Redefining Reality - The Intellectual Implications of Modern Science

Perhaps the best evidence for extraterrestrial life is to be found on
other planets around other suns. The problem is that for a long time,
we had never seen such planets. Planets are small in astronomical
terms and give off no light.
One approach to detecting other planets is gravitational.
Strictly speaking, the Earth does not revolve around the Sun.
Instead, the Sun and the Earth both revolve around a common
point, the center of mass of the two-bodied system. The Sun is
so much heavier than the Earth that the center of mass of the
two is actually located within the Sun itself.
As a result, when the Earth moves around this point, it moves
around the Sun. But when the Sun moves around it, it is
revolving around a point inside of itself, not at its center. The
result is a wobble, much like someone keeping a hula hoop
going around his or her waist. The heavier the planet, the larger
the wobble in the Sun.
We can look for these solar wobbles optically; that is, if the
planet is large enough and the star close enough, we might be
able to see the movement over time. But a better way to spot
the movement is by observing Doppler shifts. We can check
exoplanet was discovered.
Pulsars are stars that emit a strong beam of light. As the star
a police car. The astronomers Aleksander Wolszczan and
Dale Frail noticed that the behavior of a pulsar star they were
observing was a bit askew. Their calculations showed that this
had to be the result of two planets orbiting the pulsar; thus, the
age of exoplanets was launched.
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