Tag: earth

Why Can’t We Feel Earth’s Spin?

Earth spins on its axis once in every 24-hour day. At Earth’s equator, the speed of Earth’s spin is about 1,000 miles per hour (1,600 kph).

The day-night has carried you around in a grand circle under the stars every day of your life, and yet you don’t feel Earth spinning.

Why not? It’s because you and everything else – including Earth’s oceans and atmosphere – are spinning along with the Earth at the same constant speed.

It’s only if Earth stopped spinning, suddenly, that we’d feel it. Then it would be a feeling similar to riding along in a fast car, and having someone slam on the brakes!




Think about riding in a car or flying in a plane. As long as the ride is going smoothly, you can almost convince yourself you’re not moving.

A jumbo jet flies at about 500 miles per hour (about 800 km per hour), or about half as fast as the Earth spins at its equator. But, while you’re riding on that jet, if you close your eyes, you don’t feel like you’re moving at all.

And when the flight attendant comes by and pours coffee into your cup, the coffee doesn’t fly to the back of the plane. That’s because the coffee, the cup and you are all moving at the same rate as the plane.

Now think about what would happen if the car or plane wasn’t moving at a constant rate, but instead speeding up and slowing down. Then, when the flight attendant poured your coffee … look out!

Earth is moving at a fixed rate, and we’re all moving along with it, and that’s why we don’t feel Earth’s spin. If Earth’s spin were suddenly to speed up or slow down, you would definitely feel it.

The constant spin of the Earth had our ancestors pretty confused about the true nature of the cosmos. They noticed that the stars, and the sun and the moon, all appeared to move above the Earth.

Because they couldn’t feel Earth move, they logically interpreted this observation to mean that Earth was stationary and “the heavens” moved above us.

With the notable exception of the early Greek scientist Aristarchus, who first proposed a heliocentric model of the universe hundreds of years B.C.E., the world’s great thinkers upheld the geocentric idea of the cosmos for many centuries.

It wasn’t until the 16th Century that the heliocentric model of Copernicus began to be discussed and understood.

While not without errors, Copernicus’ model eventually convinced the world that Earth spun on its axis beneath the stars … and also moved in orbit around the sun.

Bottom line: Why don’t we feel Earth rotating, or spinning, on its axis? It’s because Earth spins steadily – and moves at a constant rate in orbit around the sun – carrying you as a passenger right along with it.

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Pass it on: Popular Science

NASA’s Exoplanet-Hunter TESS Gets Prepped For Launch

Final preparations are underway here at Kennedy Space Center to get NASA’s next planet-hunting spacecraft, the Transiting Exoplanet Survey Satellite (TESS), ready for its planned April 16 launch.

The satellite, built by Orbital ATK, arrived here on Feb, 12 after a 17-hour drive down from Orbital’s facility in Dulles, Virginia, and was ushered inside the Payload Hazardous Servicing Facility (PHSF) to be readied for launch.

However, before it hitches a ride to space atop SpaceX’s Falcon 9 rocket, NASA invited members of the media to get a close-up look at TESS inside a specialized clean room.

The PHSF is one of the last stops a spacecraft makes before launch. Inside this unique facility, engineers conduct final tests and load hazardous fuels, such as hydrazine that will help propel the spacecraft.

Therefore, anyone who enters must follow a strict protocol, including wearing a special suit known as a bunny suit.




Before entering the clean room, a group of eager journalists were regaled with mission specifics by the TESS team, which included the mission’s principal investigator, George Ricker of MIT’s Kavli Institute for Astrophysics and Space Research.

The TESS mission, which is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and operated by the Massachusetts Institute of Technology (MIT), will spend at least two years studying more than 200,000 of the closest and brightest stars in our solar neighborhood.

TESS will scan the sky, looking for tiny dips in starlight. These dips in brightness — known as transits — could indicate that one or more planets is orbiting the star.

Ricker said that the team expects to discover several thousand planets during the spacecraft’s mission.

The Kepler Space Telescope, NASA’s planet-hunting powerhouse, has identified more than 2,000 confirmed exoplanets using the same “transit” technique as TESS.

However, TESS has a much larger field of view — nearly 20 times larger than Kepler — potentially allowing it to surpass Kepler in the number of exoplanet discoveries.

Thanks to Kepler, we now know that planets around other stars are very common. Kepler spent its primary mission staring at a narrow patch of sky to answer that very question.

Unfortunately, all of Kepler’s discoveries are too far away for follow-up study.

Scheduled to launch next year, Webb will scan the targets identified by TESS to look for water vapor, methane and other atmospheric gases. And, with a little luck, Webb might even spot signatures indicative of life beyond Earth.

TESS will launch into a high, elliptical orbit around Earth that is in a 2:1 resonance with the moon — it will orbit twice for every one time the moon goes all the way around.

This type of orbit has multiple benefits: it is very stable, meaning it won’t be affected by space debris, radiation, while allowing the spacecraft to easily communicate with the ground.

However, this type of orbit limits the number of launch opportunities, as it must be synchronized with the moon’s orbit around the Earth. After launch, it will take the spacecraft two months to reach its destination.

During our visit, engineers were prepping the spacecraft for final testing before launch. That testing included final checkouts of the solar arrays and is expected to be completed February 21.

Next, TESS will be mated to the launch vehicle.

Originally slated to launch on March 20, TESS is currently scheduled to lift off on April 16, following a one-month delay requested by the launch provider, SpaceX. However, TESS must launch by June per congressional mandate.

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Pass it on: New Scientist

Five Reasons We Know The Earth Isn’t Flat

The curvature of the Earth is visible in this 2014 photo, which ESA astronaut Samantha Cristoforetti snapped from the International Space Station.

Most of the human population is pretty sure the Earth is round.

Neil deGrasse Tyson doesn’t have to take to Twitter to confirm it, because every kind of investigation that we can do shows that the blue marble we live on is indeed marble-shaped.

Here are 5 ways we know the Earth is round, and some you can prove yourself!




1. You Don’t Weigh Less at the Horizon

While flat-earthers will contend that there is no such thing as gravity, this force unites the entire universe. It’s everything from what makes the numbers jump on a bathroom scale to the reason why planets and stars form.

It uniformly pulls everyone on the surface of Earth toward our planet’s center of mass. That’s why you’ll weigh the same in Los Angeles as you will in Jakarta.

If the Earth was flat, gravity would no longer pull everyone the same way.

If the flat Earth would be something like a disk, those at the edge of the disk would be pulled relatively sideways, while those at the center of the plate would be pulled straight down.

The difference would change your weight enough to confuse a bathroom scale. Considering that humans have been to every landmass on Earth without celebrating sudden lightness, we can rule out a flat planet.

2. You Don’t Fall Off The Planet

Where is the edge of the world according to flat-earthers? The answer changes, but it usually involves some impenetrable barrier at said edge that prevents people from going past or falling off.

Global conspiracies apparently prevent people from investigating these boundaries.

Where is the edge of the world according to flat-earthers? The answer changes, but it usually involves some impenetrable barrier at said edge that prevents people from going past or falling off.

Global conspiracies apparently prevent people from investigating these boundaries.

3. You Don’t Always See the Same Constellations

Hit up a friend in Australia and ask them what constellations they can see at night. Now tell them which ones pepper your patch of darkness.

They won’t be the same. Because the Earth is a shape other than a flat disk, when looking into the night sky the Earth itself can block your view.

If the flat Earth theory were true, everyone should be able to see the same constellations all the time, as if we all were staring up from the same section of summer grass.

4. We’ve Seen Earth From Space, From Multiple Angles

This is “Earthrise,” arguably the most famous photo ever taken. It was beamed back to us by the astronauts on the Apollo 8 mission on Christmas Eve, 1968.

It shows the Earth as a perfect (from that vantage point at least) azure orb speckled with land and clouds, and us.

It’s true that the Earth could be a disk in this photo, and the astronauts were seeing it face-on, making it appear spherical.

5. Timezones Exist

To make the seasons work with a flat Earth, advocates claim that the Sun orbits in a circle above our disk, like a tetherball on an invisible string.

But timezones exist. Try calling someone in China right now and convincing them that you are experiencing the same time of day (and then apologize).

A flat Earth can’t account for how some parts of the planet are provably in darkness while other parts are bathed in light.

the Earth is not flat. From what we know of the universe, it can’t be. A conspiracy could never be big enough to deny us our planet’s true shape.

We live on a pale blue dot, believe it or not. A dot from every angle makes a sphere, who you been listening to, this is what you should hear.

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Pass it on: Popular Science

What Would Happen If Earth Became 2 Degrees Warmer?

In 2015, the Paris Agreement declared that the world should try to keep Earth’s warming trend to well below 2°C by 2100. Here’s what would happen if temperatures did increase by 2° C.

Sea levels will likely rise by 1.6 feet. Flooding coastlines worldwide.

While the amount of fresh water may increase for high latitudes, East Africa, and parts of India and Sahel, subtropical regions may lose nearly one-third of its fresh water.

Making matters worse, heat waves could intensify. Tropical regions may experience heat waves for up to 3 months which will affect the growth of certain staple crops.




These areas will likely produce less wheat and corn but slightly more soy and rice.Which could affect overall diets worldwide.

Likewise, North Asia may see a boost in soy crops. Growing up to a quarter more soy each year.

For sea life, the situation is more dire. Warmer oceans will do irreversible damage to 99% of coral reefs. As the reefs die off, it will disrupt ecosystems for up to 9 million different species.

This scenario was forecasted by the European Geosciences Union in 2016. In 2017, another team of scientists estimated there’s a 95% chance Earth will warm more than 2 ºC by 2100.

Bleak forecasts may not be enough to stop humans from warming Earth. But at least they’re a guide on how to prepare for a frightening future.

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NASA’s New Horizons Spacecraft Snaps Image From 3.8 Billion Miles Away From Earth

At first glance it might not look like much – but, with a fuzzy purple and green photo, NASA’s New Horizons spacecraft has made history.

On December 5, New Horizons captured an image said to be the farthest from Earth ever taken, at a staggering 3.79 billion miles away.

And, just hours later, it beat its own record.

According to NASA, the remarkable false-color images sent back by New Horizons are also the closest-ever images captured of objects in the Kuiper Belt.

When New Horizon’s snapped a photo with its telescopic camera for a routine calibration frame of the Wishing Well star cluster, it was farther into space than even NASA’s Voyager 1 had been when it captured its famous ‘Pale Blue Dot’ image of Earth, the space agency says.

At the time, New Horizons was 3.79 billion miles (6.12 billion kilometers) from Earth.


Voyager, by comparison, was 3.75 billion miles (6.06 billion kilometers) from Earth when it captured its famous photo in 1990.

According to NASA, New Horizons is now the fifth spacecraft to fly beyond the outer planets of our solar system.

Hours after its first record-breaking image on Dec 5, it captured another. The latter shows a look at Kuiper Belt objects HZ84 and 2012 HE85.

The images were captured using the spacecraft’s Long Range Reconnaissance Imager (LORRI). And, NASA says they’re the closest images yet of objects in this region.

New Horizons has long been a mission of firsts – first to explore Pluto, first to explore the Kuiper Belt, fastest spacecraft ever launched,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado.

“And now, we’ve been able to make images farther from Earth than any spacecraft in history.”

New Horizons is now on its way to a KBO named 2014 MU69, with which it’s expected to make a close encounter on Jan 1, 2019.

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Pass it on: New Scientist

The Middle Booster Of SpaceX’s Falcon Heavy Rocket Failed To Land On Its Drone Ship

Though the Falcon Heavy’s outer cores successfully landed after launch this afternoon, the middle core of SpaceX’s huge rocket missed the drone ship where it was supposed to land they said.

The center core was only able to relight one of the three engines necessary to land, and so it hit the water at 300 miles per hour about 300 feet from the drone ship.

As a result, two engines on the drone ship were taken out when it crashed, SpaceX CEO Elon Musk said in a press call after the rocket launch. “[It] was enough to take out two thrusters and shower the deck with shrapnel,” he said.

It’s a small hiccup in an otherwise successful first flight. The Falcon Heavy rocket took off from NASA’s Kennedy Space Center in Cape Canaveral, Florida, at 3:45PM ET on Tuesday and made a beautiful arc to space.




About two and a half minutes after liftoff, the two outer boosters of the rocket broke away and returned to Earth.

The pair then touched down just seconds apart on SpaceX’s two ground landing pads at the Cape called Landing Zone 1 and Landing Zone 2.

At about three minutes after liftoff, the center core broke away from the upper stage — the top portion of the rocket that is carrying the Falcon Heavy’s payload, Musk’s Tesla Roadster.

It then attempted to land on SpaceX’s drone ship, but live video of the landing stalled just before the core was slated to make its touchdown. “We lost the center core,” someone said on a separate, unlisted live stream of the launch.

Meanwhile, the upper stage seems to be doing just fine. After launch, Musk tweeted that it had successfully ignited its engine and raised its orbit as intended.

Now, the upper stage will spend about six hours coasting through space — a move by SpaceX to demonstrate a tricky orbital maneuver for the US Air Force.

That coast will take the rocket through regions of intense radiation that surround Earth called the Van Allen belts, where it will be pelted by high-energy particles.

If the vehicle is still operating as it should by then, the upper stage will do another engine burn, putting the car on its deep space path to Mars’ orbit.

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Pass it on: New Scientist

A Powerful Earthquake In Alaska Didn’t Trigger A Big Tsunami

Last Tuesday night, a magnitude 7.9 earthquake struck southeast of Kodiak Island in the Gulf of Alaska, prompting a tsunami warning that forced people to flee to higher grounds in the middle of the night.

Fortunately, the tsunami waves were less than a foot high, and the advisories were canceled a little after 4AM local time. So why was Alaska so lucky?

Powerful quakes that happen out at sea are known to cause destructive tsunamis. In 2011, a magnitude 9 earthquake in northeastern Japan triggered waves as high as 126 feet, killing nearly 20,000 people.




In 2004, a similarly strong quake off the coast of Indonesia caused a tsunami that killed more than 200,000 people.

Alaska also has a history of strong earthquakes: in 1964, the state experienced the most powerful quake ever recorded in the US, a 9.2 magnitude tremor followed by a tsunami that killed over 100 people.

Earthquakes occur because the Earth’s crust is divided into plates. These plates can move smoothly against each other or become stuck.

When they become stuck, they build up strain over time, until one day, the plates unstick, releasing energy that causes an earthquake.

Just south of Alaska, the Pacific plate is sliding underneath the North American plate, an area called the subduction zone. That’s why the state is highly seismic, Blakeman tells said.

Last Tuesday night’s earthquake generated because of all the strain building up on the subduction zone, but it did not occur exactly on a fault where the Pacific Ocean seafloor is sliding under the North American plate, Blakeman says.

Instead, the quake occurred a little farther out, in a place where the fault is moving horizontally.

This type of quake, called a strike-slip earthquake, is less likely to trigger large tsunamis, and this is probably why Alaska only saw waves of less than a foot, according to Blakeman.

When earthquakes happen on the subduction zone itself, where one plate is pushing down while the other is going up, then high waves form.

To get a tsunami, you have to have substantial vertical movement on the seabed,” Blakeman says. Those types of earthquakes were responsible for the massive tsunamis in Japan and Indonesia.

Aftershocks in Alaska could continue for weeks or months, Blakeman says. If the quakes generate from the same zone as last night, then large tsunamis should not be expected.

But because the state sits by the Pacific-North America plate boundary, it’s normal that new earthquakes will happen in the future. When and where, exactly?

That’s impossible to say. Earthquakes are so complicated that scientists aren’t able to predict them — at least not yet. “Since we can’t predict them, all we can do is be prepared,” Blakeman says.

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Pass it on: Popular Science

Incredible Dashcam Footage Shows Giant Fireball Hurtling Towards Ground In Michigan Before Sparking 2.0 Magnitude Earthquake

The impressive dash-cam footage, recorded from a vehicle traveling on a motorway near the US city Detroit, shows a dazzlingly bright object hurtling towards the ground.

Other clips posted on social media also show the meteorite lighting up the night sky. Terrified onlookers posted dramatic footage and images of the cosmic event online.

It sparked a 2.0 magnitude earthquake near Detroit eastern Michigan, and a powerful explosion that shook homes.




The National Weather Service said: “After reviewing several observational data sets, we can confirm the flash and boom was NOT thunder or lightning, but instead a likely meteor.

The United States Geological Survey late confirmed a meteorite had been seen and heard in the area.

Meteors, also known as shooting stars, are created when little chunks of rock and debris in space fall through a planet’s atmosphere.

They leave a bright trail as they are heated by the friction of the atmosphere. If they hit the ground, they become a meteorite.

On Twitter, people reacted with shock at the phenomenon. “Did Michigan just get hit with a meteor? A bomb? A UFO?” one person said.

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What Would Life Be Like On The TRAPPIST-1 Planets?

The TRAPPIST-1 system is home to seven planets that are about the size of Earth and potentially just the right temperature to support life.

So how would life on these alien worlds be different than life on Earth? Here are some of the major differences.

Amazing night-sky views

Perhaps one of the most dramatic things that visitors to the TRAPPIST-1 system would notice is the view of the other six planets in the sky.

In some cases, a neighboring planet might appear twice as large as the full moon seen from Earth.

All seven of the known planets in the TRAPPIST-1 system orbit closer to their star than Mercury orbits the sun.




The innermost planet and the outermost planet are almost 30 times closer together than Earth and Venus at their largest separation.

The reason these seven planetary siblings can fit into such tight orbits is because their parent star is an ultracool dwarf star. It’s about 2,000 times dimmer than the sun, and only slightly larger than the planet Jupiter.

Three of the known planets orbit the star in what’s known as the “habitable zone,” or the region around a star where the planet could have a surface temperature right for liquid water.

The position of the habitable zone is different around each star — on a very dim star like TRAPPIST-1, which radiates significantly less heat than the sun, the habitable zone lies much closer to the star.

But there’s no guarantee that a planet in the habitable zone of TRAPPIST-1 can host liquid water on its surface.

Without an atmosphere, water won’t remain a liquid in space. For example, on comets, water ice sublimates directly into a vapor when it is heated by the sun.

Perpetual twilight

Even though the seven known planets in the TRAPPIST-1 system orbit extremely close to their parent star, the natural lighting on these planets would seem very dim to a human visitor.

Ultracool dwarf stars produce significantly less radiation than sun-like stars, and most of TRAPPIST-1’s light is radiated in the infrared wavelengths rather than visible wavelengths, according to Amaury Triaud of the Institute of Astronomy at the University of Cambridge in England, a co-author on the paper describing the discovery.

Short years, eternal days (and nights)

The TRAPPIST-1 planets take almost no time at all to make one complete orbit around their parent star. Six of the planets make a complete an orbit in anywhere from 1.5 to 12.4 days.

That means one “year” (or what scientists call the orbital period) on most of these planets is less than two weeks on Earth. But the orbital period of these planets is slightly upset by their neighbors.

Even though the years are short in the TRAPPIST-1 system, the days would be very long — almost eternal, because the according to the scientists behind the discovery, it’s very likely the seven planets are tidally locked, meaning that one side of each planet is always facing the star.

The moon is tidally locked to Earth, which is we see only one side of our lunar companion (at least from the ground).

There’s some debate about whether or not a tidally locked planet could host life.

Some tidally locked planets might be uninhabitable because the side facing the star would become extremely hot, while the other side would grow extremely cold.

But some models show that if the planet’s atmosphere can dissipate heat across the planet’s surface, then life could still find a welcoming home there.

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Pass it on: New Scientist

‘Megastorms’ That Throw Thousand-Tonne Boulders Over Clifftops May Be On Their Way Back Thanks To Global Warming

Standing atop a 60-foot cliff overlooking the Atlantic, James Hansen — the retired NASA scientist sometimes dubbed the “father of global warming” — examines two small rocks through a magnifying glass.

Towering above him is the source of one of the shards: a huge boulder from a pair locals call “the Cow and the Bull,” the largest of which is estimated to weigh more than 1,000 tons.

The two giants have long been tourist attractions along this rocky coast. Perched not far from the edge of a steep cliff that plunges down into blue water, they raise an obvious question: How did they get up here?




Compounding the mystery, these two are among a series of giant boulders arranged in an almost perfect line across a narrow part of this 110-mile-long, wishbone-shaped island.

Hansen and Paul Hearty — a wiry, hammer-slinging geologist from the University of North Carolina at Wilmington who has joined him here as a guide — have a theory about these rocks.

It’s so provocative — and, frankly, terrifying — that some critics wonder whether the man who helped spawn the whole debate about the dangers of climate change has finally gone too far.

The idea is that Earth’s climate went through a warming period just over 100,000 years ago that was similar in many ways to the warming now attributed to the actions of man.

And the changes during that period were so catastrophic, they spawned massively powerful superstorms, causing violent ocean waves that simply lifted the boulders from below and deposited them atop this cliff.

If this is true, the effort kicking off in Paris this week to hold the world’s nations to strict climate targets may be even more urgent than most people realize.

Hearty, an expert on Bahamas geology, first published in 1997 the idea that Cow and Bull were hurled to their perch by the sea.

Since then, Hansen has given the work much added attention by framing the boulders as Exhibit A for his dire view of climate change — which has drawn doubters in the scientific community.

But as Hansen examines the rocks on a recent morning, Hearty explains some of the evidence.

In particular, Hearty points out that the tiny grains that constitute the boulder rocks are more strongly cemented together and less likely to crumble than other rocks nearby, a sign that the boulders are older than what’s beneath them.

While there is a suggestion in the scientific literature that the boulders were simply left behind after surrounding rocks eroded away, Hearty and another leading Bahamas geology expert, Pascal Kindler of the University of Geneva in Switzerland, agree that the boulders are older than the surface upon which they rest and, thus, probably were moved by the sea.

Even the tourist placard near here takes their side, saying the ocean “lifted them atop the ridge.” But exactly how it could have done that is another matter.

Scientists have tended to attribute odd boulders such as these to tsunamis — there’s little doubt they have the power to move large rocks.

One recent study found that in the Cape Verde islands, 73,000 years ago, a 300-foot-high mega-tsunami carried boulders as large as 700 tons atop a cliff almost as high as the Eiffel Tower.

But more recent studies have also attributed large boulder movements to storms. And now into the fray has stepped Hansen, who, in 1988 testimony before Congress, put the climate issue on the map by contending — correctly, as it turned out — that global warming had already begun.

If he is also right about the boulders, Earth could be in for a rough ride.

And even if not, one thing is clear: Cow and Bull present a scientific mystery whose solution may serve as a reminder of just how violent and dynamic a planet we live on.

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Pass it on: New Scientist