Why we don’t feel the earth moving
The Sunday Nation
Nairobi,
14 September 2014
If you think that you are the most distant
reader of this column, write to me and tell me where you’re reading
from. This is not a competition and prizes are on offer: it’s just to
satisfy my curiosity. The distance of interest is that measured from
Also, if you think
you have been reading this column for longer than everybody else, please
do tell me when you started reading. Again, no competition and no
prizes!
My curiosity was
aroused by Elly Manjale, writing from
The best way to
understand why we don’t feel the Earth’s motion is to ask how we can
tell that it is moving. The answer to that is that we have to look
“outside” the Earth.
As long as we are
inside an enclosure that is moving at constant speed, we cannot detect
its motion. This explains the effect we experience when inside a lift:
we feel it accelerate as it set off, then it seems to stop, but then we
feel the deceleration as it comes to the real halt.
During the second
phase of the lifts motion, it moves at constant speed and, for that
reason, we cannot feel it moving. However, there are some lifts that
have glass walls and you can see the outside. These lifts leave many
people nauseated because the brain receives two conflicting messages –
one of motion and the other of no motion. Perhaps architects should
avoid fitting such lifts in building; but that’s a discussion for a
different forum.
As the Earth moves,
it takes everything in and on it along – including, trees, buildings,
people, and even the air of the atmosphere. So, when you look at these
things, you cannot tell whether they are in motion or not because all of
you are moving at the same constant speed.
And as pointed out
about a decade ago, the only way you can tell the state of motion of the
Earth is by looking at other heavenly bodies – the Sun, the stars, the
planets etc.
Furthermore; as the
Earth revolves at over 100,000km/h and spins at 1,675km/h (at the
equator), it is chasing the sun which is revolving around the centre of
our Milky Way galaxy at about 900,000km/h. The galaxy itself is racing
at 360,000km/h and it is in a galactic group of galaxies which is
drifting together at over 2,000,000km/h!
If you thought the
universe is complicated, imagine how it looks viewed from God’s vantage
point. I guess that give a new meaning to the biblical phrase, “a
chasing after the wind”.
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