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Book by David Michalets

Distant Spectral Shifts

6 Star vs Galaxy

This is section 6 of 18.

The web page series for Distant Spectral Shifts is based on my book Cosmology Crisis Cleared.

An astronomer in France captured the spectra of M31 galaxy and 3 stars on one web page. The page is  referenced here.  [Reference:

The Radial Velocity Measure of nearby galaxies

To view the page, click on this link.

To view only the image described below, click on this link:  ]

The spectrum of M31 galaxy is at the left in the image, while  3 stars of different types are at the right.

The M31 spectrum has the distinctive, relatively flat intensities with erratic fluctuations spanning from ultraviolet at the left to infrared at the right.

Any big dips are absorption lines from atoms in the line of sight to the galaxy.

There are 2 close absorption lines just below 4000A. This pair is from a calcium ion. They are slightly blue shifted indicating a velocity of -300 km/s. This is the velocity incorrectly assigned to M31.  These calcium ions have the same velocity as ions in the slow solar wind. The massive M31 is not moving at the same velocity as particles in the slow solar wind. Absorption and emission lines in a galaxy spectrum must be ignored, to avoid assigning a wrong velocity to the galaxy.

The 3 stars have different colors. All are emitting thermal radiation which has a wavelength distribution defined by the temperature of the surface which is transferring some of its thermal energy to electromagnetic radiation, in the form of thermal radiation.
Blue is the hot, type A1 star. Note its highest intensity wavelength is at the far left, at about 4000A, in ultraviolet.

Green is the temperate type G2V star which is like our Sun. Note its highest intensity wavelength is around 6000A or yellow, in visible. This star will look white as the intensity of all the visible colors are the same. The human eye will se the mix of wavelengths as white.

Red is the cool, type K5 star, Aldebaran, or a red giant. Note its highest intensity wavelength is at the right, at about 7000A, or the color red. The figure cut off above 7000A, with the infrared wavelengths.

Note that all 3 stars have some absorption lines in their spectrum. These atoms must be attached to the photosphere. If a star is moving in the line of sight to Earth, then by the Doppler effect the entire spectrum would shift to the left (shorter wavelengths) when moving toward Earth, or to the right (longer wavelengths) when moving away.

The astronomer can inspect the absorption lines, identify their elements, calculate the z value from the ratio of change to nominal wavelength, multiply z time c to get a velocity of the atoms on the photosphere. While attached, they have a common velocity.

A galaxy has no external light-emitting surface likee a photosphere for atoms attaching, so all atoms in the line of sight to a galaxy are never attached and can never have a common velocity.

When looking at the spectra on the earlier page, they look similar.

The astronomer must remember the lines with a star can be measured, but the lines with a galaxy must be ignored.

Since cosmology is in a crisis by wrong velocities, clearly, for over 100 years, astronomers were never told this simple rule for galaxies.

The same rule applies to quasars. The section Quasars has the spectrum of a typical quasar. It has many emission lines, coming from different elements. A quasar has no external surface for atoms attaching. All lines with a quasar must be ignored because none share a velocity with the quasar.

Astronomers must remember the rules for measuring the velocity of a star CANNOT be used for a galaxy or quasar.

When having no outer light-emitting surface, it is impossible for a galaxy or quasar to reveal its velocity by lines from atoms in its spectrum.

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;ast update: 01/05/2022