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2
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1answer
36 views

Triple Stars v/s Ternary Stars

Ternary (or trinary) stars are not the same as triple stars. So, what is the basic ...
2
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3answers
86 views

Pulsation Modes of Cepheids

There are various modes of Cepheids like single modes: fundamental (F), first overtone (1O), and likewise. And then we have double modes: F/1O, 1O/2O etc. triple modes: 1O/2O/3O etc. ...
5
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1answer
83 views

How do scientists know there are about 300 billion stars in a galaxy and there are about 100 billion galaxies?

Just to think about this is mind boggling. But how do scientist get these numbers? What technology/system/theory do they they use?
0
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1answer
185 views

Reason for disqualifying Pluto as a Planet? [duplicate]

Pluto is no longer a member of the planets in the solar system. Why was it disqualified as a planet? What is the criteria for classifying an Astronomical Object as a Planet? Does this criteria ...