =Mass / Volume=M / 4/3r3  M = 4 /3r3  where ρ is constant.

How are rotation curves of spiral galaxies determined?

A simple “rotation curve” is an approximation as a function of radius to the full velocity field of a disk galaxy. As such, it can be obtained only by neglecting small-scale velocity variations, and by averaging and smoothing rotation velocities from both sides of the galactic center.

### What is the rotation curve method?

To make a rotation curve one calculates the rotational velocity of e.g. stars along the length of a galaxy by measuring their Doppler shifts, and then plots this quantity versus their respective distance away from the center.

What does the rotation curve of our galaxy tell us?

The rotation curve tells you the amount of mass inside a given distance from the center. You find how the mass is distributed in the Galaxy by looking at how the amount of enclosed mass changes with the size of the orbits.

What is the rotation curve of a galaxy quizlet?

the rotation curve of galaxies is. the orbital speed of stars and gas around a galaxy at different radii from the center. Because of the presense of dark matter, the rotation curve of galaxies. flattens at large radius.

#### Who measured rotation curves of spiral galaxies?

In the late 1960s and early 1970s, Vera Rubin, an astronomer at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, worked with a new sensitive spectrograph that could measure the velocity curve of edge-on spiral galaxies to a greater degree of accuracy than had ever before been achieved.

How do you calculate the rotational velocity of a planet?

The planetary-rotation period can even be calculated from the velocity-distance-time equation, T = D/V, where D = distance, in this case the circumference (2πR), and V = tangential velocity. angular velocity (as in Eq. 10) or its radius and tangential velocity (as in Eq.

How do you calculate the mass of the Milky Way galaxy?

The elliptical galaxy’s mass = k × (velocity dispersion)2 × (the distance the stars are from the galaxy center)/G, where k is a factor that depends on the shape of the galaxy and the angle the galaxy is from Earth.

## What does the rotation curve of our galaxy tell us quizlet?

What does the rotation curve of our Galaxy tell us about the Galaxy’s total mass? It tells us that the galaxy is much bigger then we expected, and that the luminous part of the galaxy is only the ‘tip of the iceberg’.

Why do we believe that as much as 90% of the mass of the Milky Way is in the form of dark matter?

Why do we believe 90 percent of the mass of the Milky Way is in the form of dark matter? The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars are feeling gravitational effects from unseen matter in the halo.

How are rotation curves of spiral galaxies determined quizlet?

What is the primary way in which we determine the mass distribution of a spiral galaxy? We construct its rotation curve by measuring Doppler shifts from gas clouds at different distances from the galaxy’s center.