Star clusters are common structures throughout the Universe, each made up of hundreds of thousands of stars all bound together by gravity. This star-filled image, taken with the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 (WFC3), shows one of them: NGC 1866.

NGC 1866 is found at the very edges of the Large Magellanic Cloud, a small galaxy located near to the Milky Way. The cluster was discovered in 1826 by Scottish astronomer James Dunlop, who catalogued thousands of stars and deep-sky objects during his career.

However, NGC 1866 is no ordinary cluster. It is a surprisingly young globular clustersituated close enough to us that its stars can be studied individually — no mean feat given the mammoth distances involved in studying the cosmos! There is still debate over how globular clusters form, but observations such as this have revealed that most of their stars are old and have a low metallicity. In astronomy, ‘metals’ are any elements other than hydrogen and helium; since stars form heavier elements within their core as they carry out nuclear fusion throughout their lifetimes, a low metallicity indicates that a star is very old, as the material from which it formed was not enriched with many heavy elements. It’s possible that the stars within globular clusters are so old that they were actually some of the very first to form after the Big Bang.

In the case of NGC 1866, though, not all stars are the same. Different populations, or generations, of stars are thought to coexist within the cluster. Once the first generation of stars formed, the cluster may have encountered a giant gas cloud that sparked a new wave of star formation and gave rise to a second, younger, generation of stars — explaining why it seems surprisingly youthful.

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We’re barking up the wrong tree if we think plants have no higher sentience, says researcher Monica Gagliano – they just don’t show it like we do.

By Joshua Howgego

MONICA GAGLIANO was diving on Australia’s Great Barrier Reef one day in 2008 when she had an epiphany. She was carrying out ecological experiments on reef fish that required her to kill them afterwards to harvest tissue samples. The fish had been swimming in and out of her hands for weeks. But that day they seemed to be hiding – almost as if they knew.

It was the moment at which Gagliano decided not only never to kill another animal for scientific purposes, but also to devote her research time to the sentience of other life forms. That led her to plants. Since no models existed for studying their behaviour, she applied her existing knowledge. “I looked at them as if they were my animals,” says Gagliano, who is due to take up a post at the University of Sydney this year. The approach has revealed that plants have a surprising range of abilities – and Gagliano is convinced she will discover more.

People often think plants don’t do much. Are they wrong?

The main reason we don’t appreciate them is that they operate at a different pace. It isn’t just a slower pace. Some plants are too fast for us, like the ones that explode to fire out their seeds. Plants also have a different way of manoeuvring in the environment. Animals move from A to B, but plants grow from A to B. They need to detect as much as possible beforehand to avoid growing in the wrong place, so they have very fine-tuned senses. The more we have looked, the more we have realised that they have a suite of behaviours.

What kinds of abilities do they have?

One that might come as a surprise is their acoustic abilities. Plenty of organisms have mechanoreceptors that respond to mechanical forces, and we now know plants have one that can pick up vibrations. Some can even “hear” the vibrations of a caterpillar munching their leaves and strike back by emitting repellent chemicals.

You say plants can learn. Why do you think that?

My idea was to take something that plants might consider a threat and see whether they could learn not to bother about it. Mimosa was a good plant to use because it quickly folds up its leaves when it feels threatened. I created a set-up that allowed me to drop a mimosa from about 15 centimetres high. It sounds terrible! But it actually wasn’t. I put it in a pot and it would slide down a bar onto some foam.

The first couple of times, the plant was like, “What’s happening?” It closed up its leaves. Usually with animals we need to do lots of repetitions before they learn what’s going on. So I was quite surprised that some of my plants started reopening their leaves after two to six drops.

How did other researchers react when you said that plants are good learners?

Plant biologists told me that I’m using the wrong words. But “learning” is exactly what I mean. Whether it is an animal, a plant or bacteria, if it ticks the boxes that we agree define learning, then that is what it is doing.

Does this go beyond the most basic learning?

The next level up is Pavlovian learning. In the famous example of Pavlov’s dogs, the dog learns that the bell always comes before dinner. I tried it with pea plants. The plant’s “dinner” was light and the “bell” was a little fan. I tested the fan first and the plant couldn’t care less about it. It was a meaningless cue, just as the bell was for the dog.

I put the peas in Y-shaped chambers that, once the plants have grown to a certain height, forced them to grow either left or right. I let the fan blow down one arm of the chamber then followed it with light. I did the same for two more days, each day changing the side the fan and light came from.

On the fourth day, I turned on the fan, but not the light. The instinctual response would be for the plant to grow towards the side where light was the day before; plants are good at remembering where they saw light. But would it learn to go against its instinct and follow the fan, which is a precursor of where the light is going to be? That is exactly what the peas did.

How could you tell that plants weren’t just choosing randomly which way to go?

Around 60 per cent of the peas grew towards the fan on the fourth day. That might appear not much more than random, but normally plants always go towards where they saw light last – not just sometimes, 100 per cent of the time. So, if 60 per cent go the other way, that is a high proportion.

You used the word “remember”. Are you saying plants have memories?

Memory is intrinsic to learning. And by the way, the pea wasn’t the first to show that plants have memory. In the mimosa drop experiment, I left my plants for almost a month and then went back to repeat the experiment. The plants responded exactly as if the last drop had been 5 minutes before.

If plants have memories, where are they stored?

The neat thing about plants, and the thing that makes them challenging for us to understand, is that they are totally decentralised. That means memories won’t be in a specific place like the leaves or the roots. The plant functions as a total brain, if we want to put it that way.

Our memories are stored in the brain, in patterns of electrochemical activity. Plants are masters of electrochemical signalling. A lot of electricity and a lot of chemical signals are running through plants. They have the same kind of channels that power our own cells’ electrical signalling and very similar chemicals are involved.

“Plant memories are decentralised – the whole plant is a total brain”

Could we ever see such signals?

If this were an animal, we would challenge it with a task and monitor what is occurring at the electrochemical level. We can plug a human into a machine and see how brain activity changes when they view happy or sad pictures, for example. I am planning to try something similar in plants soon.

Why have we been so slow to appreciate plant abilities?

We assume that humans are the golden template: anything that operates as we do gets a big tick. But that assumption is proving quite bad for the environment. It is also a hypothesis that doesn’t hold because the evidence is showing that the brain isn’t the only thing to produce learning. Plants are revealing that.

This article appeared in print under the headline “The plant whisperer”

This composite image of Earth and Mars was created to allow viewers to gain a better understanding of the relative sizes of the two planets. Image credit: NASA/JPL-Caltech

Mars and Earth are like two siblings who have grown apart.

There was a time when their resemblance was uncanny: Both were warm, wet and shrouded in thick atmospheres. But 3 or 4 billion years ago, these two worlds took different paths.

We may soon know why they went their separate ways. NASA's InSight spacecraft will arrive at the Red Planet on Monday, Nov. 26, and will allow scientists to compare Earth to its rusty sibling like never before.

Click here for the complete story:

By Don Lincoln of CNN

Don Lincoln is a senior scientist at Fermi National Accelerator Laboratory. He is the author of "The Large Hadron Collider: The Extraordinary Story of the Higgs Boson and Other Stuff That Will Blow Your Mind" and produces a series of science education videos. Follow him on Facebook. The opinions expressed in this commentary are his. View more opinion articles on CNN.

(CNN)According to a recent paper, the Earth is caught directly in the crosshairs of a cosmic hurricane. A swarm of nearly 100 stars, accompanied by an even greater amount of dark matter, is aimed directly at our stellar neighborhood and there's nothing we can do to stop it; in fact, the vanguard is already upon us. This sounds like a perfect summer blockbuster movie, starring The Rock and Chris Pratt, or maybe Scarlett Johansson and Charlize Theron.

Don Lincoln

Something is wrong with dark matter

Astronomers identified S1 as being part of the remnants of a dwarf galaxy that collided with the Milky Way and was consumed in an epic episode of cosmic cannibalism. Dwarf galaxies are very small, typically about 1% the mass of the Milky Way. They can orbit larger galaxies and collide with the bigger galaxy, adding their mass to the parent. This is what appears to have happened in the case of S1, although the process has taken probably a billion years.

Dwarf galaxies often have a disproportionately large fraction of dark matter. Dark matter is a hypothetical and still-undiscovered form of matter that interacts only gravitationally. Scientists have proposed its existence to explain many astronomical mysteries, for example the observation that most galaxies rotate faster than can be explained by the known laws of physics and the stars and gas of which they are composed.

While dark matter has not yet been observed, hypothesizing its existence is the simplest and most economical explanation for myriad astronomical mysteries. Averaged over the entire universe, dark matter is thought to be five times more prevalent than the ordinary mass of stars and gas and planets.

In dwarf galaxies, the fraction of dark matter is often higher. In Fornax, a well-studied dwarf galaxy orbiting the Milky Way, researchers estimate that the dark matter is between 10 and 100 times greater than the mass found in its stars.

If that number holds for S1, the dark matter of the S1 stream is passing through the Earth at a much higher velocity than the more ordinary dark matter that orbits the Milky Way -- about twice as fast. It is thought that S1 dark matter is flying through the solar system at a speed of about 550 km/s, or about 1.2 million mph. While these numbers are impressive, they are misleading. Dark matter, if it exists, is extremely diffuse and it will have no discernible effect on the solar system.

The mystery of the early universe's enormous black hole

Because dark matter hasn't been observed yet, these velocity numbers are speculative, although they are strongly supported by a very large body of evidence. However, the prospect of high velocity dark matter flying through the Earth has suggested an opportunity to detect it.

In a paper in the prestigious journal Physical Review D, researcher Ciaran O'Hare and his collaborators calculated the possibilities of discovering dark matter using both existing and proposed dark matter detectors. They considered two varieties of dark matter particles: a very heavy kind called a WIMP (weakly interacting massive particle) and a very light kind called an axion. Because the ultimate nature of dark matter is not known, it is important to be open to all possibilities.

They found that the detectors they evaluated could find WIMPs for certain ranges of the particle mass. However, when they looked at the axion possibility, it appeared the prospects were even better. Because of its light mass and the manner in which an axion would interact with the detector, the apparatus simply has a better chance of seeing the axion. (If axions exist, of course.)

Experiments with names like ADMX, MADMAX and ABRACADABRA are able or will be able to search for the signatures of dark matter proposed in the recent paper. They consist of technologies that are designed to interact with axions in a strong magnetic field and convert them to ordinary microwaves or radio waves that can be easily detected.

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It's important to remember that the S1 stream poses no credible threat to the Earth and humanity. There is no need for an action hero to save us. However, the synergy of science is staggering. A careful catalog of nearby stars has opened the prospect of a better possibility of finding and identifying dark matter, which is one of the great unanswered mysteries of modern physics. It's an amazing time we live in, in which we can study such things.

I'm excited.

In a search for ancient life on Mars, NASA will send its next rover to explore Jezero Crater — the site of a former delta and lake.

The rover, which is scheduled to launch in 2020, is equipped with a drilling system that can collect and store rock samples that contain clues to Mars’s ancient past. Once the samples are cached, NASA hopes to send follow-up missions to retrieve the samples and return them to Earth.

“Getting samples from this lake-delta system will revolutionize how we think about Mars and its ability to harbor life,” said Thomas Zurbuchen, NASA’s associate administrator for science.

Click here for the complete article:

This illustration shows a simulated view of NASA's InSight lander firing retrorockets to slow down as it descends toward the surface of Mars. Image credit: NASA/JPL-Caltech.

Complete article with information on touchdown broadcasts:

Photo: James Leynse/Corbis/Getty Images

Steve LeVine of Axios

The developed world is aging — in the coming decades, the U.S., Europe and nations across Asia will have hundreds of millions more people who are 60 and older.

The big picture: Much of this coming avalanche of senior citizens won't be playing pinochle at retirement homes. Instead, if technology optimists are correct that advanced economies will continue to need massive numbers of workers despite automation, hiring will continue to be tight. Because they have the most experience, older employees are going to be in huge demand and will work a decade and perhaps longer past 65.

Why it matters: Few companies appear to have made the mental shift to accepting that they need to retain and continue to promote older workers rather than letting them go, according to a recent survey.

Neither has public policy caught up with the aging society, which, unless adjustments are made, will swamp programs like Medicare and Social Security.

• Bias runs deep: Across society and business, it's assumed that older workers are less mentally capable, less agile technologically and overall less desirable for hiring and retention than someone younger.
• "Our society should be ageless," Paul Irving, chairman of the Milken Institute Center for the Future of Aging, tells Axios.
• "This is one of the great challenges of the 21st century — everything will change because of this. And the society that gets it right will be the winners," he says.

Irving wrote about the situation in a new piece for the Harvard Business Review.

What's happening:

• The U.S. and other advanced countries are aging: In a little over 15 years, U.S. retirees will outnumber people 18 and under — the first time this has happened in U.S. history.
• And so is the workforce: In just six years, people 55 and older will be 25% of the workforce, double from 12% in 1994.
• They are also shrinking: The population of most advanced countries is falling because of lower birth rates and a falloff in immigration.

These are long-range trends: The aging of American society and the workforce will not reverse after boomers are gone — Gen Xers and millennials will continue the shift once they reach 65.

• One big fact: Keeping older workers on the job is a potential part of the solution to the social system crisis, as they would continue paying into the social security system.

But embracing older workers will create new problems:

• In at least some cases, older workers sticking around could make it harder for young people to move up the career ladder.

Go deeper:

• The 85 to 94-year-old population is booming
• Senior citizens are taking over fast-food jobs
• Gig economy senior citizens are typically handymen and wedding officiants

By Michael Marshall of New Scientist

Did life begin in a world of proteins? It’s a minority view among origin-of-life researchers but it just got a boost. Researchers have built model cells out of nothing but simple proteins, and those cells can host some of the crucial processes of life.

The small compartments within living cells are normally made from lipids, but in 2014, Stefan Schiller of the Albert Ludwig University of Freiburg in Germany and his colleagues made them using proteins instead. “So we asked the question if these ‘organelles’ also represent a plausible prebiotic protocell model,” he says.

Proteins are built from long chains of amino acids. Schiller’s team made simple chains just five amino acids long. There are hundreds of naturally occurring amino acids, but the researchers used only seven kinds in their experiment to keep the approach simple and more likely to have occurred spontaneously on early Earth.

The chains readily clumped together into spherical containers, which the team describe as “protocells”. This happened in pure water and in water with substances dissolved in it or mixed with alcohol.

The protocells survived temperatures up to 100 °C, as well as being mixed with strong acids and alkalis. That implies they could endure “conditions imagined to be present on the early Earth”, says Schiller. The young planet was bombarded with meteorites and may have had a lot of active volcanoes.

Protein protocells provide

The team has also found that the protocells have a number of life-like properties. They can house large molecules over periods of weeks, just as living cells must play host to DNA and other substances. This included phospholipids, which most modern cells are made of. They also found that two protocells can fuse together to form one.

What’s more, the protocells could host two crucial processes. An enzyme that helps DNA molecules to grow longer worked within them, as did the “translation” machinery that builds proteins from amino acids. In both cases, the mechanisms are highly evolved and cannot have been present in the first living organism, but the experiment is evidence that the protein-based protocells are compatible with the underlying processes.

“One can argue that proteins are sufficient to allow for both membrane formation and enclosure of a reaction space, and performing catalytic reactions for self-sustaining purposes and potential division,” says Schiller.

Other researchers have made protocells from lipids such as fatty acids, which are arguably more like modern cells. These protocells also display life-like properties, such as dividing to form “daughter” cells and hosting genetic material. But it is unclear whether any of these artificial protocells could have formed or survived on the early Earth.

Journal reference: bioRxiv, DOI: 10.1101/463356