Here We Discuss Different Science Related Stuffs... Chapters & Contains. Innovations in Science world And Some Knowledge Stuff ... Come And See & Let Us Know How You Feel

Water Vapour on the Habitable-Zone Exoplanet K2-18b



Astronomers have finally uncovered water vapour in the atmosphere of a super-Earth exoplanet orbiting within the habitable zone of its star. The find means that liquid water could also exist on the rocky world's surface, potentially even forming a global ocean.

The discovery, made with NASA's Hubble Space Telescope, serves as the first detection of water vapour in the atmosphere of such a planet. And because the planet, dubbed K2-18 b, likely sports a temperature similar to Earth, the newfound water vapour makes the world one of the most promising candidates for follow-up studies with next-generation space telescopes.



Planet K2-18 b sits some 110 light-years away in the constellation Leo, and it orbits a rather small red dwarf star that's roughly one-third the mass of our own Sun. Red dwarfs are infamous for being active stars that emit powerful flares, but the researchers point out that this particular star appears to be surprisingly docile.

This bodes well for the water-bearing planet, as its 33-day orbit brings it about twice as close to its star as Mercury is to the Sun. Given that the star is much cooler than the Sun, in the end, the planet is receiving similar radiation to the Earth. And based on calculations, the temperature of the planet is also similar to the temperature of the Earth.



Specifically, the paper suggests K2-18 b has a temperature between about –100 °F (–73 °C) and 116 °F (47 °C). For reference, temperatures on Earth can span from below –120 °F (–84 °C) in regions like Antarctica to above 120 °F (49 °C) in regions like Africa, Australia, and the Southwestern United States.

Although K2-18 b flaunts some of the most Earth-like features observed in an exoplanet so far — water, habitable temperatures, and a rocky surface — the researchers point out the world is still far from Earth-like. First off, K2-18 b is roughly twice the diameter of Earth, which makes it about eight times as massive. This puts K2-18 b near the upper limit of what we call a super-Earth — which typically refers to planets between about one and 10 Earth masses.



But the density of K2-18 b is what really cements it as a rocky planet. With a density about twice that of Neptune, K2-18 b has a composition most similar to Mars or the Moon. So, because the planet is believed to have a solid surface, and it's known to have an extended atmosphere with at least some water vapour, researchers say it's feasible that K2-18 b could actually be a water world with a global ocean covering its entire surface.

However, they cannot say for sure. The uncertainty is because Hubble can't probe the atmospheres of distant exoplanets in great detail. For instance, thanks to a sophisticated algorithm, the researchers were able to tease out the undeniable signal of water vapour in the atmosphere of K2-18 b, But they couldn't tell exactly how much water vapour is really there. So, in their paper, they took the conservative approach and gave a broad-range estimate for the abundance of water — somewhere between 0.01% and 50%.



In order to pin down exactly how much water is really on K2-18 b, the researchers say we'll have to wait for the next generation of advanced space telescopes to come online. Specifically, NASA's James Webb Space Telescope, scheduled for launch in 2021, and the European Space Agency's Atmospheric Remote-sensing Infrared Exoplanet Large survey (ARIEL) telescope, planned for launch in the late 2020s, are perfectly suited for the challenge.

The new research was published September 11 in Nature Astronomy
Share:

It Rains on the Sun, But When And How?



Rain comes in various forms throughout the solar system water on Earth, methane/ethane on Titan and sulfuric acid on Venus. But did you know it also rains on the sun? Huge drops of plasma in the sun’s outer atmosphere, the corona, onto the scorching surface. 

Mason, a graduate student at The Catholic University of America, was searching for coronal rain: giant globs of plasma, or electrified gas, that drip from the Sun’s outer atmosphere back to its surface. But she expected to find it in helmet streamers, the million-mile tall magnetic loops — named for their resemblance to a knight’s pointy helmet — that can be seen protruding from the Sun during a solar eclipse. Computer simulations predicted the coronal rain could be found there. Observations of the solar wind, the gas escaping from the Sun and out into space, hinted that the rain might be happening.



But she was looking at the wrong place, So where was it?  Instead of the helmet streamers, the rain was found in a smaller kind of magnetic loop on the sun. It was there, just not in the place that the researchers had expected to find it. 

This research might help scientists to answer two mysteries why the sun's outer atmosphere is so much hotter than the star's surface and the source of the slow solar wind. The new data, collected using high-resolution telescopes mounted on NASA's Solar Dynamics Observatory, showed that coronal rain works similarly to rain on Earth — with a few exceptions.  



On Earth, rain is just one part of the larger water cycle, an endless tug-of-war between the push of heat and pull of gravity. In Earth’s hydrological cycle, water evaporates on the surface and rises up into the atmosphere. It then cools and condenses into clouds, and when there is enough moisture in the clouds, it falls back to the surface as rain. Coronal rain is a somewhat similar process, but with a completely different composition of the rain itself.

On the Sun coronal rain works similarly, but instead of 60-degree water you are dealing with a million-degree plasma.  Plasma, an electrically-charged gas, doesn’t pool-like water, but instead traces the magnetic loops that emerge from the Sun’s surface like a rollercoaster on tracks. At the loop’s foot points, where it attaches to the Sun’s surface, the plasma is superheated from a few thousand to over 1.8 million degrees Fahrenheit. It then expands up the loop and gathers at its peak, far from the heat source. As the plasma cools, it condenses and gravity lures it down the loop’s legs as coronal rain.



In previous theories, it was thought that coronal rain only occurred in closed loops, where the plasma heats and cools, but can’t escape into space. Mason’s work suggests, however, that the rain begins in a closed-loop, but then switches – through a process called magnetic reconnection – to an open one, like a train switching tracks. Some of the plasma will then escape, but some will fall back to the surface as rain. The plasma that does escape forms part of the slow solar wind.

How and why the Sun’s outer atmosphere is some 300 times hotter than its surface might have a strange connection to the plasma rain.  Simulations have shown that coronal rain only forms when the heat is applied to the very bottom of the loop. On the face of it, that observed fact doesn’t seem to make logical sense. As Mason found, the rain in the loops can provide a cutoff point to determine just where the corona is getting heated: If a loop has coronal rain on it, that means that the bottom 10% of it or less, is where coronal heating is happening.



Bottom line is Rain on the sun may sound nonsensical, but it is real and may help to solve some long-lingering puzzles about how our sun works. The researchers plan to study the smaller magnetic loop structures further using NASA's Parker Solar Probe, which launched in 2018 and has already travelled closer to the sun than any other spacecraft. 
Share:

Is It Possible To Terraform Mars To Support Life As We Know It?



Science fiction writers have long featured terraforming, the process of creating an Earth-like or habitable environment on another planet, in their stories. Scientists themselves have proposed terraforming to enable the long-term colonization of Mars. A solution common to both groups is to release carbon dioxide gas trapped in the Martian surface to thicken the atmosphere and act as a blanket to warm the planet.

However, Mars does not retain enough carbon dioxide that could practically be put back into the atmosphere to warm Mars, according to a new NASA-sponsored study.  Transforming the inhospitable Martian environment into a place astronauts could explore without life support is not possible without technology well beyond today’s capabilities.

Although the current Martian atmosphere itself consists mostly of carbon dioxide, it is far too thin and cold to support liquid water, an essential ingredient for life. On Mars, the pressure of the atmosphere is less than 1% of the pressure of Earth’s atmosphere. Any liquid water on the surface would very quickly evaporate or freeze.

Proponents of terraforming Mars propose releasing gases from a variety of sources on the Red Planet to thicken the atmosphere and increase the temperature to the point where liquid water is stable on the surface. These gases are called “greenhouse gases” for their ability to trap heat and warm the climate. Carbon dioxide (CO2) and water vapour (H2O) are the only greenhouse gases that are likely to be present on Mars in sufficient abundance to provide any significant greenhouse warming.

Although studies investigating the possibility of terraforming Mars have been made before, the new result takes advantage of about 20 years of additional spacecraft observations of Mars. The researchers analyzed the abundance of carbon-bearing minerals and the occurrence of CO2 in polar ice using data from NASA’s Mars Reconnaissance Orbiter and Mars Odyssey spacecraft, and used data on the loss of the Martian atmosphere to space by NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft.

The results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming. We don't have the technology to be put desire quantity of greenhouse gases into the atmosphere yet, in addition, most of the CO2 present on Mars is not accessible and could not be readily mobilized.

Although Mars has significant quantities of water ice that could be used to create water vapour, previous analyses show that water cannot provide significant warming by itself; temperatures do not allow enough water to persist as vapour without first having significant warming by CO2, according to the team. Also, while other gases such as the introduction of chloroflorocarbons or other fluorine-based compounds have been proposed to raise the atmospheric temperature, these gases are short-lived and would require large-scale manufacturing processes, so they were not considered in this study.

The atmospheric pressure on Mars is around 0.6% of Earth’s. With Mars being further away from the Sun, researchers estimate a CO2 pressure similar to Earth’s total atmospheric pressure is needed to raise temperatures enough to allow for stable liquid water. The most accessible source is CO2 in the polar ice caps; it could be vaporized by spreading dust on it to absorb more solar radiation or by using explosives. However, vaporizing the ice caps would only contribute enough CO2 to double the Martian pressure to 1.2% of Earth’s, according to the new analysis.

Another source is CO2 attached to dust particles in Martian soil, which could be heated to release the gas. The researchers estimate that heating the soil could provide up to 4% of the needed pressure. A third source is carbon locked in mineral deposits. Using the recent NASA spacecraft observations of mineral deposits, the team estimates the most plausible amount will yield less than 5% of the required pressure, depending on how extensive deposits buried close to the surface may be. Just using the deposits near the surface would require extensive strip mining, and going after all the CO2 attached to dust particles would require strip mining the entire planet to a depth of around 100 yards. Even CO2 trapped in water-ice molecule structures, should such “clathrates” exist on Mars, would likely contribute less than 5% of the required pressure, according to the team.

Carbon-bearing minerals buried deep in the Martian crust might hold enough CO2 to reach the required pressure, but the extent of these deep deposits is unknown, not evidenced by orbital data, and recovering them with current technology is extremely energy-intensive, requiring temperatures above 300 degrees Celsius (over 572 degrees Fahrenheit). Shallow carbon-bearing minerals are not sufficiently abundant to contribute significantly to greenhouse warming, and also require the same intense processing.

Although the surface of Mars is inhospitable to known forms of life today, features that resemble dry riverbeds and mineral deposits that only form in the presence of liquid water provide evidence that, in the distant past, the Martian climate supported liquid water at the surface. But solar radiation and solar wind can remove both water vapor and CO2 from the Martian atmosphere.

Both MAVEN and the European Space Agency’s Mars Express missions indicate that the majority of Mars’ ancient, potentially habitable atmosphere has been lost to space, stripped away by solar wind and radiation. Of course, once this happens, that water and CO2 are gone forever. Even if this loss were prevented somehow, allowing the atmosphere to build up slowly from outgassing by geologic activity, current outgassing is extremely low; it would take about 10 million years just to double Mars’ current atmosphere, according to the team.

Answer to the question is yes it is possible to Terraform Mars to support Life as we know it. But with currently available technology we can't do it.
Share:

How Does Solar Sail Work?



Solar sails are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large mirrors. These particles of light have no mass and yet when they impinge on something, they can impart momentum and provide a tiny push. You get shoved by photons every time you step out into the sunshine but their incredibly small force is essentially unnoticeable to your body. 

In space, things take a different turn. The laws of physics state that every action must have an equal and opposite reaction, so, when photons from the sun bounce off a spaceship, the ship is propelled ever so slightly in a direction away from the sun. With a single photon, the change is negligible but a large collection of them can provide significant thrust. 



Place a large, flat, mirror-like sheet in front of a spacecraft and the sun's power will push it forward. The material must also be strong and gossamer-thin in order to catch and control the sunlight. Solar sails can tack like regular sails to travel in many directions, according to the Planetary Society. The technology has an advantage over other propulsion methods because a ship does not need to carry fuel wherever it goes, instead, relying on the freely-available light of stars. 

Since they get a continuous push from the sun, solar-sail-powered ships can constantly accelerate as they journey to the edge of the solar system, achieving super-fast speeds that would be much more difficult for chemical rockets. Alternatively, solar sails can also be driven by gargantuan laser beams.



NASA tested the concept of solar sailing in 1974 with its Mariner 10 spacecraft, which was designed to fly past Venus and Mercury. When the probe ran out of fuel, mission control turned its solar panels to just the right angle to catch the sun's rays and push the spacecraft forward. 

The first human-made solar sail to successfully fly was the Japanese Space Exploration Agency's Interplanetary Kite-craft Accelerated by Radiation Of the Sun (IKAROS) spacecraft. The robot deployed its 46-foot-wide (14 meters) sail in June 2010 and proved the ability to control its direction and change orientation on command. 



That same year, NASA launched the tiny NanoSail-D demonstrator mission, which had a diamond-shaped sail 10 feet (3 m) to a side. The probe unfurled its solar sail in 2011 and circled the Earth for eight months before burning up in the atmosphere. Lightweight and with little room to carry fuel, small satellites are thought to be ideal candidates for this type of propulsion. 

In 2015, the Planetary Society launched the LightSail-1 spacecraft into orbit, which sported a 344-square-foot (32-square-m) solar sail, about the size of a boxing ring. Despite some successes, and a selfie or two, the mission suffered from technical glitches and eventually stopped transmitting signals before entering the atmosphere a few weeks after it was launched. 



But the Planetary Society is back at it and has high hopes for their new LightSail-2 mission. The craft is about the size of a bread loaf and intends to release a similarly-sized sail as its predecessor. Mission planners said that one-day solar-sail-driven ships could travel to the edge of the solar system or beyond. 

The Breakthrough Starshot Initiative intends to do just that, sending lightweight microchip-sized probes to explore the nearest star system, Alpha Centauri, which is 4.3 light-years away. Announced in 2016, the $100-million venture is investigating the feasibility of using a colossal Earth-based laser to accelerate the chips to 20% the speed of light and reaching Alpha Centauri in only 20 years. 




Share:

NASA’s James Webb Space Telescope



Reaching a major milestone, engineers have successfully connected the two halves of NASA’s James Webb Space Telescope for the first time at Northrop Grumman’s facilities in Redondo Beach, California. Once it reaches space, NASA's most powerful and complex space telescope will explore the cosmos using infrared light, from planets and moons within our solar system to the most ancient and distant galaxies.

To combine both halves of Webb, engineers carefully lifted the Webb telescope (which includes the mirrors and science instruments) above the already-combined sun shield and spacecraft using a crane. Team members slowly guided the telescope into place, ensuring that all primary points of contact were perfectly aligned and seated properly. The observatory has been mechanically connected; the next steps will be to electrically connect the halves and then test the electrical connections. 



“The assembly of the telescope and its scientific instruments, sun shield and the spacecraft into one observatory represents an incredible achievement by the entire Webb team,” said Bill Ochs, Webb project manager for NASA Goddard Space Flight Center in Greenbelt, Maryland.  “This milestone symbolizes the efforts of thousands of dedicated individuals for over more than 20 years across NASA, the European Space Agency, the Canadian Space Agency, Northrop Grumman, and the rest of our industrial and academic partners.”

Next up for Webb testing, engineers will fully deploy the intricate five-layer sun shield, which is designed to keep Webb's mirrors and scientific instruments cold by blocking infrared light from the Earth, Moon and Sun. The ability of the sunshield to deploy to its correct shape is critical to mission success.



“This is an exciting time to now see all Webb’s parts finally joined together into a single observatory for the very first time,” said Gregory Robinson, the Webb program director at NASA Headquarters. “The engineering team has accomplished a huge step forward and soon we will be able to see incredible new views of our amazing universe.”

Both of the telescope’s major components have been tested individually through all of the environments they would encounter during a rocket ride and orbiting mission a million miles away from Earth. Now that Webb is a fully assembled observatory, it will go through additional environmental and deployment testing to ensure mission success. The spacecraft is scheduled to launch in 2021.



Webb will be the world's premier space science observatory. It will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

The James Webb Space Telescope (sometimes called JWST or Webb) will be a large infrared telescope with a 6.5-meter primary mirror.  The telescope will be launched on an Ariane 5 rocket from French Guiana in 2021.



Webb will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

Several innovative technologies have been developed for Webb. These include a primary mirror made of 18 separate segments that unfold and adjust to shape after launch. The mirrors are made of ultra-lightweight beryllium. Webb’s biggest feature is a tennis court-sized five-layer sunshield that attenuates heat from the Sun more than a million times. The telescope’s four instruments - cameras and spectrometers - have detectors that are able to record extremely faint signals. One instrument (NIRSpec) has programmable micro shutters, which enable observation up to 100 objects simultaneously. Webb also has a cryocooler for cooling the mid-infrared detectors of another instrument (MIRI) to a very cold 7 K so they can work.



Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.
Share:

Why Does Earth's Magnetic Field Flip?



Earth's magnetic field has flipped many times over the last billion years, according to the geologic record. But only in the past decade have scientists developed and evolved a computer model to demonstrate how these reversals occur.

Based on a set of physics equations that describe what scientists believe are the forces that create and maintain the magnetic field, Glatzmaier and colleague Paul Roberts at the University of California, Los Angeles, created a computer model to simulate the conditions in the Earth's interior.



The computer-generated magnetic field even reverses itself, allowing scientists to examine the process. Scientists believe Earth's magnetic field is generated deep inside our planet. There, the heat of the Earth's solid inner core churns a liquid outer core composed of iron and nickel. The churning acts like convection, which generates electric currents and, as a result, a magnetic field.

This magnetic field shields most of the habited parts of our planet from charged particles that emanate from space, mainly from the sun. The field deflects the speeding particles toward Earth's Poles.



Our planet's magnetic field reverses about once every 200,000 years on average. However, the time between reversals is highly variable. The last time Earth's magnetic field flipped was 780,000 years ago, according to the geologic record of Earth's polarity.

The information is captured when molten lava erupts onto Earth's crust and hardens, much in the way that iron filings on a piece of cardboard align themselves to the field of a magnet held beneath it.



Most scientists believe our planet's magnetic field is sustained by what's known as the geodynamo. The term describes the theoretical phenomenon believed to generate and maintain Earth's magnetic field. However, there is no way to peer 4,000 miles (6,400 kilometres) into Earth's centre to observe the process in action.

That inability spurred Glatzmaier and Roberts to develop their computer model in 1995. Since then, they have continued to refine and evolve the model using ever more sophisticated and faster computers.



The model is essentially a set of equations that describe the physics of the geodynamo. The equations are continually solved, each solution advancing the clock forward about a week. At its longest stretch, the model ran the equivalent of 500,000 years, Glatzmaier said.

By studying the model, the scientists discovered that, as the geodynamo generates new magnetic fields, the new fields usually line up in the direction of the existing magnetic field. But once in a while a disturbance will twist the magnetic field in a different direction and induce a little bit of a pole reversal.



These bits of a pole reversal are referred to as instabilities. They constantly occur in the fluid flow of the core, tracking through it like little hurricanes, though at a much slower pace—about one degree of latitude per year.

Typically, instabilities are temporary. But on very rare occasions, conditions are favourable enough that the reversed polarity gets bigger and bigger as the original polarity decays. If this new polarity takes over the entire core, it causes a pole reversal.



Peter Olson, a geophysicist at Johns Hopkins University in Baltimore, Maryland, said scientists can now pinpoint the core-mantle boundary where these instabilities in the magnetic field are happening.

One such disturbance Olson has been observing recently formed over the east-central Atlantic Ocean. Like a little hurricane, the anomaly swept toward the Caribbean and is moving up in the direction of North America.



Instabilities such as this are causing Earth's magnetic field to weaken. Today the field is about 10% weaker than it was when German mathematician Carl Friedrich Gauss first began measuring it in 1845. Some scientists speculate the field is headed for a reversal.
Share:

Magnetic North Is Shifting Fast. But Why?



Like most planets in our solar system, the Earth has its own magnetic field. Thanks to its largely molten iron core, our planet is, in fact, a bit like a bar magnet. It has a north and south magnetic pole, separate from the geographic poles, with a field connecting the two. This field protects our planet from radiation and is responsible for creating the northern and southern lights – spectacular events that are only visible near the magnetic poles.



Our planetary magnetic field has many advantages. For over 2,000 years, travellers have been able to use it to navigate across the globe. Some animals even seem to be able to find their way thanks to the magnetic field. But, more importantly than that, our geomagnetic field helps protect all life on Earth.

Earth’s magnetic field extends hundreds of thousands of kilometres out from the centre of our planet – stretching right out into interplanetary space, forming what scientists call a “magnetosphere”. This magnetosphere helps to deflect solar radiation and cosmic rays, preventing the destruction of our atmosphere. This protective magnetic bubble isn’t perfect though, and some solar matter and energy can transfer into our magnetosphere.



Since Earth’s magnetic field is created by its moving, molten iron core, its poles aren’t stationary and they wander independently of one another. In fact, since its first formal discovery in 1831, the north magnetic pole has travelled over 2,000km from the Boothia Peninsula in the far north of Canada to high in the Arctic Sea. This wandering has generally been quite slow, around 9km a year, allowing scientists to easily keep track of its position. But since the turn of the century, this speed has increased to 50km a year. The south magnetic pole is also moving, though at a much slower rate (10-15km a year).

This rapid wandering of the north magnetic pole has caused some problems for scientists and navigators alike. Computer models of where the north magnetic pole might be in the future have become seriously outdated, making accurate compass-based navigation difficult. Although GPS does work, it can sometimes be unreliable in the polar regions. In fact, the pole is moving so quickly that scientists responsible for mapping the Earth’s magnetic field were recently forced to update their model much earlier than expected.



In the meantime, scientists are working to understand why the magnetic field is changing so dramatically. Geomagnetic pulses, like the one that happened in 2016, might be traced back to ‘hydromagnetic’ waves arising from deep in the core. And the fast motion of the north magnetic pole could be linked to a high-speed jet of liquid iron beneath Canada.

The jet seems to be smearing out and weakening the magnetic field beneath Canada. Which means that Canada is essentially losing a magnetic tug-of-war with Siberia.



The location of the north magnetic pole appears to be governed by two large-scale patches of the magnetic field, one beneath Canada and one beneath Siberia. The Siberian patch is winning the competition. Which means that the world’s geomagnetists will have a lot to keep them busy for the foreseeable future.



Share:

What Is Geothermal Energy?


Geothermal energy is heat derived within the sub-surface of the earth. It is contained in the rocks and fluids beneath the earth’s crust and can be found as far down to the earth’s hot molten rock, magma. Water or steam carry the geothermal energy to the Earth’s surface. Depending on its characteristics, geothermal energy can be used for heating and cooling purposes or be harnessed to generate clean electricity.

This key renewable source covers a significant share of electricity demand in countries like Iceland, El Salvador, New Zealand, Kenya, and the Philippines and more than 90% of heating demand in Iceland. The main advantages are that it is not depending on weather conditions and has very high capacity factors; for these reasons, geothermal power plants are capable of supplying baseload electricity, as well as providing ancillary services for short and long-term flexibility in some cases. It's clean and sustainable.



Many technologies have been developed to take advantage of geothermal energy like 1. Geothermal Electricity Production ( Generating electricity from the earth's heat. ) 2. Geothermal Direct Use ( Producing heat directly from hot water within the earth. ) 3. Geothermal Heat Pumps ( Using the shallow ground to heat and cool buildings. ). 

To produce power from geothermal energy, wells are dug a mile deep into underground reservoirs to access the steam and hot water there, which can then be used to drive turbines connected to electricity generators. There are three types of geothermal power plants; dry steam, flash and binary. 



Dry steam is the oldest form of geothermal technology and takes the steam out of the ground and uses it to directly drive a turbine. Flash plants use high-pressure hot water into cool, low-pressure water whilst binary plants pass hot water through a secondary liquid with a lower boiling point, which turns to vapour to drive the turbine.

However, there are some drawbacks to the energy source. Despite low CO2 production geothermal has been associated with other emissions like sulphur dioxide and hydrogen sulphide. Similar to fracking, geothermal power plants have been the cause of mini tremors in the area they operate in and also has a high initial cost to build. 



It is also described as “the most location-specific energy source known to man” due to its activity being along the tectonic plates of the earth’s crust.  As such, it is limited to countries such as the aforementioned US and Iceland, alongside Kenya and Indonesia.
Share:

Why There’s Less Gravity in Hudson Bay, Canada ?


The Hudson Bay region of Canada has less gravity than it’s supposed to. The reasons for the shortage have puzzled scientists for decades.

Gravity isn’t uniform all over the Earth’s surface. It’s a result of mass, which means the varying density of the Earth at different locations can affect how much you weigh there. Canadians aren’t all free-floating like Sandra Bullock, but the effect is definitely measurable. In the Hudson Bay region, the average resident weighs about a tenth of an ounce less than they would weigh elsewhere.



Researchers have puzzled for years over whether this was due to the crust there rebounding slowly after the end of the last ice age or a deeper issue involving convection in the Earth’s mantle or some combination of the two.

Now, ultra-precise measurements taken over four years by a pair of satellites known as GRACE (Gravity Recovery and Climate Experiment) reveal that each effect is equally responsible for Canada’s low gravity. The work could shed light on how continents form and evolve over time.



The two spacecraft fly 500 kilometres above the Earth, 220 kilometres apart. Using a microwave ranging system, the two spacecraft can measure distance differences between them as tiny as a micron. That allows them to measure tiny changes in the distribution of mass and hence gravity on the Earth. For example, if the leading spacecraft were to encounter an area with more gravity, it would be pulled ever-so-slightly closer to Earth than the trailing spacecraft, and that distance can be measured.

At first, researchers suspected it was due to an ice sheet called Laurentide that blanketed a sizeable chunk of North America during the last ice age. In places, the sheet was more than 3 kilometres thick, and it depressed the Earth’s crust beneath it.



When the ice age ended about 20,000 years ago, the ice rapidly melted. But the crust has been springing back much more slowly, and it is rebounding today by about 12 millimetres per year. But in the last decade or so, scientists have begun to suspect that convection in the Earth’s mantle, a layer of hot, flowing rock beneath the crust, also plays a role.

The sludge-like mantle rises and falls in plumes as it is heated from below and cooled from above. The mantle can drag the overlying tectonic plates with it as it moves. GRACE cannot directly detect that movement since it is so slow. But scientists inferred the gravitational contribution of convection by subtracting the post-glacier effect from the region’s overall gravity signal.



Even after the Earth’s crust rebounds completely from the glacier melting, there may still be a gravitational low over the area due to mantle convection. That would suggest that even parts of a continent away from the tectonic plate boundaries are affected by mantle convection.

In simple word during the last ice age, Canada was covered by a vast glacier called the Laurentide Ice Sheet. This sheet was two miles thick over northern Quebec and stretched as far south as modern-day New York and Chicago.



Ice is heavy, so five million square miles of it pushed down on the rock underneath, squishing it like a Nerf ball. When the ice began to melt, about 21,000 years ago, the Earth began to spring back, but, like a Nerf ball, it takes a while. To this day, the Earth in the Hudson Bay region is still deformed, with lots of rock-mass having been pushed outward by all the ice. Less mass means less gravity.



Share:

Building A Base On The Moon


The cold war between the US and Russia ended half a century ago. But it paved the way for Space exploration for the year to come. On 12 April 1961 Yuri Alekseyevich Gagarin made history by becoming the first human to journey into outer space, achieving a major milestone in the Space Race. Then the Space Race ended when Neil Alden Armstrong became the first to walk on the moon.

Since then no human had set foot on any heavenly body. But now after Elon Musk's BFR announcement and China's successful landing on the far side of the moon another race to make a base on the moon is all set to start. And this time private companies and national space agencies are in it all together to put humans back on the lunar surface. But what we will need before we start building a Base On Moon.



Building a living space out of the Moon’s available resources makes sense. There’s the potential of using lava tubes, tunnels formed during the Moon’s volcanic past, as shelters with access to frozen water ice beneath the surface. But a more immediate plan is to build a habitat using lunar regolith, the fine dark basaltic grey sand that is similar to volcanic sand on Earth.

Building a moon base and actually living on the moon will require careful planning. First, we need to identify and map available lunar resources, including hydrogen and water ice. Such compounds are crucial if we are to create breathable air and rocket fuel, whether for an observatory or a launchpad to go to the outer planets in our solar system.



There are many desirable resources on the moon, from the water ice that can give us fuel and air and other volatile elements to titanium. These may have accumulated in permanently shadowed polar regions, where it is too cold for them to vaporise.

Professor Matthias Sperl from the University of Cologne works with the German Space Agency, DLR, using volcanic powder to make bricks. The regolith simulant is held together using a process called sintering, where concentrated sunlight or lasers bond the material together. He used 3D printers to construct different shaped bricks to see which worked best. “What we can build with current techniques and shapes is interlocking building elements,” said Sperl. “We’re not building Lego but we have interlocking bricks.”



Any moonbase is likely to be situated at the Moon’s poles as evidence of water ice was detected there. Oxygen within the lunar regolith itself could also be extracted for breathing. The most likely source is ilmenite (FeTiO3) which, when combined with hydrogen at temperatures of around 1,000C (1,832F), produces water vapour, which then needs to be separated to produce hydrogen and oxygen. 

So all there is left to do is to go there and build one right? The answer is not so black and white. The Moon has temperatures ranging from 127 to -173 C (260 to -343F). Then there’s radiation and the low gravity, one-sixth that of the Earth’s. A lunar day is also around 29 Earth days, which means two weeks of daylight followed by two weeks of darkness – an issue for solar power. Any new technologies for a lunar outpost must, therefore, work under these conditions.



As well as logistics is a huge challenge as we can't load everything on one single rocket yet. So yes it is within our reach to completely build a base on the Moon, but it will at least take a decade to do so. 



Share:

What is Mars Solar Conjunction ?


Solar conjunction is the period when Earth and Mars, in their eternal march around the Sun, are obscured from each other by the fiery orb of the Sun itself. Like dancers on either side of a huge bonfire, the two planets are temporarily invisible to each other.

During this period the daily communication between antennas here on Earth and those on spacecraft at Mars stops for a few weeks. Sun emits hot, ionized gas from its corona, which stretches out far into space. During solar conjunction, this gas can meddle with radio signals when engineers attempt to speak with spacecraft at Mars, undermining directions and bringing about unforeseen conduct from our deep space explorers.



To be safe, engineers hold off on sending commands when Mars disappears far enough behind the Sun's corona that there's increased risk of radio interference.

Solar conjunction occurs every two years. This year, the solar conjunction moratorium on commanding all Mars spacecraft is between Aug. 28 and Sept. 7, 2019, when Mars is within 2 degrees of the Sun. 



Share:

Turn Daily Plastic Waste Products Into Jet Fuel


For too long, the public conversation around plastic has been narrowly focused on plastic waste in the ocean. While marine debris is indeed a serious part of the problem, this limited focus leaves too much of the story untold. Plastic isn’t just a problem when it enters the environment as waste. Rather, plastic pollutes at every step of its life.

But now all those Plastic trash may help people fly as researchers have found a way to turn daily plastic waste products into jet fuel. Researchers at Washington State University melted plastic waste at high temperature with activated carbon to produce jet fuel.



For the study, the research team tested low-density polyethylene and mixed a variety of waste plastic products like water bottles, milk bottles, plastic bags and ground them down to around three millimetres, or about the size of a grain of rice.

During the research, the plastic granules were then placed on top of activated carbon in a tube reactor at a high temperature, ranging from 430 degree Celsius to 571 degrees Celsius. The carbon is a catalyst or a substance that speeds up a chemical reaction without being consumed by the reaction.



After testing several different catalysts at different temperatures, the best result they had produced a mixture of 85% jet fuel and 15%  diesel fuel, said the study published in the journal Applied Energy.

This new process shows promise in reducing that waste. At least 4.8 million tonnes of plastic enter the ocean each year worldwide, according to conservative estimates by scientists. But now we can almost recover 100% energy of the plastic and convert it into very high-quality fuel. 



Share:

What Is 5G?

The world’s connectivity needs are changing. Global mobile data traffic is expected to multiply by 5 before the end of 2024. Particularly in dense urban areas, the current 4G networks simply won’t be able to keep up.

That’s where a new G comes into play. With 5G commercial networks being switched on, the first use cases are enhanced mobile broadband, which will bring better experiences for smartphone users, and fixed wireless access, providing fibre speeds without fibre to homes. 5G smartphones are already in the market from the beginning of 2019.



Being able to download a full-length HD movie in seconds and share your wow-moments with friends that’s just the beginning. The true value of 5G is the opportunity it presents for people, business and the world at large: industries, regions, towns and cities that are more connected, smarter and more sustainable.

With 5G, data transmitted over wireless broadband connections could travel at rates as high as 20 Gbps as well as offer latency of 1 ms or lower for uses that require real-time feedback. 5G will also enable a sharp increase in the amount of data transmitted over wireless systems due to more available bandwidth and advanced antenna technology.



5G offers network management features, among them network slicing, which allows mobile operators to create multiple virtual networks within a single physical 5G network. This capability will enable wireless network connections to support specific uses or business cases and could be sold on an as a service basis.

A self-driving car, for example, would require a network slice that offers extremely fast, low-latency connections so a vehicle could navigate in real-time. A home appliance, however, could be connected via a lower-power, slower connection because high performance is not crucial. The internet of things (IoT) could use secure, data-only connections.



So, how does 5G technology achieve all these cool features? How 5G works?

Well, Wireless networks are composed of cell sites divided into sectors that send data through radio waves. Fourth-generation (4G) Long-Term Evolution (LTE) wireless technology provides the foundation for 5G. Unlike 4G, which requires large, high-power cell towers to radiate signals over longer distances, 5G wireless signals will be transmitted via large numbers of small cell stations located in places like light poles or building roofs.

The use of multiple small cells is necessary because the millimetre wave spectrum -- the band of spectrum between 30 GHz and 300 GHz that 5G relies on to generate high speeds -- can only travel over short distances and is subject to interference from weather and physical obstacles, like buildings.



The introduction of 5G will make it possible for communications service providers to improve their business in various ways. Just as 4G shook up the landscape, whereby data packages became more important than voice and SMS packages, 5G brings opportunities for communications service providers to offer new services. 5G will also improve cost-efficiency. A study suggests that 5G will enable 10 times lower cost per gigabyte than current 4G networks.

5G fixed wireless broadband services could deliver internet access to homes and businesses without a wired connection to the premises. To do that, network operators deploy NRs(5G New Radio is a new radio access technology (RAT) developed by 3GPP for the 5G (fifth generation) mobile network.) in small cell sites near buildings to beam a signal to a receiver on a rooftop or a windowsill that is amplified within the premises. 



Fixed broadband services are expected to make it less expensive for operators to deliver broadband services to homes and businesses because this approach eliminates the need to roll out fibre-optic lines to every residence. Instead, operators need only install fibre optics to cell sites, and customers receive broadband services through wireless modems located in their residences or businesses.

5G also presents an opportunity for operators to tap into revenue streams emerging from the digitalization of industries. Enabling new use cases, new services new business models and new eco-system which can add up to 36% growth in revenues. 



5G is enabling a new wave of innovation. It has the potential for changing the world, further powering the hottest trends in tech today: IoT (Internet of Things), AI (Artificial Intelligence) and AR (Augmented Reality) – among many more.
Share:

Why do Fevers get Worse at Night?

The illness goes bump in the night may not be just a patient's imagination. Doctors have sensed for centuries that many diseases actually do get worse at night and science has begun to confirm this impression.

Fevers are often worse at night. The same is often said about asthma, arthritis and the flu. And although heart attacks commonly occur in the morning, researchers believe they are frequently triggered by night-time happenings in the body. There is a field of study in biology devoted to understanding how the time of day affects our health called chronobiology.



The symptoms of fever are abnormally high body temperature, shivering and sweating, headache, muscle ache, loss of appetite, and general fatigue. In some cases, children under 5 may suffer seizures during high fever spikes alarming for parents, but not usually life-threatening. 

It’s important to remember that fever itself is not a disease. In fact, it’s the exact opposite a sign that the body’s immune system is fighting off a bacterial or viral infection although it can be a cause for serious concern. Like if an infant less than two months of age is running a fever greater than 100.4 degrees Fahrenheit, or if anyone with a compromised immune system spikes a fever.



There are some fairly obvious explanations for fever symptoms to be magnified during the evening hours.  Just like our sleep schedules, our immune system also has a rest pattern of its own when it is more active and when it is not. Our immunity defends the body differs from day to night. Hence, doctors generally don’t rule out fever before 24-48 hours even if you are feeling completely fine during the day.

During the day, our immune cells protect us but as night approaches, immune cells get less active and do some inflammatory action, by deliberately increasing the body temperature in hopes of killing the bacteria. This phenomenon is called ‘temporary fever’, which fight infections.



It's the body’s defence mechanism ensuring that the entire immune defence force is prepared to put up a fight during the morning since it is the time when most productive things happen. 

There’ is one other element that we don’t quite fully understand, but it seems to be important. We know that two key hormones cortisol and adrenaline are suppressed when we sleep. From extensive studies on asthma management, we have learned that when the level of these hormones is reduced at night, it’s harder for asthmatics to breathe. Researchers believe this restriction also exacerbates fever symptoms at night. 



When you or your family members have a troubling fever, trust your instincts if you think something is wrong, then call your paediatrician or family doctor for advice.
Share:

Two Supermassive Black Holes On A Collision Course

Supermassive black holes are thought to be at the centre of most galaxies, and they are huge. The Milky Way’s own supermassive black hole, Sagittarius A*, is about 4 million times the mass of our sun. But scientists have just spotted two absolute behemoths, that dwarf Sagittarius A*, and they are on a collision course. It’s the first time such massive black holes have been spotted this close together, and it could help us detect a hum of gravitational background noise. 

Of course “close” is a relative term and in this particular instance when scientists say close, they mean about 1,400 light-years apart. The black holes are located about 2.5 billion light-years from us, so since the light from them took 2.5 billion years to reach us, we are observing them as they were 2.5 billion years ago.



Coincidentally, the scientists who discovered them estimate that that’s about how long it will take before they collide. They could be merging with each other right now, unleashing huge gravitational waves millions of times more powerful than those previously detected by LIGO and Virgo. Of course, because of how far away they are, the waves won’t reach us for 2.5 billion years.

That is if they happen at all. We have observed stellar-mass black holes merging, but we are not sure if their supermassive counterparts can join forces by merging too. It seems odd, these things each have an incredible gravitational pull, why wouldn’t they run head-on into each other?



Right now the thinking is when galaxies merge, their supermassive black holes begin to orbit each other. As they do, dust and stars in between them sap some of their energy, causing their orbits to tighten. But as they get closer, that region of space between them shrinks, until theoretically there’s no way to lose more energy.

The two black holes find themselves stably orbiting each other but never getting closer. Some studies suggest that happens at about 1 parsec, or roughly 3.2 light-years distance, so it’s known as the final parsec problem. But all that is theoretical, and we’re lacking more observational data.



It’s possible our predictions are wrong and black holes of this size do merge instead of stalling out a parsec apart. Unfortunately, black hole pairs are very hard to spot. Remember how we mentioned earlier this is the closest we have seen two this big and they’re 1,400 light-years away from each other?

Because 1 parsec is way too close for us to distinguish two supermassive black holes apart. And now that we have found these two, it’s not like we can wait around 2.5 billion years to see if they merge. we will probably be dead by then. But since we have spotted these two, we can start to guess how common merging supermassive black holes would be. 



Based on their findings the scientists estimate that optimistically there are 112 black holes whose gravitational waves we can detect from Earth. This would make a kind of constant hum, the scientists likened this gravitational background noise to a chorus of chirping crickets. 

Normally it’d be impossible to distinguish one cricket from another. But if there’s no final parsec problem and they can merge, it should create a massive chirp at the moment they collide. When that happens, the waves will be at frequencies outside what LIGO and Virgo can detect. So instead, scientists will have to keep a close eye on pulsars, special stars that send out radio waves at regular intervals.



If a supermassive merger stretches or compresses the space between us and a pulsar, the rhythm will appear to be thrown off. These frequency changes are so small, just tens to hundreds of Nanohertz, it will require close to a decade of observation to spot the weak signal hiding in the noise. 

They are searching for more pairs of black holes to refine their prediction further, but it’s possible we never detect a merger and the final parsec problem is insurmountable after all. And while LIGO can’t detect supermassive mergers, it was recently upgraded, making it 40% more sensitive as it continues its hunt for merging stellar-mass black holes.


Source:-  The Astrophysical Journal Letters :- http://bit.ly/2z6YfJx
Share:

Follow by Email

Recent Posts

Water Vapour on the Habitable-Zone Exoplanet K2-18b

Astronomers have finally uncovered water vapour in the atmosphere of a super-Earth exoplanet orbiting within the habitable zone of its sta...

Labels

Total Pageviews