Category The Universe, Exploring the Universe, Solar System, The Moon, Space, Space Travel

Is there an ocean inside the Earth?

Earth is not just a solid ball. It’s interior, as much as its exterior, is a subject of great fascination. You must be aware that Earth’s interior has three major layers: the crust, the mantle, and the core. But did you know there is a vast reservoir of water, three times the volume of all the oceans, deep in the Earth’s mantle?

It is hidden inside a blue rock called ringwoodite and lies 700 km underground in an area called the transition zone in the mantle, the layer of hot rock between the crust and core. Ringwoodite is a rare mineral that forms under very high pressure and temperature, such as those present in the mantle’s transition zone.

The reservoir was discovered in 2014 and it threw new light on the origin of Earth’s water. All along, geologists had thought water came from icy comets as they struck the planet during its formation. But the discovery supports an alternative idea that the oceans came from within the interior of early Earth.

The hidden water could also act as a buffer for the oceans on the surface, explaining why they have stayed the same size for millions of years.

 

Picture Credit : Google

What does we are all stardust mean?

The human body is made up of four fundamental elements: carbon, hydrogen, oxygen and nitrogen (also called the CHON or HONC elements). So are rocks, plants, animals, water and air. Do you know where these elements came from? The STARS. Yes, even the calcium in your bone and iron in your blood came from the distant stars. In fact, every atom in your body was forged in the centre of stars years ago. Read on to know how…

When the universe began 13 or 14 billion years ago, with the Big Bang, the only elements that existed were hydrogen, helium and a small amount of lithium. Over time, gravity increasingly pulled gas molecules towards each other and eventually gave birth to the first generation of stars. These stars were much greater than our Sun in size and temperature. The nuclear fusion within those stars then produced heavier elements, including carbon, oxygen, and nitrogen. When the stars exploded in supernova at the end of their life-cycle, the elements were shot into the far-flung reaches of the universe. Those stellar explosions continued, making new stars and planets. As more, massive stars exploded heavier elements continued to be created. Stars and elements are still being born this way, even as you read this.

As far as our galaxy, Milky Way, is concerned, stars had generated most elements now present on Earth about 5 billion years ago. Within the next billion years, the first signs of life on Earth appeared. No one is exactly sure how life formed on the planet. But one thing is clear like Carl Sagan said. “The cosmos is also within us, we’re made of star stuff.

 

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NASA lifts off cargo spacecraft named after Kalpana Chawla to International Space Station

A commercial cargo spacecraft bound for the International Space Station (ISS) has been named after NASA astronaut, Kalpana Chawla, the first India-born woman to enter space. Northrop Grumman, an American aerospace and defence technology company, announced that its next Cygnus capsule will be named the “S.S. Kalpana Chawla”, in memory of the mission specialist who died with her six crewmates aboard the space shuttle Columbia in 2003. “Chawla’s final research conducted onboard Columbia helped us understand astronaut health and safety during spaceflight. Northrop Grumman is proud to celebrate the life of Kalpana Chawla and her dream of flying through the air and in space,” the company said.

Born in Haryana, India, Chawla moved to the United States to earn her master’s and doctorate degrees in aerospace engineering from the University of Texas in 1984 and the University of Colorado in 1988, respectively.

She then began her career at NASA, conducting research in fluid dynamics at the Ames Research Center in California. After becoming a naturalized US citizen, Chawla applied for and became a NASA astronaut as a member of “The Flying Escargot,” NASA`s 15th class of trainees.

 

Picture Credit : Google

How did scientists estimate Sun’s age?

The Sun’s age

Scientists say our Sun is four-and-a-half billion years old but how did they estimate its age?

To predict the age of the Sun, scientists looked at the age of the whole solar system because it all came together around the same time.

To find out the solar system’s age, scientists looked for the oldest things they could find. And, Moon rocks, meteorites and Earth rocks worked perfectly well for this. Scientists extensively studied these objects, and after much research came to the conclusion that each of the objects were approximately four and- A-half billion years old, and hence, the Sun is likely to be of the same age.

How long will it shine?

Now that we know how old the Sun is, how much longer will it shine upon us?

Scientists believe that stars such as our Sun usually burn for about nine or 10 billion years. This means our Sun is halfway through its life and will last for another five billion years at least.

Once five billion years are up, the Sun will become a red giant. The Sun will become bigger and cooler at the same time and it will be a lot different than the Sun we know today. As a red giant our Sun will become 2,000 times brighter than it is now. Wonder what would happen to our solar system at that time – will there be new life?

 

Picture Credit : Google

If fire needs oxygen, where does the sun get oxygen if there’s no oxygen in space?

Indeed, this was a scientific problem for hundreds of years: if Sun consisted of oxygen, it would run out of fuel in a few hundred years. So what’s the deal?

But wait, nowadays we know more. What other objects glow like the Sun, even without oxygen?

This example of a lamp bulb shows that not all objects that shed light need oxygen to do so. Of course, for light bulb that gas is typically some inert gas (see e.g. Which gas is typically used in light bulb?).

In fact, the light bulb doesn’t use up the gas. Instead, it uses an electric wire, i.e. a resistor, heated up by the electricity flowing through it. The wire heats up, in turn heating up the gas.

The Sun is a bit similar to a light bulb. From early spectroscopic studies in the 1800s, we know that it consists of gas, mostly hydrogen and helium. The latter was actually first discovered on Sun giving the element its name from Helios, Greek name for Sun.

Nowadays we also know that this gas is heated up not by directly burning its chemical constituents, but by a special phenomenon that is the reverse of what’s happening in nuclear power plants: nuclear fusion.

While in nuclear power plants uranium splits up and by doing so releases energy (nuclear fission), in nuclear fusion the hydrogen atoms combine to form helium or even more massive particles. In case of light particles like hydrogen this again releases large amounts of energy.

The energy released speeds up the particles in the Sun’s core and in turn these super-heated particles slowly bounce around and raise to Sun’s surface. There, the temperature of the hydrogen-helium gas is 5500 degrees Celsius or near 10 000 degrees Fahrenheit.

A gas this hot will glow literally like the Sun, finally releasing the heated energy to the universe and, consequentially, to us.

Sun continually loses a tiny portion of its mass to keep shining, combining hydrogen to helium in its fusion forge, its core. From observing other stars like it, we know it has enough nuclear fuel to shine for another few billions of years.

 

Credit : Quora

Picture Credit : Google

What is analemma?

This is what the sun looks like when you take a picture a week, for a year, always at the same time of the day, and in the same place.

Due to the 23.5° inclination of earth’s axis and the ellipticity of its orbit, the height of the sun is not the same every day, and the combined effects is what the image shows.

The height of the points corresponds to the declination of the sun on that date, while the horizontal coordinate indicates the deviation of the solar position with respect to the average time (shown by clocks).

The inclination of the figure depends on the latitude in which it is observed and on the time.

If earth’s orbit were a perfect circle and its axis were perpendicular to the orbit, the sun would be in the same spot every day and the analemma would be a point. With a circular orbit but an inclined axis, the two parts of the analemma would be symmetrical. If the axis were not inclined but the orbit were elliptical, the analemma would instead be a segment.

On other planets the analemma has a different shape, on Mars for example, it looks like a drop.

 

Credit : Quora

Picture Credit : Google