Plate Tectronics

Cut Away of Earth's Crust
Cut away schematic of the Earth, By derivative work: Anasofiapaixao Earth_internal_structure.png: USGS (Earth_internal_structure.png) [Public domain], via Wikimedia Commons
According to the theory of plate tectonics, the earth’s lithosphere contains plates that move gradually over the asthenosphere. The major geological processes, such as earthquakes and the formation of volcanoes and mountain belts occur at the places of the interaction of these plates. As a result, the following changes have been witnessed in the earth’s geology:

The formation of the Himalayas – when the Indian subplate burrowed under the Eurasian plate, or the formation of the Appalachian Mountains, when the North American and African plates collided. The separation of North America from Europe by the opening of the Atlantic.

The volcanic and seismic activity of the West Coast of the US occurs as a result of grinding of the North American and Pacific plates.
The above mentioned are just a few examples of the effects of plate tectonics. The geological history of earth is littered with such phenomena and processes that have made the Earth how it is today.

The Latest Findings

But as it turns out, such interactions between continental plates is not the only reason for various geological processes. Research led by a joint team of the University of Toronto and University of Aberdeen researchers has achieved an enormous breakthrough! According to the research that uses supercomputers to run a model of the Earth’s upper mantle and crust, the prehistoric geological events could have left deep ‘scars’ that may play a significant role in earthquakes, tsunamis, formation of mountains or ocean trenches and many other ongoing geological processes.

The models created by the researchers indicate that the previous plate boundaries could stay buried deep below the surface of the Earth. These structures, which are no less than many millions of years old, are located far from the current plate boundaries and may cause drastic changes in the surface properties and structure of the interior of the continents.

The researchers went a step further to propose a new map highlighting the ancient geology of the Earth. The ‘perennial plate tectonic map’ explains through illustrations how the prehistoric geological events could affect today’s geological processes. The map is based on the common tectonic map, which is taught in elementary school, but it has been modified to include the concealed, ancient plate boundaries that may be involved in plate tectonic activity in the past as well as the present.

Owing to this recent breakthrough, some major revisions are required to the fundamental idea of plate tectonics. The research paper titled, ‘Lasting mantle scars lead to perennial plate tectonics’ appeared in Nature Communications issue of June 10, 2016.

The Science Behind Earthquakes

We’re all familiar, or at least come across time and again, with the terms tectonic plates, fault lines and seismic zones. But there are quite a few of us who cannot make up the connection between these and basically answer the simple question of what causes earthquakes? How and why the tectonic plates move and what is it beneath the surface of the earth that makes all these hazardous movements to happen’ are two of the most pressing questions related to earthquakes.

Keep reading to get the aforementioned questions answered and get your hands on some essential knowledge about the basics of earthquakes.

Tectonic plates and fault lines

The planet Earth is composed of four layers, inner and outer core, mantle and the crust which is the outermost core. The outer/top-most part of the plastic-like mantle and crust make up a thin layer over the surface of the earth. In order to understand tectonic plates, it is essential to know that this thin outer layer is not a single piece; rather it is a number of pieces joined together. These pieces of crust, called tectonic plates, together with the block of the earth right beneath them, are not static; they move and slide at their boundaries against each other.  These boundaries are referred to as ‘plate boundaries’. When we say the word fault line, we are basically referring to these boundaries collectively. It is here that the blocks of earth slide past each other causing the earthquake.

So, how does an earthquake happen?

As mentioned above, tectonic plates are not static. As their boundaries are joined or stuck with each other, it is easier for the plate itself to move than the respective boundary to move at the same pace because of higher friction. As plates move, pressure builds up on the plate boundaries causing energy to be increasingly stored in them. It is only when the pressure build-up from the plates’ movement overcomes the friction between the jagged plate boundaries that they are unstuck and slide past each other. This releases the energy being stored for far too long. The radiation of this released energy across the tectonic plate is what is scientifically called ‘Seismic Waves’. As these waves move past the earth, they shake the earth. Upon reaching the surface, they shake the surface of the earth.

The area below the surface of the earth, the origin of the earthquake, is called the hypocenter. Its corresponding area right on the surface of the earth is called epicenter. The path that the seismic waves travel from the hypocenter and epicenter is basically the fault plane, the movement of which against the neighboring plane causes the earthquake.

Breaking misconceptions

One major misconception about earthquakes is that the tectonic plates move only before/during the earthquake. This is not true. It is totally natural for the tectonic plates to keep having slight movements at all times, which do not escalate into an earthquake. As established above, it is only when the movement of tectonic plates is significant enough to overpower the friction holding the boundaries together that earthquake happens.

Universe Contains More Galaxies Than Thought

Galaxies all Over UsJust how large is the universe? Far larger than initially thought. Astronomers have discovered that there are at least 10 times as many galaxies in the universe.

Using data from the NASA/ESA Hubble Space Telescopes, astronomers have been able to perform an accurate census of the number of galaxies in the universe. In the mid-1990s, it was estimated that the observable universe contained between 100 to 200 billion galaxies. However, the latest data and images gathered have revised that number upwards significantly to the tune of over two trillion galaxies.

The team of researchers used deep-space images from the Hubble and a number of sources of data to make accurate measurements of the number of galaxies that existed at different times in the universe’s history. They determined that approximately 90% of galaxies are too faint and far away to be seen.

“It boggles the mind that over 90% of the galaxies in the Universe have yet to be studied,” lead researcher Christopher Conselice of the University of Nottingham, UK, said in a statement. “Who knows what interesting properties we will find when we observe these galaxies with the next generation of telescopes.”

In order to observe the galaxies, the team of researchers had to compile data going back 13 billion years ago because they were studying parts of the universe that were up to 13 billion light-years away. This allowed them to observe the evolution of the universe and conclude that the early universe contained more galaxies than it does today. Some of the small dwarf galaxies merged together to form larger galaxies as time went by.

“This gives us a verification of the so-called top-down formation of structure in the Universe,” Conselice said.

The confirmation that the number of galaxies has been decreasing as time has progressed also helps to explain why the night sky is so dark. There was a theory that the night sky should be permanently light given that the universe is filled with an infinite number of stars. However, this theory was created before the understanding of the universe’s dynamic nature.

“This is very surprising as we know that, over the 13.7 billion years of cosmic evolution since the Big Bang, galaxies have been growing through star formation and mergers with other galaxies,” Conselice said in a separate statement. “Finding more galaxies in the past implies that significant evolution must have occurred to reduce their number through the extensive merging of systems.”

Just think, there could have been a planet with intelligent life on it similar to ours in a galaxy 13 billion light-years away (that’s 13 billion years ago) and we will never know!

If It Weren’t For This, the Stars Wouldn’t Have Their Names!

We’ve all heard the stories of the North Star guiding sailors through the mighty oceans to their destinations. We’ve got songs and poems based on stars – remember chanting “like a diamond in the sky” every time you were asked to recite a nursery rhyme?

Star Cluster
A Star Cluster

Stars have been around for centuries and have been the point of fascination for as long as we humans have existed.

But were you aware of the fact that every star that you see shining in the sky on a clear night actually has a name?

Stars were given names since the ancient times. It gave astronomers the opportunity to study select stars in a precise manner.

Why else do you think the North Star is called so?

While some stars get proper names, others are named using a catalog number as and when they are observed by someone. However, the interesting question remains:

How do stars get their names?

Let’s find that out.

In ancient times the constellations were seen as patterns that resembled objects, animals, or people – some constellations like “Orion” even became a representation of the Greek myth of Orion the Hunter. This is one of the major reasons why most stars have been named in a mix of Latin and Greek languages. There is Bellatrix and Cappella (Latin), Canopus and Alcyone (Greek), and Alnair and Caph (Arabic), among various other stars.

Can you name a few popular stars? Let us give you a start; there’s the Sirius and Rigel – how many more can you think of?

But giving fancy names to the stars has diminished to a mere act of the past. In today’s world, Stars are mostly assigned a numerical descriptor. The descriptor is reflective of the star’s position in the sky at night. These numbers are generally associated to a catalog. The star catalogs are used to group stars with similar properties or on the basis of the instrument that discovered their radiation initially.

Modern day astronomers often make use of constellations to name the stars. There are 88 officially recognized constellations in the universe. It’s the International Astronomical Union that keeps record and track of the naming of celestial objects. The stars within a constellation are named using Greek alphabets: alpha, beta, gamma, and so on followed by the name of their constellation for scientific recognition. The brightest star called is the “alpha” and the rest follow. Once all Greek letters are used, the remaining stars are assigned numerical designations.

There are a number of stars that have been named since the ancient times, like the Betelgeuse. In Arabic it translates to “the hand of the giant”. Since the Betelgeuse is the brightest star of the Orion constellation, it gets the scientific name Alpha Orionis.

Did you know that the North Star’s actual name is Polaris? It is also sometimes referred to as the Pole Star.

As displeasing to the ears as the modern day names of the stars may sound, thy prove extremely useful in helping astronomers search, study, and learn more about a particular star in the night sky.  These names are internationally agreed upon and used worldwide to avoid confusions.

 

Five Weird Astronomy Theories That Will Make Your Heart Beat Faster

The ancient race of humans used to believe that the earth was flat. So, when various Greek philosophers, Muslim astronomers and other legendary scientists claimed it to be spherical, people were quite shocked. Imagine spending your whole life thinking that the end of the waterfall marks the end of the earth and one can topple right over the edge and into the hands of the monsters if they were not careful. Then, all their beliefs were declared to be baseless. People were surprised, shocked and stunned. However, you will still not be as creeped out by the theory as you are going to be after reading about the following crazy astronomical theories that might or might not be true:

The Theory of Velikovsky

According to Velikovsky – who was not a scientist but still had many theories – all the disastrous happenings mentioned in the bible actually did take place. To drive his point home, he claimed that it was Venus and Mars that were responsible for it. According to his theory, anytime a planet passes too closely to another planet, it brings chaos. He also stated that Venus could actually move backwards to cause destruction and disasters. Though his theory was rejected by scientists, it is still scary to think that any time Venus and Mars get a little too close for comfort, we’re done for.

The Theory about What Lies Beyond the Hubble Volume:

After some findings and researches, many astronomers claim that there are many other universes just like ours and that the solar system is infinite. But this is not the weird part; the weird part about this theory is the belief that each universe contains an earth just like the one we live in and moreover, each earth houses someone who is just like us, talks like us, walks like us and even looks like us. However, for all we know, the “other “us could be a global rock star in one of the other earths, a beggar in the other one or maybe a hard-core criminal in the third one.

The Sun Theory:

While there are many theories that involve the sun, this one is the most frightening of all. You know how we say “the sun is hot” on a scorching summer day? Well, that is nothing compared to how hot the sun will get according to this theory. Scientists believe that the Sun is just young now and stars are known to get hotter as they get older. So, according to this theory, in the next couple of billion years, the sun will be so hot that it might actually boil our homes to nothingness. Perhaps it’s a good thing we won’t be alive to see that day.

Mass Extinction:

The earth might look huge to us from where we stand but some scientists believe that it too has a maximum capacity and range and there will come a time when people will end up overflowing it. The fact wasn’t supported by the fact that by 1800, the human population reached 1 billion in number for the first time. As of 2016, the earth managed to contain 7.2 billion people inside it, practically nullifying this theory.

Now these theories may or may not be true but it sure is terrifying to imagine that a time will come when this earth might boil and get destroyed due to overpopulation or maybe a little hug from Venus might cause chaos on the earth.

All about Comets!

“Can we pretend that airplanes in the night sky are like shooting stars, I could really use a wish right now, wish right now, wish right now”

No, that’s not a quote. It’s actually the lyrics of the song “Airplanes” by rap artist B.o.B ft. Hayley Williams. You’re probably wondering why we would quote this here – well, don’t you EVER look for a shooting star in the night sky?

You bet we all do! And “shooting star” is just a fancy name we’ve come up with for the celestial comets. Now we’re not sure how far the “wishing upon a star” theory is true, but these facts about the comets are definitely legit!

To begin with, comets are composed dominantly of ice particles that are combined with elements of dust, gas, and rock. This is why they are also called dirty snowballs and are often referred to as cosmic snowballs too – it’s all about the ice!  

But where did these comets come from?

There are two basic theories that the astronomers suggest for the origin of these comets. Astronomers believe that comets either come from the Kuiper Belt present in outer space beyond the orbit of Neptune containing countless dormant comets; or the Oort Cloud – an extensive shell of objects formed of ice particles that exists in the furthermost reaches of our solar system. The Oort cloud is believed to be the home of dormant comets.

Which one of them sounds more believable to you?

Just like all the planets, comets orbit in elliptical paths around the sun; but their path is more oblique than that of the planets. These comets even have a halo! It’s called the coma. The coma is formed when the gas and ice in the comet vaporize due to solar radiation forming a halo around the comet as it moves towards the sun.

Coming to the composition of a comet; all comets are made of four basic components. They have a coma, a nucleus, an ion tail, and a dust tail. It is the nucleus that forms the core of the comet and also contains the most of its combined mass. As for the tails, the ion tail of the comet forms due to the solar winds that direct the gas particles in a direction opposite to the sun. The dust tail is composed of rocks and dust that the comet leaves behind as it orbits the sun.

Let’s talk about the celebrity comets. There have been three popular ones to be precise. The Halley’s Comet tops the chart; it is estimated that the comet was first observed in 240 B.C. and it can be seen from Earth’s surface after every 76 years. The comet takes it name after Edmond Halley – the British astronomer.

The other two well-known comets include Comet Hyakutake that was discovered back in 1996, and the Comet Hale-Bopp, which was first observed in the year 1995.

Did you know that currently there are more than three thousand comets that scientists actually know about?

Mighty Tornadoes and What Makes Them So Twisted!

Tornado in California
Twister moving in California

Natural disasters are a grave reminder of how helpless man is against the forces of nature. Tornadoes are just one of the many destructive forces of nature that can uproot you within seconds and throw you around like cardboard chips. Hence, it is important to know and learn about them as much as we can to make sure we are at least better equipped mentally to face the deadly aftermath of this catastrophe.

So what exactly is a tornado?

According to the National Weather Service, a tornado is

“A violently rotating column of air pendant from a thunderstorm cloud and touching the ground”

It is basically a moving column of violent air that is connected with the ground and a cumulonimbus cloud (in most cases) as the same time. In the United States, there are around a 100,000 thunderstorms that form within a year’s’ time; and there are 600 to 1,000 thunderstorms each year that bring tornadoes with them.

Tornadoes can form in almost any state; but the states that are most affected include Texas, South Dakota, Oklahoma, Nebraska, Missouri, Mississippi, Louisiana, Kansas, Iowa, Indiana, Illinois, Georgia, Florida, Arkansas, and Alabama.

So how much do you know about tornadoes? Let’s find out!

These destructive machines of nature are a weather-related event. Normally, a tornado’s path of expected to be around four hundred yards wide and four miles long. But don’t be fooled! Some tornadoes may surprise you with a hundred-mile long path and about a mile wide! They can reach a height of about 60,000 feet – you think the Giant in “Jack and the Beanstalk” would have been that tall or is it just us?

A tornado can move at an average speed of between twenty five and forty miles per hour, but there are some that can chase you at an astounding seventy mile per hour speed. And that’s just the tornado; the winds inside it have a speed of their own – let’s say they can swirl around at almost three hundred miles per hour. There is no way you can beat that!

If we observe the average stay of a tornado on the ground, it is hardly ever more than an interval of about five minutes, but the tornado keeps returning to the ground, and the touchdown could be several times in a row!   

So which direction do these tornadoes move in? Allow us to enlighten you.

These tornadoes really have a strong sense of direction – we mean, how else would the tornadoes rotate clockwise in the southern hemisphere and counterclockwise in the northern hemisphere? Also most tornadoes are founding moving to the northeast from the southwest.

Another interesting fact about tornadoes is that a majority of them occur in the time span between 3PM and 7PM. Although these tornadoes occur across the globe in many different countries, United States gets the largest share of them, and they’re also the most destructive ones to occur. On an average, the United States faces almost eight hundred tornadoes each year.

Do you know how many people are killed by tornadoes each year? The figure comes around ONE HUNDRED!

 

Is There Anything Scarier than a Tsunami?

What on earth scares you? (Pun intended).

Many would answer war, hunger, terrorism, poverty, and even death. Things like these make the havoc wrecked by natural disasters quite puny. Every once in awhile we hear about a cyclone killing hundreds, a volcanic eruption that destroys villages, a severe earthquake that brings mass destruction and deaths, or a tsunami that just sweeps away entire towns with it.

Natural disasters are a reminder that we are only human. That even the best defenses cannot save us from the forces of nature. And the tsunami happens to be one of the most fascinating natural disasters to study.

Ever wondered what causes a tsunami?

A tsunami is a sequence of oceanic waves forming due to an earthquake, a volcanic eruption, or a landslide that occurs under the surface of the sea. The underwater world is a mysterious one and yes they do have mountains down there too! There are times, although rare when these waves are the result of the impact of a giant meteor that falls into the ocean.

The waves of a tsunami can reach a height of or more than One Hundred Feet!

Tsunami is a Japanese word. It translates to “harbor wave” (tsu=harbor + name=wave). The Pacific Ocean has the “Ring of Fire” which is the most tsunami prone region in the entire world, with around 80% tsunamis occurring there – a reason why Japan has a long history of tsunamis.

However, the worst tsunami in the history occurred in the Indian Ocean back in 2004. It was caused by an earthquake that resulted from the energy radiation of twenty three thousand atomic bombs. The waves originating from the core of this tsunami wrecked havoc on the coastal areas of 11 different countries that included India, Bangladesh, Sri Lanka, Thailand, Indonesia, Malaysia, Myanmar, Maldives, South Africa, Kenya, and Somalia. The death toll reached a tragic count of 283,000 lives.   

It is observed that the first wave of the tsunami is usually not the most powerful one; the ones that follow gain strength, height, and destructive momentum. The average speed of a tsunami has been recorded around five hundred miles per hour – at that speed it can almost compete a jet plane!

In the United States, the states that are most exposed to the risk of tsunami include Washington, Oregon, Hawaii, California, and Alaska. Out of these states, it is Hawaii that is most prone to the tsunami. On an average, the state gets at least one tsunami each year and there is a severe one that hits them in every seven years. The worst tsunami to ever hit Hawaii was one that occurred back in 1946. It hit the Hilo Island at a speed of five hundred miles per hour with waves as much as thirty feet high!

Tsunamis don’t lose their energy as they travel. They could cross entire oceans without losing their momentum. Unlike other natural disasters, it is possible to predict the estimated time for the tsunami to hit. Scientists can derive that based on calculation related to water depth, distances, and the timing of the cause.

If you’re ever caught in a tsunami, don’t swim! Rather try and get hold of a floating object that can help you be carried away by the waves, hopefully to a safer place.

What Do You Know about Saturn’s Rings?

Saturn's Rings
The attenuation of 0.94-, 3.6-, and 13-centimeter signals sent by Cassini through the rings to Earth shows abundance of particles in the rings of Saturn

Our universe is full of surprises and it’s an absolutely divine work of art. There’s a lot we, the petty humans have already discovered about this grand realm – and one out of that overflowing trove of information is the fact that Saturn has rings surrounding its circumference.

Now how is that fair? Earth gets water and Saturn gets RINGS!

Not that we’re not grateful for the water, but if Earth wanted rings too just what could it do to get those?

Here’s all you need to know about the Saturn Rings:

It was Galileo Galilei, the famous Italian astronomer who first discovered the Saturn Rings back in 1610 – he thought they resembled arms or handles! Unfortunately, Galilei’s telescope wasn’t powerful enough to figure out what they were exactly. Enter comes Christiaan Huygens – the Dutch astronomer who declared that they were actually a flat, thin ring.

Later, with the advent of more powerful telescopes it became evident that Saturn wasn’t just surrounded by one thin, flat ring. In fact, there were many. The largest one out of those was estimated to be around two hundred times the size of the planet’s own diameter which is approximately, 116,464 kilometers. 

These rings are alphabetically in the order of their discovery. Most of these rings are generally not more than thirty feet in thickness. There are four core rings that work out from the planet itself. They are named D, C, B, and A. The innermost ring D is the faintest and the outermost is big enough to house a billion Earths! No, we’re not kidding.

Most of the fainter rings were discovered with the improvement in the telescopes with technological advances. It was Voyager 1 – the NASA space probe launched in 1977 that discovered the Ring D back in 1980. After Ring A is the Ring F, followed by ring G and E.

The rings are separated by gaps and structures. While some gaps are justified by the presence of the smaller moons of Saturn, others still have the astronomers confused. These rings are all typically quite close to each other; however the rings B and A are separated by the Cassini Division – a span of 4,700 kilometers.

Did you know that Saturn is not the only planet with rings? Neptune, Uranus, Jupiter also have rings! However, their rings aren’t so much visible because they do not have the moon span of 282,000 kilometers.

So what exactly are these rings made of?

Astronomers and scientists reveal that the rings surrounding Saturn are made up of particles. These particles range in size – some as small as grain and others as big as the size of the mountains. Most of these particles are made of ice – yes water-ice!

It is the rings that draw in particles floating in outer space and at times these particles are rocky meteoroids too.

Still wondering if rings composed of ice particles amount to the presence of water on and/or around the planet. What do you think?

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Giant Magellan Telescope

Giant Magellan Telescope

The Giant Magellan Telescope (GMT) is a planned telescope that will be the first in a new class of Extremely Large Telescopes. It is expected to be ten times more powerful than the Hubble Telescope, which will allow us to see further into deep space with ultra-sharp clarity. The GMT will be located in the same area as the Magellan Telescope, in Las Campanas Observatory near La Serena, Chile. This area is ideal for space watching because it is one of the least light polluted areas on Earth.

Construction for the GMT was started in November of 2015 and full completion of the telescope is expected to be around 2025. When completed, it will be the largest optical observatory in the world. The GMT will be at an altitude of 8,500 feet and it will consist of seven primary mirrors. Operation for the GMT will begin with just four mirrors in 2022, known as “first light”.

One of the reasons why it will be able to peer deeper into space it due to extra large aperture, which will much bigger than most of the telescopes in existence today.

Comparison_optical_telescope_primary_mirrors-
Comparison of apertures of existing telescope primary mirrors

This powerful telescope will work by using light from the edge of the universe that will first reflect off of the seven primary mirrors, then reflect again off of the seven smaller secondary mirrors, and finally, down through the center primary mirror to the advanced Charge Coupled Device imaging cameras. In the CCD, concentrated light will be measured to determine what objects are made of and how far away they are. The telescope will also explore the origins of chemical elements that make up our planets. The GMT will search distant exoplanets for signs of life around other nearby stars in our Milky Way galaxy. This $1 billion project is US-led in partnership with Australia, Brazil, Korea, and Chile.

Interesting Facts on Astronomy and the Universe