Astronomers have measured light from stars in galaxies that
are billions of years old. Which of the following must be true
about energy for this to be possible?
When stars emit energy in the form of light it travels to Earth faster
than other places in the Universe.
Energy in the form of light can only travel toward objects.
When energy in the form of light is redshifted it is no longer
measurable.
Energy in the form of light travels across space and cannot be
destroyed