EXPLORING THE UNIVERSE: SPACE-BASED ASTRONOMY AND ASTROPHYSICS ...

• cours magistral

EXPLORING THE UNIVERSE: SPACE-BASED ASTRONOMY AND ASTROPHYSICS Nancy Grace Roman Astronomy before 19581 For millennia until the Second World War, astronomical observations were limited to visible light, the type of electromagnetic radiation sensed by the human eye.2 When people look at the sky with the naked eye, they see only stars and patches of dark against dense star backgrounds, as in the southern Milky Way. With a telescope, one can see nebulae, or clouds of gas, shining either by fluorescence or by reflected light.

• astronomical observations
• neutral hydrogen
• clear division of interest between the astronomers
• astronomy program
• j. j. oberly
• interest of members of an astronomical community
• observations
• sky
• stars
• space