There is enough DNA in the average person’s body to stretch from
the sun to Pluto and back .....17 times
The human
genome (the genetic code in each human
cell) contains 23 DNA molecules [called chromosomes], each containing from
500,000 to 2.5 million nucleotide pairs. DNA molecules of this size are 1.7 to
8.5 cm long when uncoiled about 5 cm on average. There are
about 37 trillion cells in the
human body, so if you were to uncoil all of the DNA encase
Water can boil and freeze at the same time
Water can boil and freeze at the same time
Seriously, it's called the 'triple point', and it occurs when the temperature and pressure is just
right for the three phases [gas, liquid, and solid] of a substance to coexist
in thermodynamic equilibrium. This
video shows
cyclohexane in a vacuum.
The Eiffel Tower can be 15 cm taller during the summer
When a substance is heated up, its
particles move more and it takes up a larger volume – this is known as thermal
expansion. Conversely, a drop in temperature causes it to contract again. The
mercury level inside a thermometer, for example, rises and falls as the
mercury’s volume changes with the ambient temperature. This effect is most
dramatic in gases but occurs in liquids and solids such as iron too. For this
reason, large structures such as bridges are built with expansion joints which
allow them some leeway to expand and contract without causing any damage.
20% of Earth’s oxygen is
produced by the Amazon rainforest
Our atmosphere is made up of roughly
78 per cent nitrogen and 21 per cent oxygen, with various other gases present
in small amounts. The vast majority ofliving organisms on Earth need oxygen to
survive, converting it into carbon dioxide as they breathe. Thankfully, plants
continually replenish our planet’s oxygen levels through photosynthesis. During
this process, carbon dioxide and water are converted into energy, releasing
oxygen as a by-product. Covering 5.5 million square kilometres (2.1 million
square miles), the Amazon rainforest cycles a significant proportion of the
Earth’s oxygen, absorbing large quantities of carbon dioxide at the same time.
Some metals are so reactive that they explode on contact with water
There are certain metals – including potassium,
sodium, lithium, rubidium and caesium – that are so reactive that they oxidise
(or tarnish) instantly when exposed to air. They can even produce explosions
when dropped in water! All elements strive to be chemically stable – in other
words, to have a full outer electron shell. To achieve this, metals tend to
shed electrons. The alkali metals have only one electron on their outer shell,
making them ultra-keen to pass on this unwanted passenger to another element
via bonding. As a result they form compounds with other elements so readily
that they don’t exist independently in nature.
A teaspoonful of neutron star would weigh 6 billion tons
A neutron star is the remnants of a
massive star that has run out of fuel. The dying star explodes in a supernova
while its core collapses in on itself due to gravity, forming a super-dense
neutron star. Astronomers measure the mind-bogglingly large masses of stars or
galaxies in solar masses, with one solar mass equal to the Sun’s mass (that is,
2 x 1030 kilograms/4.4 x 1030 pounds). Typical neutron stars have a mass of up
to three solar masses, which is crammed into a sphere with a radius of
approximately ten kilometres (6.2 miles) – resulting in some of the densest
matter in the known universe.
Hawaii moves 7.5cm closer to Alaska every year
The Earth’s crust is split into
gigantic pieces called tectonic plates. These plates are in constant motion,
propelled by currents in the Earth’s upper mantle. Hot, less-dense rock rises
before cooling and sinking, giving rise to circular convection currents which
act like giant conveyor belts, slowly shifting the tectonic plates above them.
Hawaii sits in the middle of the Pacific Plate, which is slowly drifting
north-west towards the North American Plate, back to Alaska. The plates’ pace
is comparable to the speed at which our fingernails grow.
palaeontologists
can roughly guess its age. Carbon dating estimates a fossil’s age more
precisely, based on the rate of decay of radioactive elements such as
carbon-14.
In 2.3 billion years it
will be too hot for life to exist on Earth
Over the coming hundreds of millions
of years, the Sun will continue to get progressively brighter and hotter. In
just over 2 billion years, temperatures will be high enough to evaporate our
oceans, making life on Earth impossible. Our planet will become a vast desert
similar to Mars today. As it expands into a red giant in the following few
billion years, scientists predict that the Sun will finally engulf Earth
altogether, spelling the definite end for our planet.
Polar bears are nearly undetectable by infrared cameras
Thermal cameras detect the heat lost
by a subject as infrared, but polar bears are experts at conserving heat. The
bears keep warm due to a thick layer of blubber under the skin. Add to this a
dense fur coat and they can endure the chilliest Arctic day.
It takes 8 minutes, 19 seconds for light to travel from the Sun to the Earth
In space, light travels at 300,000
kilometres (186,000 miles) per second. Even at this breakneck speed, covering
the 150 million odd kilometres (93 million miles) between us and the Sun takes
considerable time. And eight minutes is still very little compared to the five
and a half hours it takes for the Sun’s light to reach Pluto.
Stomach acid is strong enough to dissolve stainless steel
Your stomach digests food thanks to
highly corrosive hydrochloric acid with a pH of 2 to 3. This acid also attacks
your stomach lining, which protects itself by secreting an alkali bicarbonate
solution. The lining still needs to be replaced continually, and it entirely
renews itself every four
Venus is the only planet to spin clockwise
Our Solar System started off as a
swirling cloud of dust and gas which eventually collapsed into a spinning disc
with the Sun at its centre. Because of this common origin, all the planets move
around the Sun in the same direction and on roughly the same plane. They also
all spin in the same direction (counterclockwise if observed from ‘above’) –
except Uranus and Venus. Uranus spins on its side, while Venus defiantly spins
in the complete opposite direction. The most likely cause of these planetary
oddballs are gigantic asteroids which knocked them off course in the distant
past.
A flea can accelerate faster than the Space Shuttle
A jumping flea reaches dizzying
heights of about eight centimetres (three inches) in a millisecond.
Acceleration is the change in speed of an object over time, often measured in
‘g’s, with one g equal to the acceleration caused bygravity on Earth (9.8
metres/32.2 feet per square second). Fleas experience 100 g, while the Space
Shuttle peaked at around 5 g. The flea’s secret is a stretchy rubber-like
protein which allows it to store and release energy like a spring.
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