10 interesting facts about planet Earth
1. Plate tectonics keep the planet comfortable
Earth is the only planet in the Solar System with plate tectonics. The outer crust of the Earth is broken up into regions known as tectonic plates. These are floating on top of the magma interior of the Earth and can move against one another. When two plates collide, one plate can go underneath another.
This process is very important. When microscopic plants in the ocean die, they fall to the bottom of the ocean. Over long periods of time, the remnants of this life, rich in carbon, are carried back into the interior of the Earth and recycled. This pulls carbon out of the atmosphere, which makes sure we don’t get a runaway greenhouse effect, like what happened on Venus.
Without the plate tectonics, there’d be no way to recycle this carbon, and the Earth would overheat.
2. Earth is almost a sphere
The Earth’s shape could be described as an oblate spheroid. It’s kind of like a sphere, but the Earth’s rotation causes the equator to bulge out . What this means is that the measurement from pole to pole is about 43 km less than the diameter of Earth across the equator.
Even though the tallest mountain on Earth is Mount Everest, the feature that’s furthest from the center of the Earth is actually Mount Chimborazo in Ecuador.
3. Earth is mostly iron, oxygen and silicon
If you could separate the Earth out into piles of material, you’d get 32.1 % iron, 30.1% oxygen, 15.1% silicon, and 13.9% magnesium. Of course, most of this iron is actually down at the core of the Earth. If you could actually get down and sample the core, it would be 88% iron. 47% of the Earth’s crust consists of oxygen.
4. 70% of the Earth’s surface is covered in water
When astronauts first went into the space, they looked back at the Earth with human eyes for the first time, and called our home the Blue Planet. And it’s no surprise. 70% of our planet is covered with oceans. The remaining 30% is the solid ground, rising above sea level.
5. The Earth’s atmosphere extends out to 10,000 km
The atmosphere is thickest within the first 50 km or so, but it actually reaches out to about 10,000 km above the surface of the planet. This outermost layer of the atmosphere is called the exosphere, and starts about 500 km above the surface of the Earth. As we said, it goes all the way up to 10,000 km above the surface. At this point, free-moving particles can actually escape the pull of Earth’s gravity, and be blown away by the Sun’s solar wind.
But this high atmosphere is extremely thin. The bulk of the Earth’s atmosphere is down near the Earth itself. In fact, 75% of the Earth’s atmosphere is contained within the first 11 km above the planet’s surface.
Want more planet Earth facts? We’re halfway through. Here come 5 more.
6. The Earth’s molten iron core creates a magnetic field
The Earth is like a great big magnet, with poles at the top and bottom of the planet, near to the actual geographic poles. This magnetic field extends from the surface of the Earth out thousands of kilometers – a region called the magnetosphere.
Be grateful for the magnetosphere. Without it particles from the Sun’s solar wind would hit the Earth directly, exposing the surface of the planet to significant amounts of radiation. Instead, the magnetosphere channels the solar wind around the Earth, protecting us from harm.
Scientists think that the magnetic field is generated by the molten outer core of the Earth, where heat creates convection motions of conducting materials. This generates electric currents that create the magnetic field.
7. Earth doesn’t take 24 hours to rotate on its axis
It’s actually 23 hours, 56 minutes and 4 seconds. This is the amount of time it takes for the Earth to completely rotate around its axis; astronomers call this a sidereal day. Now wait a second, that means a day is 4 minutes shorter than we think it is. You’d think that time would add up, day by day, and within a few months, day would be night, and night would be day.
Remember that the Earth orbits around the Sun. Every day, the Sun moves compared to the background stars by about 1° – about the size of the Moon in the sky. And so, if you add up that little motion from the Sun that we see because the Earth is orbiting around it, as well as the rotation on its axis, you get a total of 24 hours. Now that sounds like the day we know.
8. A year on Earth isn’t 365 days
It’s actually 365.2564 days. It’s this extra .2564 days that creates the need for leap years. That’s why we tack on an extra day in February every year divisible by 4 – 2004, 2008, etc – unless it’s divisible by 100 (1900, 2100, etc)… unless it’s divisible by 400 (1600, 2000, etc).
9. Earth has 1 moon and 2 co-orbital satellites
As you’re probably aware, Earth has 1 moon (The Moon). But did you know there are 2 additional asteroids locked into a co-orbital orbits with Earth? They’re called 3753 Cruithne and 2002 AA29. We won’t go into too much detail about the Moon, I’m sure you’ve heard all about it.
3753 Cruithne is 5 km across, and sometimes called Earth’s second moon. It doesn’t actually orbit the Earth, but has a synchronized orbit with our home planet. It has an orbit that makes it look like it’s following the Earth in orbit, but it’s actually following its own, distinct path around the Sun.
2002 AA29 is only 60 meters across, and makes a horseshoe orbit around the Earth that brings it close to the planet every 95 years. In about 600 years, it will appear to circle Earth in a quasi-satellite orbit. Scientists have suggested that it might make a good target for a space exploration mission.
10. Earth is the only planet known to have life
We’ve discovered past evidence of water on Mars, and the building blocks of life on Saturn’s moon Titan. We can see amino acids in nebulae in deep space. But Earth is the only place life has actually been discovered.
But if there’s life on other planets, scientists are building the experiments that will help find it. A new rover called the Mars Science Laboratory will be heading to Mars in the next few years, equipped with experiments that can detect life in the soil on the Red Planet. Giant radio dishes scan distant stars, listening for the characteristic signals of intelligent life reaching out across interstellar space. And new space telescopes, such as the European Space Agency’s Darwin mission might be powerful enough to sense the presence of life on other worlds.
Approaching Enceladus near midnight
Cassini approached for its October 19, 2011 flyby of Enceladus from almost directly behind it — only the faintest sliver of crescent is illuminated. In the background, Saturn’s crescent sweeps past as Enceladus grows in Cassini’s view. Credit: NASA / JPL / SSI / animation by Emily Lakdawalla
10 Things You Didn’t Know About Jellyfish
1. Jellyfishes are made up of more than 95% water.
Their bodies are soft and lack a skeletal structure or outer shell. They are delicate and easily damanged. Jellyfishes require water to help support their body and if removed from their aquatic surroundings, they collapse and die.
2. Jellyfish are radially symmetrical.
Jellyfish are symmetrical about a central axis that runs through the length of their body, from the top of their bell to the ends of their tentacles. They have a top and a bottom but they lack a left and right side and as a result differ from many other types of animals (such as mammals, reptiles, fish, birds, and arthropods) which exhibit bilateral symmetry.
3. A jellyfish has a simple digestives system with only one opening.
A jellyfish takes food in through its mouth which is located on the underside if its bell. Food is digested in a sac-like structure called a coelenteron or gastrovascular cavity. Waste material is passed out through the mouth.
4. A common analogy used to describe the delicate way jellyfish pounce through the water likens the jellys’ movements to ‘a simple form of jet propulsion’.
To move forward, jellyfishes take water into their muscular bell and then squirt it out behind them, creating a jet of water that propels the jelly forward. In addition to this form of movement, jellies also drift on water currents to move.
5. Jellyfishes have no brain, no blood, and no nervous system.
Their senses are primitive and consist of a neural net, eye spots that can sense light from dark, and chemosensory pits that help them identify potential prey.
6. A jellyfishes’ body consists of three layers.
The outer layer is called the epidermis, the inner layer which lines the gastrovascular cavity is called the gastrodermis, and the middle layer consists of a thick substance called the mesoglea.
7. Thousands of nematocytes are located on the tentacles, feeding arms, and mouth of a jellyfish.
Nenatocysts consist of a capsule that holds a hollow barbed coil, a vemon sac, and chemo-sensitive trigger hairs that detect when something edible brushes against them. When potential prey brushes against the trigger hairs, the nematocytes expel the coiled barb and inject venom into the victim through the hollow thread. The venom immobilizes the prey and the jellyfish uses its oral arms to move the prey into its mouth where it is passed through to the coelenteron for digestion.
8. Jellyfish belong to the Phylum Cnidaria.
This group of animals, all radially symmetrical, includes corals, sea anemones, hydras, and jellyfish.
9. There are about 200 species of True Jellyfishes.
True Jellyfish are species belonging to the Class Scyphozoa. Examples of True Jellyfish include Moon Jellies, Mediterranean Jellyfish, Sea Nettles, Lion’s Mane Jellyfish, Blue Jellies, and many other lesser known species. The Class Cubozoa includes about 20 species not considered to be True Jellyfish. The Class Cubozoa is also referred to as box jellyfish. The most imfamous of the Cubozoa is the Sea Wasp, a creature with a deadly sting that inhabits the waters off the coast of Australia.
10. The species Craspedacusta sowerbii is sometimes referred to as the only species of freshwater jellyfish, although it is not a true jellyfish.
Craspedacusta sowerbii belongs to the Class Hydrozoa (the group of animals that includes the hydra), not the Class Scyphozoa.
(Source: animalgifsblog)
Happy Equinox
Hundreds of pictures of Earth, each taken at about 6AM , showing the terminator - the day/night line - over the course of one year (2010sep-2011sep).
Taken by METEOSAT-9 Earth-observing satellite.
Watch the Video here
Credit: NASA Earth Observatory
Top 10 Amazing Moon Facts
1. The Big Whack
The moon formed as a result of a collision known as the Giant Impact or the Big Whack, scientists figure. It went like this: A giant Mars-sized object hit Earth 4.6 billion years ago shortly after the birth of the sun and the solar system. A cloud of vaporized rock was kicked up (a mix of Earth and the other object) and went into orbit around Earth. The cloud cooled and condensed into a ring of small, solid bodies, which then gathered together, forming the moon.
2. Earth makes the moon rise
Each day, though not at the same time, the moon comes up in the East and goes down in the West — much like the sun and other stars and for the same reason Earth rotates, on its axis, toward the East, pulling celestial objects into view and then forcing them to slip away. The moon also makes an orbital trip around Earth once every 29.5 days. In the sky, this gradual movement is eastward, though it’s not perceptible during any given observing session. It is, however, why the moon rises later each day, by about 50 minutes on average. That also explains why the moon sometimes rises in the evening and us up during the night, while at other times it’s up only or mostly during the day.
3. No dark side
Contrary to what you might have heard, there is no “dark side” of the moon. There is, however, a “far side” that we can’t see from Earth. Here’s why: Long ago, the Earth’s gravitational effects slowed the moon’s rotation about its axis. Once the moon’s rotation slowed enough to match its orbital period (the time it takes the moon to go around Earth) the effect stabilized. So the moon goes around the Earth once and spins on its axis once, all in the same amount of time, and it shows us just one face the whole time.
4. Gravity is much weaker
The moon is about 27 percent the size of Earth and far less massive. Gravity on the moon is only about 1/6 of that on Earth. If you drop a rock on the moon, it falls more slowly (and astronauts can hope much higher). If you weigh 150 pounds on Earth, you’d weigh 25 pounds on the moon.
5. Bigger and smaller full moons
The moon’s orbit around Earth is an oval, not a circle, so the distance between the center of Earth and the moon’s center varies throughout each orbit. At perigee (PEHR uh jee), when the moon is closest to Earth, that distance is 225,740 miles (363,300 kilometers). At apogee (AP uh jee), the farthest position, the distance is 251,970 miles (405,500 kilometers).
6. Pockmarked history
The craters on the moon reveal its violent history. Because there is almost no atmosphere and little activity inside the moon, the crater trace a record of impacts back billions of years (unlike Earth, which would have been just as violent back then, but the craters have all been weathered away or folded back into the planet). By dating the moon’s many craters, scientists figured out that the moon (and Earth) underwent a Late Heavy Bombardment around 4 billion years ago. The latest thinking on this pummeling is that life may have survived it, if biology had gotten a foothold that early.
7. Not round
The moon is not round (or spherical). Instead, it’s shaped like an egg. If you go outside and look up at the moon, one of the small ends is pointing right at you. And the moon’s center of mass is not at the geometric center of the satellite; it’s about 1.2 miles (2 kilometers) off-center. Earth, likewise, bulges in its midsection.
8. Caution! Moonquakes
Apollo astronauts used seismometers during their visits to the moon and discovered that the gray orb isn’t a totally dead place, geologically speaking. Small moonquakes, originating several miles (kilometers) below the surface, are thought to be caused by the gravitational pull of Earth. Sometimes tiny fractures appear at the surface, and gas escapes.
9. Tugging on the oceans
Tides on Earth are caused mostly by the moon (the sun has a smaller effect). Here’s how it works: The moon’s gravity pulls on Earth’s oceans. High tide aligns with the moon as Earth spins underneath. Another high tide occurs on the opposite side of the planet because gravity pulls Earth toward the moon more than it pulls the water.
10. Ciao, Luna!
As you read this, the moon is moving away from us. Each year, the moon steals some of Earth’s rotational energy, and uses it to propel itself about 1.6 inches (4 centimeters) higher in its orbit. Researchers say that when it formed about 4.6 billion years ago, the moon was about 14,000 miles (22,530 kilometers) from Earth. It’s now more than 280,000 miles, or 450,000 kilometers away. Meanwhile, Earth’s rotation rate is slowing down — our days are getting longer and longer. Eventually, our planet’s tidal bulges will be assembled along an imaginary line running through the centers of both Earth and the moon, and our planetary rotational change will pretty much cease. Earth’s day will be a month long. When this happens, billions of years from now, the terrestrial month will be longer — about 40 of our current days — because during all this time the moon will continue moving away.;
(Source: livescience.com)
Top 10 Biggest Brain Damaging Habits
1. No Breakfast
People who do not take breakfast are going to have a lower blood sugar level.This leads to an insufficient supply of nutrients to the brain causing brain degeneration.
2. Overreacting
It causes hardening of the brain arteries, leading to a decrease in mental power.
3. Smoking
It causes multiple brain shrinkage and may lead to Alzheimer disease.
4. High Sugar consumption
Too much sugar will interrupt the absorption of proteins and nutrients causing malnutrition and may interfere with brain development.
5. Air Pollution
The brain is the largest oxygen consumer in our body. Inhaling polluted air decreases the supply of oxygen to the brain, bringing about a decrease in brain efficiency.
6. Sleep Deprivation
Sleep allows our brain to rest. Long term deprivation from sleep will accelerate the death of brain
7. Head covered while sleeping
Sleeping with the head covered, increases the concentration of carbon dioxide and decrease concentration of oxygen that may lead to brain damaging effects.
8. Working your brain during illness
Working hard or studying with sickness may lead to a decrease in effectiveness of the brain as well as damage the brain.
9. Talking Rarely
Intellectual conversations will promote the efficiency of the brain.
10. Lacking in stimulating thoughts
Thinking is the best way to train our brain, lacking in brain stimulation thoughts may cause brain shrinkage.
20 Things You Didn’t Know About Fire
1 Fire is an event, not a thing. Heating wood or other fuel releases volatile vapors that can rapidly combust with oxygen in the air; the resulting incandescent bloom of gas further heats the fuel, releasing more vapors and perpetuating the cycle.
2 Most of the fuels we use derive their energy from trapped solar rays. In photosynthesis, sunlight and heat make chemical energy (in the form of wood or fossil fuel); fire uses chemical energy to produce light and heat.
3 So a bonfire is basically a tree running in reverse.
4 Assuming stable fuel, heat, and oxygen levels, a typical house fire will double in size every minute.
5 Earth is the only known planet where fire can burn. Everywhere else: Not enough oxygen.
6 Conversely, the more oxygen, the hotter the fire. Air is 21 percent oxygen; combine pure oxygen with acetylene, a chemical relative of methane, and you get an oxyacetylene welding torch that burns at over 5,500 degrees Fahrenheit—the hottest fire you are likely to encounter.
7 Oxygen supply influences the color of the flame. A low-oxygen fire contains lots of uncombusted fuel particles and will give off a yellow glow. A high-oxygen fire burns blue.
8 So candle flames are blue at the bottom because that’s where they take up fresh air, and yellow at the top because the rising fumes from below partly suffocate the upper part of the flame.
9 Fire makes water? It’s true. Place a cold spoon over a candle and you will observe the water vapor condense on the metal…
10 …because wax—like most organic materials, including wood and gasoline—contains hydrogen, which bonds with oxygen to make H2O when it burns. Water comes out your car’s tailpipe, too.
11 We’ve been at this a long time: Charred bones and wood ash indicate that early hominids were tending thefirst intentional fires more than 400,000 years ago.
12 Nature’s been at it awhile, too. A coal seam about 140 miles north of Sydney, Australia, has been burning by some estimates for 500,000 years.
13 The ancient Greeks started fire with concentrated sunlight. A parabolic mirror that focuses solar rays is still used to ignite the Olympic torch.
14 Every 52 years, when their calendar completed a cycle, the Aztecs would extinguish every flame in the empire. The high priest would start a new fire on the ripped-open chest of a sacrificial victim. Fires fed from this flame would be distributed throughout the land.
15 Good burn: The 1666 Great Fire of London destroyed 80 percent of the city but also ended an outbreak of bubonic plague that had killed more than 65,000 people the previous year. The fire fried the rats and fleas that carried Yersinia pestis, the plague-causing bacterium.
16 The Peshtigo Fire in Wisconsin was the second deadliest blaze in United States history, taking 1,200 lives—four times as many as the Great Chicago Fire. Both conflagrations broke out on the same day: October 8, 1871.
17 America’s deadliest fire took place April 27, 1865, aboard the steamship Sultana. Among other passengers were 1,500 recently released Union prisoners traveling home up the Mississippi when the boilers exploded. The ship was six times over capacity, which helps explain the death toll of 1,547.
18 The Black Dragon Fire of 1987, the largest wildfire in modern times, burned some 20 million acres across China and the Soviet Union, an area about the size of South Carolina.
19 Spontaneous combustion is real. Some fuel sources can generate their own heat—by rotting, for instance. Pistachios have so much natural oil and are so prone to heat-generating fat decomposition that the International Maritime Dangerous Goods Code regards them as dangerous.
20 Haystacks, compost heaps, and even piles of old newspapers and magazines can also burst into flame. A good reason to recycle DISCOVER when you are done.
