Tag: sky

How Can A Drone Cause So Much Chaos In Airports?

In October 2017, a drone collided with a commercial aircraft in Canada, striking one of the plane’s wings. The plane sustained minor damage but was able to land safely.

Research on drone damage to aircraft is still limited but a number of institutions have tested a variety of impact scenarios and each seems to reach a different conclusion.

Other research from the Alliance for System Safety of Unmanned aircraft system through research Excellence (Assure) in conjunction with the US’s Federal Aviation Authority suggested drones could inflict more damage than a bird collision.

The lithium ion batteries that power them may not shatter upon impact, instead becoming lodged in airframes and posing a potential risk of fire.

Ravi Vaidyanathan, a robotics lecturer at Imperial College, London, told the BBC: “The threat posed to larger aircraft by drones is small but not negligible.

“The probability of a collision is small but a drone could be drawn into a turbine. A drone greater than 2kg might break the cockpit windshield as well for certain aircraft.”

Martin Lanni, chief executive of airspace security company Quantum Aviation, said: “A drone looks quite fragile but the battery is hefty and if you compare a drone to a bird, then it could be potentially more dangerous if it goes through the engine or hits the fuselage.




According to the UK Airprox Board, there were 92 instances of aircraft and drones coming close to colliding in 2017.

In the UK, legislation came into force in July, making it illegal to fly a drone within 1km (0.62 miles) of an airport. It is also illegal to fly a drone higher than 400ft (120m).

But experts have pointed out that this could be ineffective, given that a landing aircraft would fly below 400ft. And of course those with malicious intent would have little regard for legislation.

Systems have been tested in some prisons, where drones are often used to smuggle in goods, which aim to block radio signals within a certain area in order to prevent drones from landing.

For airports serious about protecting themselves from drone attacks, there is the option of a more sophisticated, if expensive, system, such as that offered by Quantum Aviation, which employs radar, radio frequency detectors and cameras to detect when drones are nearby and locate where they came from.

In an ideal world, you talk to a person but to do that you need to know where the drones are coming from,” said Mr Lanni.

“What you don’t want is to have them dropping out of the sky.”

The Quantum Aviation system can “jam” a drone – effectively stopping it working – the drone should, in theory, have a default mode that would see it either return to where it came from or land safely.

DJI, the world leader in making civilian drones, introduced geo-fencing systems in its products in 2013.

This technology can prevent drones from flying in some locations and offers warnings to drone operators flying near a restricted zone.

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Pass it on: New Scientist

Why Is The Sky Dark At Night?

That question is not as simple as it may sound. You might think that space appears dark at night because that is when our side of Earth faces away from the Sun as our planet rotates on its axis every 24 hours.

But what about all those other far away suns that appear as stars in the night sky? Our own Milky Way galaxy contains over 200 billion stars, and the entire universe probably contains over 100 billion galaxies.

You might suppose that that many stars would light up the night like daytime!

Until the 20th century, astronomers didn’t think it was even possible to count all the stars in the universe. They thought the universe went on forever. In other words, they thought the universe was infinite.

Besides being very hard to imagine, the trouble with an infinite universe is that no matter where you look in the

night sky, you should see a star.

Stars should overlap each other in the sky like tree trunks in the middle of a very thick forest.

But, if this were the case, the sky would be blazing with light. This problem greatly troubled astronomers and became known as “Olbers’ Paradox.” A paradox is a statement that seems to disagree with itself.

To try to explain the paradox, some 19th century scientists thought that dust clouds between the stars must be absorbing a lot of the starlight so it wouldn’t shine through to us.




But later scientists realized that the dust itself would absorb so much energy from the starlight that eventually it would glow as hot and bright as the stars themselves.

Astronomers now realize that the universe is not infinite. A finite universe—that is, a universe of limited size—even one with trillions and trillions of stars, just wouldn’t have enough stars to light up all of space.

Although the idea of a finite universe explains why Earth’s sky is dark at night, other causes work to make it even darker.

Not only is the universe finite in size, it is also finite in age. That is, it had a beginning, just as you and I did.

The universe was born about 15 billion years ago in a fantastic explosion called the Big Bang. It began at a single point and has been expanding ever since.

Because the universe is still expanding, the distant stars and galaxies are getting farther away all the time. Although nothing travels faster than light, it still takes time for light to cross any distance.

So, when astronomers look at a galaxy a million light years away, they are seeing the galaxy as it looked a million years ago.

The light that leaves that galaxy today will have much farther to travel to our eyes than the light that left it a million years ago or even one year ago, because the distance between that galaxy and us constantly increases.

That means the amount of light energy reaching us from distant stars dwindles all the time. And the farther away the star, the less bright it will look to us.

The universe, both finite in size and finite in age, is full of wonderful sights.

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Steve The Weird ‘Aurora’ Is Not What We Thought It Was

Well, well, well. Looks like the jig is up. The “new kind of aurora” discovered earlier this year, and subsequently named “STEVE” has been rumbled. It seems Steve isn’t an aurora after all.

But that doesn’t mean the game is over. Because Steve’s actual identity may be even more interesting. Physicists have concluded that the erstwhile aurora is in fact an entirely new celestial phenomenon.

Steve – which manifests as gorgeous glowing purple ribbons across the sky – has been around for a few decades now, known to photographers and aurora chasers, but was only brought to the attention of scientists in 2016.

It had been nicknamed Steve by the Alberta Aurora Chasers, which scientists upheld when they officially named it Strong Thermal Emission Velocity Enhancement (STEVE).

Earlier this year, researchers announced that the purple and white streamers, while very different from the shimmering green auroral curtains, were indeed a new kind of aurora.




But the light produced by Steve isn’t the same as the light produced by an aurora, so a new team of researchers worked on figuring out Steve’s mechanism by studying a Steve event from March 2008.

An aurora is generated by solar winds, which interact with charged particles in our magnetosphere, mainly protons and electrons.

These charged particles rain into the ionosphere and travel along the planet’s magnetic field lines to the poles, where they manifest as dancing lights in the sky, usually green, but sometimes red or blue, producing strong radio emissions.

This is not what is happening with Steve.

Such an event occurred on 28 March 2008, and data was obtained both by ground-based cameras that record auroras, and the NOAA’s Polar Orbiting Environmental Satellite 17, which was directly overhead at the time, and which carries an instrument that can measure charged particles raining into the ionosphere.

This instrument detected no such particles. This means the mechanism that produces Steve must be different from the mechanism that produces auroras.

For now, the researchers have named the new optical phenomenon “skyglow” (don’t worry, it’s also still Steve for now). And they have plans to learn more.

The next step in their mission to unmask the true Steve is to try and determine if streams of fast ions and hot electrons in the ionosphere are responsible for Steve, or if its source is occurring at a higher altitude.

The research has been published in the journal Geophysical Research Letters.

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How Fireworks Work? Here Is The Chemistry Behind A Firework Explosion

fireworks

It’s Independence Day, and that means it’s time for controlled explosions in the sky. No, not Texas post-rock, the great scientific display that is a fireworks show.

“Fireworks are an application of chemistry and engineering: you need good chemistry to get the effects up in the sky and good engineering to make sure they get to the right altitude and burst at the right time,” John Conkling, the former director of the American Pyrotechnics Association.

Firework shows last between 15 to 20 minutes on average, but the amount of planning and preparation that goes into producing these displays can take up to two years.




Designers need ample time to determine the right colors and shapes they want to use, and to time the explosions to the soundtrack.

There are limits on the types of chemicals you can use, however. For one, they can’t be agents that collect moisture, or else they won’t burn properly when lit.

So from its initial lighting to its final spectacular explosion, a firework’s life begins with a lit gunpowder fuse, followed by a gunpowder-boost into the sky, and finishes with an explosion of a chemical medley of fuels, oxidizers, colorants, and binders.

As you enjoy these fiery tributes this weekend, remember how much science is involved behind the rockets’ red glare.

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The 2018 Lyrid Meteor Shower Will Light Up The Sky On Earth Day.

One of the best meteor showers of the year coincides with Earth Day this year — meaning people all over the world will have the chance to see the 2018 Lyrid meteor shower light up the sky.

The Lyrids peak on April 22–23. A Half Moon may make viewing conditions difficult. Named after constellation Lyra, the Lyrids are one of the oldest known meteor showers.

What is the Lyrid meteor shower?

The Lyrid meteor shower happens annually, and according to a video from NASA’S Jet Propulsion Laboratory, it is active from April 14 until April 30 — and peaks on April 22.

It is the “first significant meteor shower in a few months,” according to AccuWeather’s astronomy blogger Dave Samuhel.




And while it is only a moderately active meteor shower, it is the oldest one on record and was first recorded by the Chinese in 687 B.C.

What stargazers see when they’re observing the Lyrid meteor shower is the Earth’s orbit coming into contact with dust left behind from a comet — in this case Comet Thatcher (C/1861 G1), which was discovered in 1861 by A.E. Thatcher.

Comet Thatcher orbits the sun roughly every 415 years, according to NASA. The debris left behind by the comet burns up in our atmosphere creating fiery streaks observed in the night sky.

A long exposure photograph shows how intense the Milky Way can be

Where is the best place to see the meteor shower?

Special equipment — telescopes, binoculars — is not necessary to view the Lyrid meteor shower, which is safe to view with the naked eye.

However, to increase your chances of seeing this annual meteor shower, it’s best to head to a dark area away from light pollution.

And while the Lyrid meteor shower should be viewable no matter your location, there are a few other variables to take into consideration: hemisphere and weather.

For those in the U.S., AccuWeather has a map showing what areas of the country will have good, fair, or poor conditions for viewing.

According to the map, those with the best optics for viewing the Lyrid meteor shower are on the East Coast from Pennsylvania to Maine as well as a swath on the West Coast that includes parts of Texas, Arizona, New Mexico, Nevada, Washington and California.

The Lyrid meteor shower “favors the Northern Hemisphere,” according to EarthSky’s McClure, because “the higher [the star] Vega climbs into your sky, the more meteors you’re likely to see.

Vega is part of the constellation Lyra — where the Lyrids get their name, because it looks like they are radiating from the constellation — and it is located in the Northern Celestial Hemisphere.

However, those in the Southern Hemisphere will have to wait until the “early hours of the morning before reasonable rates can be observed,” according to the Australian Broadcasting Corporation.

Viewers in Australia will have the best view of the meteor shower on Monday, April 23 between 2 a.m. and 4 a.m. local time.

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High-Altitude Balloon May Soon Be Giving The US Military And NASA A Low-Cost Eyes In The Sky

Arizona-based company World View successfully pulled off a five-day test flight of its specialized high-altitude balloon, which is designed to carry Earth-observing instruments to the upper edges of the atmosphere.

It’s the longest flight yet of the so-called “stratollite,” though eventually World View hopes to keep these vehicles flying for months, or even a year, at a time.

The stratollite is meant to act like a low-hanging satellite. But rather than rocket to space and then orbit the Earth, these vehicles are designed to leisurely float to more than 20 miles up in the stratosphere — and then stay there.




The stratollites “surf” the high-altitude winds in order to hover continuously over one patch of the planet.

Each stratollite balloon carries a package equipped with sensors, cameras, and other types of instruments to collect data on the Earth below.

World View envisions the technology being used for a number of applications, like weather-monitoring, communications, or disaster evacuation.

But in order to work, these vehicles have to stay put for long periods of time, and up until now, the longest stratollite flight had only lasted 27 hours.

World View also attempted a four-day mission at the end of June, sending a stratollite carrying a KFC chicken sandwich to the stratosphere. That mission ended after just 17 hours, due to a leak in the balloon.

This most recent stratollite took off on October 1st from World View’s new headquarters in Tucson — the first launch from the company’s Arizona facility.

The vehicle hovered between 55,000 and 75,000 feet, while successfully testing out equipment designed to steer the balloon and keep it relatively stable at the same spot.

On board were a 50.6-megapixel Canon EOS 5DS camera to do Earth observations, as well as communications equipment from the US military’s Southern Command.

The military is interested in using the stratollite to look for human and drug trafficking, as well as maritime piracy.

World View says it’s going to bring down the stratollite sometime today, after hitting all of its critical milestones.

This is an enormous leap in our development program and we are certain the stratollite is going to forge a new path in how we observe, react to and collect data about our planet,” Jane Poynter, CEO of World View, said in a statement.

Stratollites aren’t the only form of balloon travel that World View is focusing on. The company is also working on high-altitude balloons that can carry humans to the stratosphere, for a luxurious look at the curvature of the Earth.

This tourism venture, called the Voyager program, is already open for reservations, which run about $75,000 per ticket. However, no human flights have been scheduled yet.

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A New Study Suggests That As A Star Begins To Die And Slowly Expands Outward, It Would Temporarily Light Up As It Eats The Worlds It Hosts

600 light years away, in the constellation of Auriga, there is a star in some ways similar to our Sun. It’s a shade hotter (by about 800° C), more massive, and older.

Oddly, it appears to be laced with heavy elements: more oxygen, aluminum, and so on, than might be expected. A puzzle.

Then, last year, it was discovered that this star had a planet orbiting it. A project called WASP – Wide Area Search for Planets, a UK telescope system that searches for exoplanets — noticed that the star underwent periodic dips in its light.

This indicates that a planet circles the star, and when the planet gets between the star and us, it blocks a tiny fraction of the starlight.




The planet is a weirdo, for many reasons… but it won’t be weird for too much longer. That’s because the star is eating it.

OK, first, the planet. Called WASP 12b, it was instantly pegged as an oddball. The orbit is only 1.1 days long! Compare that to our own 365 day orbit, or even Mercury’s 88 days to circle the Sun.

This incredibly short orbital period means this planet is practically touching the surface of its star as it sweeps around at over 220 km/sec!

That also means it must be very hot; models indicate that the temperature at its cloud tops would be in excess of 2200°C.

Not only that, but other numbers were odd, too. WASP 12b was found to be a bit more massive and bigger than Jupiter; about 1.8 times its size and 1.4 times its mass.

That’s too big! Models indicate that planets this massive have a funny state of matter in them; they are so compressible that if you add mass, the planet doesn’t really get bigger, it just gets denser.

In other words, you could double Jupiter’s mass and its size wouldn’t increase appreciably, but since the mass goes up, so would its density.

But WASP 12b isn’t like that. In fact, it has a lower density than Jupiter, and is a lot bigger! Something must be going on… and when you see a lot of weird things all sitting in one place, it makes sense to assume they’re connected.

In this case it’s true: that planet is freaking hot, and that’s at the heart of this mess. Heating a planet that much would not exactly be conducive to its well-being.

When you heat a gas it expands, which would explain WASP 12b’s big size. It’s puffy! But being all bloated that close to a star turns out to be bad for your health.

Astronomers used Hubble to observe the planet in the ultraviolet and found clear signs of all sorts of heavy elements, including sodium, tin, aluminum, magnesium, and manganese, as well as, weirdly, ytterbium*.

Moreover, they could tell from the data that these elements existed in a cloud surrounding the planet, like an extended atmosphere going outward for hundreds of thousands of kilometers.

This explains the peculiar high abundance of heavy metals in the star I mentioned at the beginning of this post; they come from the planet! But not for long.

Given the mass of the planet and the density of the stream, it looks like it has roughly ten million years left. At that point, supper’s over: there won’t be anything left for the star to eat.

In reality it’s hard to say exactly what will happen; there may be a rocky/metal core to the planet that will survive. But even that is so close to the star that it will be a molten blob of goo.

The way orbits work, the way the dance of gravity plays out over time, the planet itself may actually be drawn inexorably closer to its star. Remember, too, the star is old, and will soon start to expand into a red giant.

So the planet is falling and the star is rising; eventually the two will meet and the planet will meet a fiery death.

All in all, it sucks to be WASP 12b.

But it’s cool to be an astronomer!

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Pass it on: New Scientist

Sky Watching Tips And Tricks For Cold Northern Nights

For much of the contiguous United States this winter has been marked by perpetual ice, snow as well as the now infamous polar vortex.

Such conditions might make even the most committed stargazer think twice before venturing outdoors.

Stepping outside to enjoy a view of the constellation Orion, Jupiter or even just the waxing moon these frosty nights takes only a minute or two, but if you plan to stay outside longer, remember that enjoying the starry winter sky requires protection against the cold temperatures.




The best garments are a hooded ski parka and ski pants, both of which are lightweight and provide excellent insulation. And remember your feet.

Two pairs of warm socks in loose-fitting shoes are quite adequate; for protracted observing on bitter-cold nights wear insulated boots.

Reach for the binoculars

In weather like this, one quickly will realize the advantage of using a pair of good binoculars over a telescope.

A person who attempts to set even a so-called “portable” scope up in bitter temperatures or blustery winds might give up even before he or she got started.

But binoculars can be hand-held and will produce some quickly magnified images of celestial objects before rushing back inside to escape the frigidity.

Transparency

In their handy observing guide, “The Stars” (Golden Press, N.Y.), authors Herbert Zim and Robert Baker write that “the sky is never clearer than on cold, sparkling winter nights.

“It is at these times that the fainter stars are seen in great profusion. Then the careful observer can pick out dim borderline stars and nebulae that cannot be seen when the sky is less clear.

What Zim and Baker were referring to is sky transparency, which is always at its best during the winter season. That’s because Earth’s atmosphere is not as hazy because it is less moisture laden.

Cold air has less capacity to hold moisture, therefore the air is drier and thus much clearer as opposed to the summer months when the sky appears hazier.

But this clarity can also come at a price.

Seeing through the twinkles

If you step outside on one of those “cold, sparkling nights” you might notice the stars twinkling vibrantly.

This is referred to as scintillation, and to the casual observer looking skyward, they might think of such a backdrop as the perfect night for an astronomer, but it isn’t.

This is because when looking skyward, skywatchers are trying to see the sky through various layers of a turbulent atmosphere.

Were we to train a telescope on a star, or a bright planet like Mars, what we would end up with is a distorted image that either seems to shake or quiver or simply “boils” to the extent that you really can’t see very much in terms of any detail.

Forecasting sky conditions

If you own a telescope, you don’t need to wait for balmy summer nights to get good views. Usually, a few days after a big storm or frontal passage, the center of a dome of high pressure will build in to bring clear skies and less wind.

And while the sky might not seem quite as “crisp” or “pristine” as it was a few days earlier, the calming effect of less winds will afford you a view of less turbulent and clearer images through your telescope.

More comfortable nights ahead

If you plan on heading out on a cold winter’s night — and if you’re doing it while under a dome of high pressure — the fact that there is less wind means not only potentially good seeing, but also more comfort viewing conditions.

The end of winter is in sight though. The Northern Hemisphere is officially halfway through the winter season and milder, more comfortable nights are within reach.

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SpaceX Launch Leaves Ghostly Glowing Trail In The Sky

People along the West Coast looked toward the heavens Friday to find a strange, morphing orb glowing in the night sky.

It looked like the stuff of science fiction, but it was actually the mark of a SpaceX rocket hauling a group of telecom satellites into Earth’s orbit.

The rocket took off from the Vandenberg Air Force Base in central California, and kicked up a flurry of wonder from social media users from across the state.

SpaceX CEO Elon Musk fueled the fun by teasing onlookers who were confused by the eerie contrail.

Nuclear alien UFO from North Korea,” he tweeted.




But the show was, in fact, put on by the rocket’s exhaust meeting the crisp air.

Water vapor from the aircraft engine exhaust is immediately exposed to very cold temperatures at very high altitudes.”

“The impurities in the exhausts and the very cold temperatures are the perfect recipe for a condensation trail,” writes meteorologist and Forbes contributor Marshall Shepherd.

It’s just like what airplanes leave behind when they streak across the sky.

Friday’s launch marked SpaceX’s 18th and final launch for the 2017 calendar year, making it the busiest private-sector rocket company in the world.

The mission was to deliver a group of 10 telecommunications satellites to low-Earth orbit for a company called Iridium, which is in the process of replacing its vast satellite network.

It’ll be used to deliver communications services and, among other things, track airplane traffic.

Musk took advantage of the buzz created by Friday’s spectacle to tout SpaceX’s next big feat: conducting a test launch of its massive new rocket, called Falcon Heavy.

That’s due in January.

To translate, “rocket cores” refer to the boosters at the base of the rocket.

They provide the initial thrust at lift-off. SpaceX’s defining move is to guide those boosters back to Earth for a safe landing so they can be reused in future missions.

The Falcon Heavy has three boosters, two more than SpaceX’s operational Falcon 9 rocket, and SpaceX will attempt to recover all of them.

Droneship refers to a landing pad that SpaceX sends into the ocean to capture boosters that fly out with a horizontal trajectory.

Reusing hardware is all part of SpaceX’s plan to drastically drive down the cost of spaceflight, and the company has all but mastered the move. It’s landed rockets on 20 separate occasions.

No rocket landing was attempted on Friday, however.

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Where, When, And How To Perfectly Watch This Week’s Meteor shower

One of the last meteor showers of the year is happening this Friday. So, if you haven’t caught a meteor shower yet this year, this week is your chance.

Don’t miss out on this year’s Leonid meteor shower, which is expected to have ideal conditions for many parts of the US. Following is a transcript of the video.

The Leonid meteor shower is happening this week. The most meteors will happen on the evening of Nov. 17. Expect to see between 10-20 meteors an hour. Viewing conditions will be excellent this year.




The Moon will be a paper-thin crescent. So, the night sky will be especially dark to enjoy the show.

But watch out for the weather. Cloudy skies will cover some parts of the US. Here are the best and worst places to watch on Nov. 17.

Some of the first records of the Leonids date back to the 10th century. They’re famous for some of the most spectacular meteor showers.

In the past, the Leonids have produced 50,000 meteors per hour. For the best show, find a safe, dark place away from city lights.

Many meteors will appear to come from the constellation Leo. But experts advise looking away from Leo.

That way, you’ll spot the meteors with the longest tails. Happy meteor hunting!

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