What are some of the most interesting scientific facts known to you?

• Saturn would float if you would put it in water.
• If you would place a pinhead sized piece of the Sun's core on the Earth you would die from standing within 145 km (90 miles) from it.
• Only 5% of the universe is made up of normal matter, 25% is dark matter and 70% is dark energy.
• The Sun is 400 times larger than the Moon but is 400 times further away from Earth making them appear the same size.
• Venus does not have any seasons at all.
• 1 year on Mercury consists of less than 2 days on Earth.
• Helium turns into a solid at 0.95K at 25 atmospheres.
• The coldest place on Earth is in Wolfgang Ketterles laboratory in Massachusetts. But still they couldn't attain an absolute zero.
• The pistol star is the most luminous star known 10 million times the brightness of the Sun.
• All the planets are the same age: 4.544 billion years.
• 8000 stars are visible with naked eye from Earth. 4000 in each hemisphere, 2000 at daylight and 2000 at night.
• 90-99% of all normal matter in the universe is hydrogen.
• Only 55% of all Americans knows that the Sun is a star.
• All the coal, oil, gas, wood and fuel on Earth would only keep the Sun burning for few days.
• A full moon is nine times brighter than a half moon.
• When the Moon is directly above your head or if you stand at the equator, you weight slightly less.
• Just after the Big Bang, everything in the universe was in liquid form.
• Every year, the Moon is moving away from Earth by 3.8 centimeters.
• The Moon spins around its axis in the same time it goes one lap around the Earth which makes us always see the same side of it.
• While in space astronomers can get taller, but at the same time their hearts can get smaller.
• Mars surface is covered with iron oxide (rust).
• Only half a billionth of the energy released by the Sun reaches Earth.
• The light emitting from the Sun is actually 30,000 years old.
• The closest black hole to Earth is only 1.600 light-years away.
• There are 10^24 stars in the universe.
• Any free-moving liquid in outer space (at zero gravity) will form itself into a sphere due to surface tension.
• The odds of being killed by falling space debris is 1 in 5 billion.
• Around 1% of the sun’s mass is oxygen.

Edit: Thanks for the response guys. I thought of adding few more facts mainly regarding the life science. Have fun reading.

• Adult lungs have a surface area of around 70 square meters.
• Humans have a stage of sleep that features rapid eye movement (REM). REM sleep makes up around 25% of total sleep time and is often when you have your most vivid dreams.
• Your nose and ears continue growing throughout your entire life.
• As well as having unique fingerprints, humans also have unique tongue prints.
• Your sense of smell is around 10000 times more sensitive than your sense of taste.
• The brain uses over a quarter of the oxygen used by the human body.
• Your heart beats around 100000 times a day, 36500000 times a year and over a billion times if you live beyond 30.
• Rats breed so quickly that in just 18 months, 2 rats could have created over 1 million relatives.
• The blue whale can produce the loudest sound of any animal. At 188 decibels, the noise can be detected over 800 kilometers away.
• Horses and cows can sleep while standing up.
• Giant Arctic jellyfish have tentacles that can reach over 36 meters in length.
• Locusts have leg muscles that are about 1000 times more powerful than an equal weight of human muscle.
• Humming birds are so agile and have such good control that they can fly backwards.
• The horn of a rhinoceros is made from compacted hair rather than bone or another substance.
• Sharks have the biggest eggs in the world.
• Unlike humans, sheep and cows have four chambered stomach, each chamber helps them digest the food they eat.
• Despite the white, fluffy appearance of Polar Bears fur (which is transparent), it actually has black skin.
• Mosquitoes can be annoying insects but did you know that it's only the female mosquito that actually bites humans.
• Cats use their whiskers to check whether a space is too small for them to fit through or not.
• Mosquitoes like the scent of estrogen, thus women get bitten more often than men do.
• If you pour a handful of salt into a full glass of water, the water level will actually go down rather than overflowing the glass.
• The only letter that doesn't appear on the periodic table is J.
• Bee stings are acidic while wasp stings are alkaline.
• One bucket full of water contains more atoms than there are bucketfuls of water in the Atlantic ocean.
• Hydro-fluoric acid is so corrosive that it will dissolve glass. Although it is corrosive, hydro-fluoric acid is considered to be a 'weak acid'.
• The human body contains enough carbon to provide 'lead' (which is really graphite) for about 9,000 pencils.
• Every year on October 23 from 6:02am to 6:02pm, chemistry students and chemists celebrate Mole Day in honor of Avogadro’s number, the number of carbon atoms in 12 grams of carbon.
• Although oxygen gas is colorless (light refraction aside), both the liquid and solid forms are blue.
• Although it is still debated, it is largely recognized that the word 'chemistry' comes from an Egyptian word meaning 'earth'.
• DNA is flame retard. It does not catch fire.
• Lemons contain more sugar than strawberries, for the same amount of mass.
• Dynamite contains peanuts as its ingredient.
• Talc is the softest substance known.
• Lighter was invented before Match by J.W.Dobereiner.