Tag: NASA

Will an asteroid hit Earth? Frequent Asteroid Questions (FAQ)

Should I be worried about asteroids hitting Earth?

No, and yes. You shouldn’t lose sleep over it because damaging asteroids do not hit very often.

But you should care about it: they have hit and dangerous asteroids will hit again, unless we prevent that from happening—which we can if we put in the work to find, track, characterize asteroids, develop methods to deflect dangerous asteroids, and internationally coordinate and educate.

What is an asteroid, exactly?

An asteroid is a small, rocky or metallic object orbiting the Sun. They are now usually defined as being larger than 1 meter in diameter with objects smaller than that being called meteoroids.

The largest asteroid is Ceres at 965 km (600 mi) diameter. Most asteroids, including Ceres, are located in the asteroid belt between Mars and Jupiter, but some asteroids come near to or cross Earth’s orbit.

How do asteroids form? Where do asteroids come from?

Asteroids are typically material left over from the period of planetary formation 4.5 billion years ago, the stuff left over that didn’t form into planets in the inner solar system.  Often they are fragments of collisions between asteroids in the past.




How many near-Earth asteroids are there?

Using the cut-off for asteroid diameter of 1 meter, there are estimated to be more than half a billion near-Earth asteroids.

For objects that cause major damage if they hit Earth (larger than about 30 meters), there are about a million. So far, we are approaching 20,000 found.

It is easier to find larger objects, so we think we have found more than 90% of the asteroids 1 km and above, but for smaller asteroids still capable of causing major regional damage, we have only found a small percentage.

Are there any asteroids heading for Earth?

There are a few asteroids that currently are known to have a low probability of hitting Earth in tens to hundreds of years.

What are near-Earth objects and how could they affect us?

For example, one of the highest probabilities currently is an approximately 37 meter diameter asteroid called 2000 SG344 that has a 1 in 1100 chance of impact in 2071.

But these always are based on asteroid observations that have uncertainties in them. Usually, as more observations are obtained, the impact probability will drop to 0; in other words we know it won’t hit.

JPL keeps an online list of all asteroids with any probability of hitting Earth.

The big uncertainty is that we haven’t discovered most of near Earth asteroids yet, so we don’t know if they are on a collision course with Earth, which is why finding and tracking them is crucial.

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Moon Dust Is Super Toxic to Human Cells

In space, they say, no one can hear you sneeze. But Apollo 17 astronaut Harrison Schmitt was doing a lot of that inside the Challenger command module when he visited the moon in 1972.

One day, after a lunar walk, Schmitt accidentally breathed in some of the abundant moon dust that he and his commander had tracked back in to the Challenger living quarters.

For a full day, Schmitt suffered from what he described as “lunar hay fever.” His eyes watered, his throat throbbed, and he broke into a sneezing fit.

No, Schmitt wasn’t allergic to the moon. NASA scientists now understand that pieces of moon dust — especially the smallest, sharpest particles — pose clear health risks to astronauts.

A recent study published in the April issue of the journal GeoHealth examined exactly how dangerous that dust can be on a cellular level — and the results are as ominous as the dark side of the moon.

In several lab tests, a single scoop of replica moon dust proved toxic enough to kill up to 90 percent of the lung and brain cells exposed to it.




A dusty dilemma

Dust on the moon behaves a little differently than dust on Earth. For starters, it’s sharp. Because there’s no wind on the moon, the dust never erodes.

Instead, grains of moon dust — which are largely the products of micrometeorite impacts — remain sharp and abrasive and can easily slice into an astronaut’s lung cells if breathed in too deeply.

On top of this, moon dust can float. With no atmosphere to protect the moon from constant bombardment by solar winds and the charged particles they carry, lunar soil can become electrostatically charged like clothing with static cling.

This charge can be so strong that the soil particles actually levitate above the lunar surface,” the authors wrote in the new study.

From there, it’s easy enough for dust to cling in the nooks and crannies of an astronaut’s spacesuit and follow him or her back inside living quarters.

These loose particles can clog sensitive equipment, jam zippers, ruin clothing and — as Schmitt discovered — wreak havoc on the human body if accidentally ingested by astronauts.

But as humans explore the moon in future decades, chance exposures are likely, the researchers wrote.

Fortunately, NASA has taken this problem seriously for a long time and is developing several dust-mitigation methods.

One promising strategy: Cover sensitive surfaces with an Electrodynamic Dust Shield — essentially, electrically charged panels that shoot currents through thin wires to zap dust away.

Early lab tests have shown that the shields work well, and some sample panels are currently being tested on the International Space Station. Whether the panels could be incorporated into astronauts’ spacesuits remain to be seen.

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Why Do People Believe The Moon Landing Is A Hoax

From Apollo 15.

Forty-nine years ago Friday, the Apollo 11 spacecraft delivered the first astronauts to the surface of the moon.

The footprints Buzz Aldrin left in lunar soil are still around — and so are the throngs of conspiracy theorists who claim the entire landing was faked.

For one thing, they argue, the flag the crew planted seemed to flutter in videos, which shouldn’t happen since there’s no wind on the moon. Besides, wouldn’t mini-meteors have killed the astronauts the moment they ventured outside?

The “moon landing hoax” was among the first conspiracy theories to gain traction with the American public. In the years since, the theories have multiplied like jack rabbits, swarming all corners of the cultural landscape.

After the terrorist attacks of Sept. 11, 2001, some fringe activists insisted the U.S. government, rather than al-Qaeda, had planned the attacks.

Conspiracies about President Trump’s ties to Russia compete with all the real news on the topic.

Pizzagate” conspiracists claimed Hillary Clinton was operating a pedophile ring in a D.C. pizza parlor, leading one true believer to fire a gun in the restaurant.

It’s tempting to dismiss conspiracy theorists as wearers of tinfoil hats. But the theories should be taken seriously for their effects on political and social discourse — and research suggests that, under the right circumstances, many people are susceptible to their allure.




While people’s attraction to conspiracy theories might seem illogical, it stems from a very logical desire to make sense of the world.

Assigning meaning to what happens has helped humans to thrive as a species, and conspiracy theories are internally cohesive stories that “help us to understand the unknown whenever things happen that are fearful or unexpected,” said Jan-Willem van Prooijen, a social psychologist at Vrije University in Amsterdam.

For some believers, the sense of comfort and clarity such stories bring can override the question of their truth value.

Conspiracy theorists often have a high degree of tolerance for contradiction that allows them to ignore evidence against their theories.

Conspiracy theories also supply a seductive ego boost. Believers often consider themselves part of a select in-group that — unlike the deluded masses — has figured out what’s really going on.

Rejection and hardship can intensify people’s need to believe a story that empowers them or justifies their situation, whether the story is true.

People who are dissatisfied with the state of the world — such as the unemployed or those who support extreme ideologies — are highly vulnerable to conspiracy theories, van Prooijen said: “If people are satisfied, they are less likely to pursue this sort of theory.

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NASA Craft Shows Tiny Asteroid Studded With Boulders

NASA’s first look at a tiny asteroid shows the space rock is more moist and studded with boulders than originally thought.

Scientists released the first morsels of data collected since their spacecraft Osiris-Rex hooked up last week with the asteroid Bennu, which is only about three blocks wide and weighs about 80 million tons.

Bennu regularly crosses Earth’s orbit and will come perilously close in about 150 years. There is no liquid water on the asteroid, but there is plenty of it in the form of wet clay.

Project scientist Dante Lauretta of the University of Arizona said the blueish space rock is “a little more rugged of an environment than we expected” with hundreds of 10-metre boulders, instead of just one or two.

There’s also a bigger 50-metre boulder which looks like two cones put together with a bulge on its waistline.

Scientists think Bennu is a leftover from the beginning of the solar system 4.5 billion years ago when planets tried to form and some failed.

Mr Lauretta said it looks like Bennu was once a chunk of a bigger asteroid that probably had water in it.




When Osiris-Rex starts orbiting Bennu in January — no easy feat since its gravity is 100,000 times less than Earth’s — it will be the smallest object that a human-made spacecraft has circled.

Scientists will spend a year scouting the space rock for a good location and then in 2020 it will dive close to the surface and a robotic arm will shoot nitrogen puffs into the soil and collect grains of dirt.

Those asteroid bits will be returned to Earth in 2023.

The 800 million dollar (£636 million) Osiris-Rex mission began with a 2016 launch from Cape Canaveral, Florida. Its odometer read 1.2 billion miles last week.

The spacecraft and asteroid names come from Egyptian mythology. Osiris is the god of the afterlife, while Bennu represents the heron and creation.

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NASA’s InSight Snaps Some Selfies And Prepares To Get To Work

If you visit Mars and don’t take a selfie, did the interplanetary trip even count?

NASA’s InSight lander just flexed its 6 foot (2 meter) telescopic arm, and used it to take some more pictures of its dusty Martian surroundings.

The plan is to use the arm to very gently pick up scientific instruments from the lander’s deck and place them next to it on the Martian soil.

A special camera attached to InSight’s elbow is looking for a suitable spot for each of its scientific instruments.

If it succeeds, it’ll be the first time any rover has placed an object on the surface of another planet using a robotic arm, NASA pointed out in an update.




But that process is going to take a while: the team at the Jet Propulsion Lab will deploy InSight’s instruments over a period of two to three months.

So far, the engineers have just been running the instruments through tests to find out if they’re working properly.

“We did extensive testing on Earth. But we know that everything is a little different for the lander on Mars, so faults are not unusual,” says project lead Tom Hoffman of JPL, as quoted in NASA’s update.

They can delay operations, but we’re not in a rush. We want to be sure that each operation that we perform on Mars is safe, so we set our safety monitors to be fairly sensitive initially.”

Seeing pictures taken on the Martian surface will never get old. By next week, we’ll get an even more detailed view, so stay tuned.

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Listen To The Sounds Of Wind On Mars, Recorded by NASA’s InSight Lander

Before you listen, hook up a subwoofer or put on a pair of bass-heavy headphones. Otherwise, you might not hear anything.

Then listen.

That’s the sound of winds blowing across NASA’s InSight lander on Mars, the first sounds recorded from the red planet. It’s all the more remarkable because InSight — which landed last week — does not have a microphone.

Rather, an instrument designed for measuring the shaking of marsquakes picked up vibrations in the air — sound waves, in other words.

Winds blowing between 10 and 15 miles per hour over InSight’s solar panels caused the spacecraft to vibrate, and short-period seismometers recorded the vibrations.

The seismometers act as the cochlea, the parts of your ears that convert the vibrations into nerve signals. They are able to record vibrations up to a frequency of 50 Hertz — audible to human ears as a low rumble.

NASA also produced a version of the recording that lifted the sounds by two octaves.




A second instrument, an air pressure sensor that is part of InSight’s weather station, also picked up sound vibrations, although at a much lower frequency that can be heard perhaps by elephants and whales, but not people.

Here is a sound recording of those pressure readings, sped up by a factor of 100, which raises the pitch by about six octaves.

The sounds are so low in part because the instruments are not sensitive to higher frequencies. But the air on Mars is also extremely thin — about 1 percent of the density of Earth’s — and that favors low-frequency sounds.

The two Viking landers that NASA sent to Mars in 1976 also carried seismometers that captured some wind noise. But Dr. Banerdt said those recordings were at much lower sampling rates and did not pick up anything at audible frequencies.

NASA’s next rover, to launch in 2020, will also carry a microphone.

This is not the first time sound has been recorded on another planet. Back in the 1980s, two Soviet spacecraft, Venera 13 and Venera 14, recorded sounds from the surface of Venus.

And Europe’s Huygens lander, which was carried to Saturn’s biggest moon, Titan, by the Cassini spacecraft, also sent back sounds picked up by a microphone.

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How the Mars Moon Phobos Got Its Grooves?

The weird linear grooves scoring the surface of the Mars moon Phobos were likely carved by boulders knocked loose by a giant impact, a new study suggests.

That impact created Phobos’ most notable feature — the 5.6-mile-wide (9 kilometers) Stickney Crater, which is about one-third as wide as the moon itself.

These grooves are a distinctive feature of Phobos, and how they formed has been debated by planetary scientists for 40 years,” study lead author Ken Ramsley, a planetary scientist at Brown University in Providence, Rhode Island, said in a statement.

We think this study is another step toward zeroing in on an explanation.

Mars has two tiny moons — Phobos and Deimos, both of which the Red Planet may have nabbed from the nearby asteroid belt long ago.




Phobos’ parallel grooves were first spotted in the 1970s by NASA’s Mariner and Viking missions. In the decades since, researchers have advanced many hypotheses to explain their origin.

For example, they may have been carved by material blasted off Mars by powerful impacts. Or they could be strain marks showing that Mars’ gravity is tearing Phobos apart.

Or bouncing, rolling boulders freed by the Stickney-causing impact could have created the grooves. This idea was first advanced in the late 1970s by researchers Lionel Wilson and Jim Head, the latter of whom is a co-author on the new study.

In the new work, the researchers used computer models to simulate how debris set in motion by the Stickney smashup may have traveled across Phobos’ surface.

The model is really just an experiment we run on a laptop,” Ramsley said in the same statement. “We put all the basic ingredients in, then we press the button and we see what happens.

What happened supports the rolling-boulder idea, study team members said. In the simulations, for example, rocks set in motion by the Stickney impact tended to travel on parallel paths, matching the observed groove patterns.

In addition, some of the simulated boulders traveled all the way around Phobos, rolling over the tracks of their fellow bounders. This could explain an oddity of the actual grooves — that some of them overlay one another.

There’s another puzzling aspect of the Phobos features — a weird “dead spot” free of grooves. But the new modeling work has an answer for that, too: The dead spot is a low-elevation area just beyond a slight “lip” of rock.

It’s like a ski jump,” Ramsley said. “The boulders keep going, but suddenly there’s no ground under them. They end up doing this suborbital flight over this zone.”

All in all, the work “makes a pretty strong case” that the “rolling-boulder model accounts for most if not all the grooves on Phobos,” Ramsley said.

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NASA Probe Arrives at Asteroid Bennu on Monday

I hope you’re not all partied out after the InSight lander’s successful touchdown on Mars this week, because there’s another big spaceflight event just around the corner.

NASA’s OSIRIS-REx probe will officially arrive at the near-Earth asteroid Bennu at about 12 p.m. EST (1700 GMT) today, Monday (Dec. 3), ending a 27-month deep-space chase.

NASA will mark the occasion with a special webcast event from 11:45 a.m. to 12:15 p.m. EST (1645 to 1715 GMT), which you can watch live here at Space.com, courtesy of NASA TV.

The space agency will also air an “arrival preview program” at 11:15 a.m. EST (1615 GMT). You can catch that here at Space.com as well.

The $800 million OSIRIS-REx mission launched on Sept. 8, 2016, embarking on a looping trek toward the 1,640-foot-wide (500 meters) Bennu.

Upon arrival, the probe will take up a position about 12 miles (20 kilometers) from the space rock, NASA officials said.

OSIRIS-REx will then fly by Bennu repeatedly over the next four weeks, gathering data that will help mission team members establish the asteroid’s mass.

With this information in hand, OSIRIS-REx will slide into orbit around the space rock on Dec. 31 — just hours before NASA’s New Horizons probe cruises past the distant object Ultima Thule, billions of miles from Earth.




The diamond-shaped Bennu will then become the smallest object ever to be orbited by a spacecraft.

OSIRIS-REx will study the rock from orbit for the next 18 months or so and then make its way down to Bennu’s surface to grab a sizeable sample of material in mid-2020.

The spacecraft will depart the asteroid in March 2021, and the sample will come down to Earth in a special return capsule in September 2023.

Scientists around the world will study this material, looking for clues about the role that carbon-rich asteroids such as Bennu may have played in bringing the building blocks of life to Earth.

OSIRIS-REx — which is short for “Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer” — will also make significant contributions in other ways, mission team members have said.

For example, the probe’s measurements should help researchers better understand the resource potential of Bennu-like space rocks.

And other data will increase knowledge of how asteroids move through space, which in turn should improve predictions of where hazardous rocks are headed.

Bennu is itself a potentially dangerous asteroid; there’s a very small probability that it could hit Earth in the late 22nd century.

OSIRIS-REx isn’t the only active asteroid-sampling mission. Japan’s Hayabusa2 spacecraft is currently orbiting the 3,000-foot-wide (900 m) Ryugu, which shares Bennu’s diamond shape.

Hayabusa2 will grab a Ryugu sample next year and return it to Earth in late 2020, if all goes according to plan.

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Mars 2020 Rover Will Land at Ancient Lakebed to Search for Signs of Life

Scientists have identified 24 ancient lakes on Mars that once overflowed and burst through their walls, forming steep-sided canyons — and NASA’s Mars 2020 rover will explore the neighborhood of one of these paleolakes, looking for traces of ancient life.

Jezero Crater is one of two dozen sites that a team of geologists examined for signs of how canyons formed: by massive individual flooding events or by slower flows over longer periods of time.

Their findings suggest that for the chosen canyons, the former occurred, with a sudden flood rapidly carving canyons across the Martian surface.

These breached lakes are fairly common and some of them are quite large, some as large as the Caspian Sea,” lead author Tim Goudge, a geoscientist at the University of Texas at Austin, said in a statement.

So we think this style of catastrophic overflow flooding and rapid incision of outlet canyons was probably quite important on early Mars’ surface.”




The team came to that conclusion by looking at the relationship between the canyon measurements and the crater rims that once enclosed all that water.

Because the canyon size increased in proportion to the size of the nearby lake, the team believes that all 24 lakes violently burst through their walls, carving the canyons in perhaps just a few weeks.

If they hadn’t seen such a correlation, they would have instead suspected that the canyons formed gradually from more gentle water flow.

And unlike geologic features here on Earth, lake beds and canyons remain etched on the surface of Mars, since there are no modern plate tectonics to shuffle crust around and destroy them.

That long-lived Martian surface offers scientists hope that they might be able to access ancient sediments that may hold the remains of any life that once existed on Mars.

That’s part of why NASA chose to send its Mars 2020 rover, due to touch down on the Red Planet in 2021, to Jezero Crater, where it can study five different types of rock and hunt for any remains of ancient life that could be hiding in such a formerly wet environment.

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Days Away From Mars, NASA Awaits ‘The Seven Minutes Of Terror’

Flying the freeway to Mars, the robotic probe InSight nears the end of its 301-million-mile cruise with nary a hitch and hardly a hiccup.

But looming just ahead is the exit ramp—the Martian atmosphere.

There’s a classic term for it,” says Rob Grover of the Jet Propulsion Laboratory in Pasadena, California. “The seven minutes of terror.”

That’s approximately the time InSight takes to land, a spooky 70-mile descent from the top of the atmosphere down to the ground. “There is very little room for things to go wrong,” says Grover.

Yet hundreds of things must go right, all without NASA’s backseat driving; during landing, there’s no joysticking.

We can’t fly the vehicle in ourselves. The flight computer on board has to do it on its own. Everything has to work perfectly by itself.” And for those seven minutes, “our hearts will be pounding.

InSight lands November 26, the Monday after Thanksgiving, at 11:47 AM Pacific Time (2:47 PM Eastern).




Before the clock starts, the cruise stage—its delivery done—detaches from the capsule containing the lander. Then the capsule—just before reaching the atmosphere—points itself, “tilting down 12 degrees,” says Grover.

NASA’s leeway is minuscule, only “plus or minus a quarter of a degree.” Too shallow an angle, and the spacecraft skips off the atmosphere. Too steep, and it burns up.

And now the terrifying part. InSight thunders in at 12,300 miles per hour—almost three-and-a-half miles per second. Friction roasts it. The temperature on the heat shield hits 2,700 degrees Fahrenheit.

Friction also brakes it; within two minutes, the speed of the spacecraft slows by more than 90 percent. Yet it’s still going 1,000 miles per hour.

At seven miles up—commercial airliners fly about that high—the parachute opens. Within 15 seconds, the heat shield jettisons. For the first time, the lander is exposed to Martian air.

Another 10 seconds, and the three legs deploy. One mile above the ground, the lander falls from the backshell. Descent engines turn on. Touchdown velocity is 5 miles per hour.

Much could happen. The parachute might not open properly. The falling heat shield could graze the lander. Descent engines may not shut off. A large surface rock could sit in the way. One of the legs might not release and lock.

Those scenarios, though unlikely, are not implausible. Any of them could cause an erratic landing. Right now, atmospheric dust is minimal; weather at the landing site appears normal.

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