He is called 'unemployed' and 'seeking other opportunities',
since there are no aliens available to study.
A person who studies the planets and stars is an astrologist.
Someone who studies the planet Mars is called an areologist.
A person who studies flying saucers is called a Ufologist.
Astronomy, the person who studies them is an Astronomer
I agree with the above comments. But if you want to get really fancy, you could go with Selenographer (a person who charts the surface of the Moon) or Selenologer (a person who studies the Moon).
The Person Who studies about mamals , he is called mamalogist....
skeptic
An alienologist is a person who studies aliens, the possible existence of alien or non-terrestrial life.
A person who studies volcanoes is called a volcanologist.
A person who studies the grass and soil, etc. is called a Agrostologist
A person who studies geology is a geologist.
A person who studies bees is called an apiologist.
a person that studies gems is called a gemologist.
A person who studies audiology would be called an audiologist.
A person who studies water and its properties is called a Hydrogeologist.
A person that studies animals is called a Zoologist.
A person who studies birds is called an ornithologist.