Gravity is part of
our lives here on Earth, we take it for granted in fact we didn’t
even realise it existed until an apple fell from a tree in front of
Isaac Newton, making him realise it was there. Gravity is much more
than fruit falling from trees, it draws all objects together in
direct proportion to their mass amongst many other things you
probably don’t know. Check out these 6 weird facts about gravity.
Gravity is all in your head
Gravity is pretty
consistent on Earth, but our perception of gravity certainly isn’t.
In April 2011 research suggested that people can judge falling
objects when they are sitting upright better than they can when they
are lying on their side. This, in turn, suggests that our perception
of gravity is less based on our visual clues and more rooted in our
bodies orientation. This could lead to new ways of helping astronauts
deal with microgravity in space.
Back down to Earth is tough
Astronauts are aware
that the switch from the weightlessness of space to the gravity here
on Earth is tough on our bodies. When gravity is absent or reduced
our muscles atrophy and our bones lose bone mass. NASA thinks that
astronauts lose around 1% of bone mass per month in space. When
returning to Earths gravity the body needs time to adjust the heart
must work harder to provide the brain with a constant supply of
blood. Mentally it is also challenging; many astronauts break things
for weeks after returning to Earth, assuming they will be weightless
they simply ‘drop’ them after use!
On a diet? Try moving to Pluto!
Pluto is no longer a
planet, but it still is the best diet in our galaxy! A 68kg person
would only weigh around 4.5kg on Pluto. On the other end of the
scale, Jupiter’s crushing gravity would render this 68kg person
160kg! Mars, the planet humans are most likely to visit only has 38%
of Earths gravitation pull so the person of 68kg would weigh in at
Gravity is lumpy
Even on our planet
gravity is uneven. Earth isn’t a perfect sphere and its mass is
distributed unevenly; uneven mass = uneven gravity. One example of
this is in the Hudson Bay of Canada (shown above) the gravity is
lower than in other regions. A 2007 study has revealed that melting
glaciers are to blame for this, the mass of the melted glaciers have
reduced over time, affecting gravity there.
Bugs are much tougher without gravity
In space, bacteria
are much nastier without the effects of gravity. Salmonella, for
example, the bacteria linked to food poisoning is around 3 times more
potent in microgravity environments. The lack of gravity is believed
to change the activity in genes and proteins in bacteria. Mice fed
this gravity-free salmonella became sicker faster with a much lower
dose of the bacteria. In short bugs on Earth would potentially be
much stronger in space!
Black holes at galaxy centres
Black holes are named because nothing, not even light can escape them, they are the most destructive force in our universe. At the very centre of our galaxy is a massive black hole, named Sagittarius A, it has a mass the same as 3 million Suns. Scary or not, it isn’t really a threat to us here on Earth, it is very calm and a long long way away from us. At times Sagittarius A does put on a show for the universe though, around 300 years ago it sent out a flare of energy. Stars and gas rarely get close enough to Sagittarius A to be in any form of danger, if they did they surely would be swallowed up instantly!