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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.

 

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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?

 

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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

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An asteroid impact is believed to have contributed to the extinction of the dinosaurs. When did this happen?

The dinosaur-killing crash threw huge amounts of debris into the air and caused massive tidal waves to wash over parts of the American continents. There is also evidence of substantial fires from that point in history.

For a long time it was thought that the non-bird dinosaurs died out 65 million years ago.

But Paul explains, ‘The dating of those layers of clay around the world is very accurate – it’s estimated to within a couple of thousands of years.

As originally proposed in 1980 by a team of scientists led by Luis Alvarez and his son Walter, it is now generally thought that the K–Pg extinction was caused by the impact of a massive comet or asteroid 10 to 15 km (6 to 9 mi) wide, 66 million years ago, which devastated the global environment, mainly through a lingering impact winter which halted photosynthesis in plants and plankton.

The blame can’t solely rest on the asteroid. Prior to its crash landing, Earth was experiencing a period of climate change. This was making things harder for life on our planet.

In what is now central India, there was substantial volcanic activity that, although unrelated to the asteroid impact, was causing problems of its own. The resulting lava outcrop is now known as the Deccan Traps.

Paul says, ‘For two million years there was a huge amount of volcanic activity going on, spewing gases into the atmosphere and having a major impact on global climate.

 

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How heavy objects sent to space?

Every year the world sends satellites and spacecraft to space to improve communications on Earth or to explore planets and moons. But how are these heavy objects sent to space?

A rocket ride

We launch things into space by putting them onto rockets that carry tonnes of propellants (fuel). These propellants give the rocket enough energy to boost away from Earth’s surface. Because of Earth’s gravitational pull the heaviest and the largest satellites or spacecraft need the biggest of rockets with most propellant.

Action and reaction

We now know that we need a rocket to send objects to space, but how does a rocket lift off? The most important idea behind a rocket’s lift off is Issac Newton’s over 300-year-old law, which states that for every action there is an equal and opposite reaction.

If you have seen photos and videos of a rocket launch, you would not have missed seeing exhaust streaming from the bottom of the rocket. This exhaust is the flames, hot gases and smoke that come from burning the rockets propellants. This exhaust pushes out from a rocket’s engine down toward the ground. This is the action force. In response to this action, the rocket begins moving in the opposite direction, lifting off the ground. This is the reaction force.

Let’s keep moving

While the rocket will lift off due to the reactive force of the exhaust, Earth’s gravity will continue pulling it down. So how does the rocket continue moving upwards? When a rocket bums propellants and pushes out exhaust an upward force called thrust is created. To launch, the rocket needs enough propellants to create thrust that is greater than the force of the gravity pulling the rocket down. A rocket needs to speed up to at least 29,000 km/hr and fly above most of the atmosphere in a curved path around Earth. This will ensure that the gravity will not pull it back down.

 

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Which was the first animal launched into space?

The Soviet Union stunned the world on Nov. 3, 1957, with the launch of Sputnik 2. On board the small satellite was a little dog, Laika, the first animal to orbit Earth. However, Laika was not the first animal in space. The United States and the U.S.S.R. had been putting animals atop rockets since 1947.

Laika was a young, mostly-Siberian husky. She was rescued from the streets of Moscow. Soviet scientists assumed that a stray dog would have already learned to endure harsh conditions of hunger and cold temperatures. Laika and two other dogs were trained for space travel by being kept in small cages and learning to eat a nutritious gel that would be their food in space.

The dog’s name was originally Kudryavka, or Little Curly, but she became known internationally as Laika, a Russian word for several breeds of dog similar to a husky. American reporters dubbed her Muttnik as a pun on Sputnik.

Unfortunately, Laika’s trip into space was one-way only. A re-entry strategy could not be worked out in time for the launch. It is unknown exactly how long Laika lived in orbit — perhaps a few hours or a few days — until the power to her life-support system gave out. Sputnik 2 burned up in the upper atmosphere in April 1958.

 

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Who are three recipients of Nobel Prize for Physics in recognition of pioneering work?

The Nobel Prize in Physics was awarded to three astrophysicists Tuesday for work that was literally out of the world, and indeed the universe. They are Roger Penrose, an Englishman, Reinhard Genzel, a German, and Andrea Ghez, an American. They were recognized for their work on the gateways to eternity known as black holes, massive objects that swallow light and everything else forever that falls in their unsparing maws.

Black holes were one of the first and most extreme predictions of Einstein’s General Theory of Relativity, first announced in November 1915. The theory explains the force we call gravity, as objects try to follow a straight line through a universe whose geometry is warped by matter and energy. As a result, planets as well as light beams follow curving paths, like balls going around a roulette wheel.

Einstein was taken aback a few months later when Karl Schwarzschild, a German astronomer, pointed out that the equations contained an apocalyptic prediction: In effect, cramming too much matter and energy inside too small a space would cause space-time to collapse into a point of infinite density called a singularity. In that place — if you could call it a place — neither Einstein’s equations nor any other physical law made sense.

Einstein could not fault the math, but he figured that in real life, nature would find a way to avoid such a calamity.

 

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How many moons does Pluto have?

It is intriguing that such a small planet can have such a complex collection of satellites. The discovery provides additional clues for unraveling how the Pluto system formed and evolved.

Pluto’s entire moon system is believed to have formed by a collision between two the dwarf planet and another Kuiper Belt Object early in the history of the solar system. The smashup flung material that coalesced into the family of satellites observed around Pluto.

“The moons form a series of neatly nested orbits, a bit like Russian dolls,” said Mark Showalter of the SETI Institute.

The known moons of Pluto are:

  • Charon: Discovered in 1978, this small moon is almost half the size of Pluto. It is so big Pluto and Charon are sometimes referred to as a double planet system.
  • Nix and Hydra: These small moons were found in 2005 by a Hubble Space Telescope team studying the Pluto system.
  • Kerberos: Discovered in 2011, this tiny moon is located between the orbits of Nix and Hydra.
  • Styx: Discovered in 2012, this little moon was found by a team of scientists searching for potential hazards to the New Horizons spacecraft Pluto flyby in July 2015.
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Which dwarf planet is believed to have harboured a global subsurface ocean that likely froze long ago?

Remnants of an ancient water ocean are buried beneath the icy crust of dwarf planet Ceres — or, at least, lingering pockets of one. That’s the tantalizing find presented August 10 by scientists working on NASA’s Dawn mission. 

By far, Ceres is the largest object in the asteroid belt, which girdles the inner planets between Mars and Jupiter. But unlike its rockier neighbors, Ceres is a giant ice ball. It holds more water than any world in the inner solar except for Earth. That knowledge had long led some astronomers to suspect Ceres may have once had a subsurface ocean, which is part of the reason NASA sent the Dawn spacecraft there.

Ceres is the only dwarf planet in the inner solar system, and it locks up one-third of the entire mass in the asteroid belt. Astronomers think Ceres is a protoplanet, the fossilized remains of a world that never fully formed. But its growth was halted before it could become a full planet. Having such a history means Ceres likely holds an early record of our solar system’s primordial past — hence the name Dawn.

 

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Which are the four planets that are collectively known as plutoids?

According to International Astronomical Union (IAU), which began meeting in August of 2006, the term Plutoid now applies to Pluto, as well as any other small stellar body that exist beyond the range of Neptune.

Pluto was to these stellar objects what Ceres was to large objects in the asteroid belt – that is to say, comparable in size. Astronomers proposed several names for these objects, but matters did not come to a head until Eris was discovered. This dwarf planet was actually larger than Pluto, 2500 km in diameter, making it twenty-seven percent larger than Pluto.

In the end, the IAU could only resolve this matter by removing Pluto from the list of planets and devising a new category for dwarf planets that could no longer be considered true planets. Plutoid was the result, and now applies to the trans-Neptunian objects of Pluto, Haumea, Makemake, and Eris.

 

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