From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.6 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 121.8 nm.
What can we conclude? A) The star is moving toward us.
B) The star is moving away from us.
C) The star is getting hotter.
D) The star is getting colder.
E) The star actually is a planet.
Question 2
In special relativity, we learned that people in different reference frames will measure time differently. According to general relativity, why does this happen?
A) People in different reference frames experience different realities.
B) It is an illusion, and time really is the same for everyone.
C) They have different worldlines.
D) They are experiencing the same spacetime reality, but from different perspectives.
Brain Cells of a laboratory mouse
Spectral and photochemical properties of photoactivatable fluorescent proteins.
An Underwriters Laboratory mark.
Types of Laboratory Tests
Some Ford metal line connections use springlocks and O-rings.
Beau’s line