# Which of the following is a consequence of hubble’s law

## What is the Hubble’s Law Why is it significant?

Because the exact value of the Hubble constant, H, is so important in extragalactic astronomy and cosmology – it leads to an estimate of the age of the universe, helps test theories of Dark Matter and Dark Energy, and much more – a great deal of effort has gone into working it out. …

## Why is Hubble’s law so important quizlet?

Why are Hubble’s Law and the Hubble constant important? More distant galaxies move away from us faster with a very simple formula (velocity = Ho x distance). … Applies to all distant galaxies for which we can measure redshift, most useful technique for determining distances to galaxies that are very far away.

## What are two properties of a Cepheid variable?

A Cepheid variable (/ˈsɛfiːɪd, ˈsiːfiːɪd/) is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude.

## What is the most accurate way to determine the distance to a nearby galaxy?

Astronomers can use what are called surface brightness fluctuations (SBF, for short), along with the color of a galaxy, to calculate how far away it is from earth. Most galaxies measured in this way are millions of light years away.

## What can we learn from Hubble’s law?

Hubble’s law, which says simply that a galaxy’s velocity (or as is sometimes plotted, its redshift) is directly proportional to its distance, also tells us something important about the state of the universe.

## What is Hubble’s law formula?

Hubble’s Law – One of the most important formulas of the 20th century. … Formula: v = Ho d where: v = velocity of a galaxy, in km/s. Ho = Hubble Constant, measured in km/s/Mpc.

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## How is Hubble’s constant calculated?

The Hubble Constant can be stated as a simple mathematical expression, Ho = v/d, where v is the galaxy’s radial outward velocity (in other words, motion along our line-of-sight), d is the galaxy’s distance from earth, and Ho is the current value of the Hubble Constant.

## Why do we call dark matter dark quizlet?

Why do we call dark matter “dark”? It emits no radiation that we have been able to detect. … The flat rotation curves of spiral galaxies tell us that they contain a lot of dark matter.

## Which types of galaxies have a clearly defined disk component?

Lenticular galaxies are like a cross between spirals and ellipticals and are also disc-shaped. Ellipticals are like big eggs or spheres, and irregular galaxies are unclear blobs.

## What is the difference between Type 1 and Type 2 Cepheids?

There are actually two classes of Cepheid: Type I Cepheids (δ Cepheus is a classical Cepheid) are population I stars with high metallicities, and pulsation periods generally less than 10 days. Type II Cepheids (W Virginis stars), are low-metallicity, population II stars with pulsation periods between 10 and 100 days.

## Why do Cepheids pulsate?

Pulsating variable stars are intrinsic variables as their variation in brightness is due to a physical change within the star. In the case of pulsating variables this is due to the periodic expansion and contraction of the surface layers of the stars.

## Is the sun a Cepheid variable?

Artist’s impression of the eclipsing binary system, including a pulsating star called a Cepheid variable. Our own sun is a variable star; its energy output varies by approximately 0.1 percent, or one-thousandth of its magnitude, over an 11-year solar cycle. …

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## How are star distances calculated?

Astronomers estimate the distance of nearby objects in space by using a method called stellar parallax, or trigonometric parallax. Simply put, they measure a star’s apparent movement against the background of more distant stars as Earth revolves around the sun.

## What is the difference between brightness and luminosity?

When I say apparent brightness, I mean how bright the star appears to a detector here on Earth. The luminosity of a star, on the other hand, is the amount of light it emits from its surface. The difference between luminosity and apparent brightness depends on distance.