Our instruments were too primitive to detect them.
We thought the earth’s ionosphere was blocking them.
Until Karl Guthe Jansky, investigating the source
of static that interfered with shortwave receptions,
discovered a signal repeating every sidereal day
that wasn’t coming from the sun.
It came from the mysterious heart of our galaxy
in the constellation of Sagittarius.
Sagittarius A*
At the center of the Milky Way,
hidden by clouds of cosmic dust,
stars and ions orbit a massive black hole.
We cannot see the thing itself,
heavy as four million solar masses,
only emissions from things that orbit it.
Overhearing
To conduct radio astronomy,
unlike radar or normal radio,
we don’t send the signals.
The universe is full of things,
wacky and violent,
sending signals on their own.
It’s just an accident
of physics. The universe
isn’t trying to talk to us.
Radio astronomy is consistent with the adage
that you can learn a lot if you only learn to listen.
Karl Guthe Jansky’s and later discoveries in radio astronomy
became possible only as our technology improved.
Radio astronomy is consistent with the adage that you can learn a lot if you only learn to listen. Karl Guthe Jansky’s and later discoveries in radio astronomy became possible only as our technology improved.
See also in The book of science:
Readings in wikipedia: