Stellarium - Observation 6-1.docx - Observation 6 Hubble’s...

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Observation 6Hubble’s LawHubble’s Law describes the relationship between the distance of a galaxy and the velocity atwhich it’s receding as the universe expands from the Big Bang. In this assignment, we’ll usedistance and velocity data, using Stellarium, to estimate the Hubble constant. Knowing theHubble constant, we can then estimate the distance of galaxies and the age of the universe.Part 1: The distances and velocities of galaxies1.Launch Stellarium.2.Activate Deep-sky objects (D), deactivate Atmosphere (A), deactivate Ground (G), deactivatestars (S). Bring up theSky and viewing optionswindow (F4). UnderSky, uncheck Milky Waybrightness,Zodiacal Light brightness, andSolar System objects. UnderDSO, checkFilter bytypeand uncheck everything underFilter by typeexceptGalaxies,Active Galaxies, andInteracting Galaxies. InDisplay Objects from Catalogs, keep the defaults checked and alsocheckPGC.Your Sky setting should now look like this:
and your DSO window like this:3.With the Page Up and Page Down keys, or with the mouse scroll wheel, set the field of view(FOV) to about 45ᵒ. You should see few objects as you look around to different parts of thesky, most—but not all—of which will be galaxies. Galaxies will appear as oval shapes.4.Left-click on a galaxy to select it. In the Information window, make sure the object is listed asType: galaxy. Also make sure it has redshift data.5.Record the information in the table in the Results Sheet.You will need to calculate the radial velocity from the red shift. To do this, multiply theredshift by the speed of light, which is approximately 2.998x108 meters per second. Forexample, the redshift of Bode’s Galaxy is -0.000140. To find the radial velocity, (-0.000140)(2.998x105 km/s) = -41.972 km/s. You would record -41.972 in the radial velocity column.

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Term
Fall
Professor
aAlchemist
Tags
Hubble Constant

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