Tag: science

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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Pass it on: Popular Science

Fossil Fuel Emissions Have Climbed For A Second Straight Year

In the United States, emissions of carbon dioxide are projected to increase 2.5 percent in 2018 after a decade of declines.

We thought, perhaps hoped, emissions had peaked a few years ago,” said Jackson, a professor of Earth system science in Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).

After two years of renewed growth, that was wishful thinking.

Culprits for the increase include unusual weather — a cold winter in Eastern states and a warm summer across much of the nation ramped up energy needs for seasonal heating and cooling — as well as a growing appetite for oil in the face of low gas prices.

Consumption of one fossil fuel, however, is no longer on the rise: coal. The study shows coal consumption in Canada and the United States has dropped by 40 percent since 2005, and in 2018 alone the U.S. is expected to take a record-setting 15 gigawatts of coal-fired capacity offline.




Market forces and the drive for cleaner air are pushing countries toward natural gas, wind and solar power,” Jackson said. “This change will not only reduce CO2 emissions but will also save lives lost to air pollution.”

Yet the study shows renewables around the world are largely coming online as add-ons to fossil fuel energy sources — particularly natural gas — rather than replacements. “It isn’t enough for renewables to grow,” Jackson said.

They need to displace fossil fuels. So far, that’s happening for coal but not for oil or natural gas.”

Over time, the researchers warn increased coal use in regions where large swaths of the population lack access to reliable electricity could eventually exceed the steep cuts to coal use elsewhere.

India’s emissions, for example, are projected to grow by 6 percent this year as the country races to build new power plants for both industrial and consumer needs.

They’re building everything — wind, solar, nuclear and coal — very quickly,” Jackson said.

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Pass it on: New Scientists

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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Pass it on: New Scientist

Do You Have Neanderthal DNA? The Shape of Your Skull May Tell.

A Neanderthal skull (left) has a different shape from a human skull (right)

The shape of your brain may say a lot about the Neanderthal in you.

New research has found that modern humans carrying certain genetic fragments from our closest extinct relatives may have more oblong brains and skulls than other people.

Modern humans possess unique, relatively globular skulls and brains. In contrast, the closest extinct relatives of modern humans, Neanderthals, have the elongated skulls and brains that are typical of most primates.

Previous research had suggested these contrasting skull shapes might reflect differences in the size of various brain regions in modern humans and Neanderthals, and how these brain areas were wired together.

However, brain tissue doesn’t fossilize, so the underlying biology has remained elusive,” co-lead study author Philipp Gunz, a paleoanthropologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany said.

To help solve this mystery, scientists first took CT scans of seven fossil Neanderthal skulls and 19 modern human skulls. They developed imprints of the interiors of the skulls’ braincases and measured their roundness.

Next, the researchers analyzed nearly 4,500 modern humans for whom they had both genetic data and magnetic resonance imaging (MRI) scans of their brains.




We reasoned that if we could identify specific Neanderthal DNA fragments in a large enough sample of living humans, we would be able to test whether any of these fragments push towards a less globular brain shape, allowing us to zoom in on genes that might be important for this trait,” senior study author Simon Fisher, a neurogeneticist at the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands said.

The Neanderthal DNA fragments contained two genes previous research linked to brain development.

One, UBR4, is linked with the generation of neurons, and the other, PHLPP1, is associated with the development of fatty insulation around nerve cells.

The scientists noted that if a person has more Neanderthal DNA than average, that does not necessarily mean their brain is more oblong.

The Neanderthal brain had a different shape from our brains

Two people who have very similar total amounts of Neanderthal DNA — for example, 1 percent of their genomes — may well carry completely different fragments,” Fisher said.

The researchers also noted these skull differences likely did not reflect any differences at the time of an infant’s birth: Modern humans and Neanderthals have similar braincase and skull shapes at that time, Gunz said.

After birth, differences in brain development likely resulted in the pronounced differences that are found in skull shape between adults of the two lineages, he added.

Future research can look for more Neanderthal DNA linked with modern human brains and determine what specific effects these ancient genetic variants might have by growing brain tissue with Neanderthal DNA in the lab, Fisher said.

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Pass it on: New Scientist

How Atomic Bombs Help Catch Art Forgeries

Art forgery is a multi-million dollar business, one that museums and appraisers are constantly battling. But there is one technique they’ve found to foil forgers that’s near foolproof – and it involves atomic bombs.

Wolfgang Beltracchi is an artist who got his start as a forger of classic masters like Picasso, Van Gogh, and others. But he and those in his business found a foil in Peggy Guggenheim, Dr. Elena Basner, and a cadre of scientists that found a technique that searches for traces of the isotopes cesium-137 and strontium-90.

The reason is that these isotopes are only created by fission of Uranium 235, and between 1945 and 1963, 522 open-air atomic bomb blasts scattered these isotopes into the atmosphere, which then got into the soil, made its way into flax plants, which were used to create linseed oil, which was used as a binding agent in paint.

So if a painting shows traces of these isotopes in the paint, there is no way that it was created before 1945.

This technique has foiled hundreds of art forgers in the years since and has proven to be one of the most difficult challenges for future Wolfgang Baltracchis.

China Launches Lunar Rover To Far Side Of The Moon

China is poised to become the first country to explore the far side of the moon with the launch of a lunar rover Saturday, another step to its goal of becoming a space superpower.

The Chang’e 4 lunar mission lifted off from the Xichang Satellite Launch Center in the Sichuan province in the early morning, confirmed by the Twitter account of the country’s state-run Xinhua news agency.

It’s expected to land in early January after 26 days of flight, said China’s Aerospace Science and Technology Corp.

The lander will conduct the first lunar low-frequency radio astronomy experiment, observe whether plants will grow in the low-gravity environment, and explore whether there is water or other resources at the poles.

Another function of the mission is to study the interaction between solar winds and the moon surface using a new rover.




Since the far side of the moon is shielded from electromagnetic interference from the Earth, it’s an ideal place to research the space environment and solar bursts, and the probe can ‘listen’ to the deeper reaches of the cosmos,” said Tongjie Liu, deputy director of the Lunar Exploration and Space Program Center for the China National Space Administration.

Because the far side of the moon is free from interference from radio frequencies, the mission requires a relay satellite to transmit signals that was launched into place this year.

The Chang’e 4 rover is 1.5 meters (5 feet) long and about 1 meter (3.3 feet) wide and tall, with two foldable solar panels and six wheels.

China is anxious to get into the record books with its space achievements,” said Joan Johnson-Freese, a professor at the US Naval War College and an expert on China’s space program.

Beijing plans to launch its first Mars probe around 2020 to carry out orbital and rover exploration, followed by a mission that would include collection of surface samples from the Red Planet.

In comparison, despite its recent success in sending a robotic lander to Mars, the US space agency NASA has faced years of budgetary constraints.

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Pass it on: New Scientist

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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Pass it on: Popular Science

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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Scientists Have Discovered A Bacteria That Eats Microbes That Destroy Ancient Paintings

Organisms that degrade historic works of art (pictured) have been identified through detailed analysis of a 400-year-old painting. The study shows that what can be a feast for the human eye may be a literal feast for microorganisms colonising paintings

Organisms that degrade historic works of art have been identified through detailed analysis of a 400-year-old painting.

The study shows that what can be a feast for the human eye may literally be a feast for microorganisms colonising paintings.

But researchers found that while some microbes destroy such works of art, others might be employed to protect them.

Researchers say the wide variety of organic and inorganic materials that comprise a painting – such as canvas, oil, pigments, and varnish – can provide an ‘ideal environment’ for colonising bacteria and fungi.

This increases the risk of biodegradation.

To find these microorganisms, scientists looked at a piece called ‘Incoronazione della Virgine’ completed by Italian artist Carlo Bononi in 1620.

Dr Elisabetta Caselli and her colleagues from the University of Ferrara removed a 4 mm2 section of the painted surface next to a damaged area.




Using a combination of microscopy and microbial culture techniques, the researchers identified a variety of microbes which had colonised the painting.

They isolated multiple strains of Staphylococcus and Bacillus bacteria as well as filamentous fungi of the Aspergillus, Penicillium, Cladosporium, and Alternaria genera.

The research team noted that some of the 17th Century paint pigments used, notably red lac and red and yellow earths, may be nutrient sources for the microbes.

They also tested a decontaminating biocompound which contained spores of three Bacillus bacteria.

To find these microorganisms, scientists looked at a piece called ‘Incoronazione della Virgine’ completed by Italian artist Carlo Bononi in 1620

They found that they could inhibit growth of both the bacteria and the fungi isolated from the painting.

The researchers concluded that a wide range of bacterial and fungal species may inhabit such ancient paintings but biocompounds potentially represent a new approach for preserving works of art at risk of biodegradation.

Dr Caselli said: “Clarification of biotederioration processes in artworks is important, as it could help in preventing or solving the associated damages.

She added: “This study investigated such aspects in a 17th Century painting, by analysing both microbial communities and chemical composition of painting, also evaluating a possible biological way to counteract these phenomena.

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Pass it on: New Scientist

How To Actually Keep New Year’s Resolutions, According To A Behavioral Scientist

If you plan on becoming a better person in 2015 by exercising more, eating less, or learning a new language, you’re going to need a whole lot more than just good intentions to get you there.

Here’s a little psychological experiment that just might help you stick to your goals.

So, in 2019 we’re all going to go to the gym more regularly, eat better, earn more, and read twice as many books, right?

Wrong – for the majority of us anyway. If you want a good indication for what you’ll be doing in 2019, your best bet is to look at what you did in 2018.

Studies have shown that good intentions alone will only prompt a change in behavior 20 to 30 percent of the time.




In the vast majority of cases, something a little more concrete is going to have to come into play if you want to make a meaningful change to your habits.

So, surprise, surprise, it takes a whole lot more effort to stick to your new year’s resolutions than just writing them down in a fancy list.

And even more discouraging – research has shown that the better we feel about our new year’s resolutions and our ability to stick with them, the less likely we actually will.

But, as Stephen J. Meyer writes at Forbes, it’s not hopeless:

“I’d be a hardened pessimist if not for one thing – there’s a magic bullet that can bridge the gap between goal intentions and goal accomplishment.”

“It’s what behavioural psychologists call “implementation intentions.” Ugly phrase, I know. But it could be the difference between achieving your goals in 2015 and failing miserably.”

So what exactly is this “implementation intentions” concept?

Back in 2002, researchers in the UK gathered together a group of volunteers who had set themselves the goal of taking up regular exercising. The volunteers were split into three groups.

The first group, called the “motivational intervention group”, was given educational materials showing that exercise does amazing things for your cardio-vascular health.

The second group was asked to plan and write down their “implementation intentions”.

For example, exactly where, when, what, they were going to do for exercise, and how frequently, and for how long, each session.

The control group was left to their own with no help from the researchers.

Amazingly, 91 percent of Group 2, who actually thought about and wrote down all the details of their plan, ended up exercising.

According to Meyer, just 29 percent of the control group and 39 percent of the group who learned extensively about the benefits of exercise ended up actually doing it.

So implementation intentions are essentially about fooling ourselves into doing something – you consciously formulate a plan, and then unconsciously execute it.

Gollwitzer mentioned a study in which students were asked to write a paper during the Christmas break.

Of the group that wrote down their implementation intentions – when and where they intended to write their paper – two-thirds of them actually did it.

Exactly zero students who didn’t write their implementation intentions got around to writing the paper.

Apparently similar results can be seen in people trying to lose weight.

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Pass it on: Popular Science