Higher education levels linked to increased nearsightedness

Myopia - or nearsightedness - is a common condition that affects around 42% of all Americans. Now, new research suggests that higher levels of education and more years spent in school are linked with a greater prevalence and severity of the eye condition.

The research is published in Opthalmology, the journal of the American Academy of Opthalmology.

According to the organization, nearsightedness is a refractive error, whereby the eye does not bend or refract light correctly, causing close objects to look clear but distant objects to appear blurred.

Though the condition is common, the researchers - led by Dr. Alireza Mirshahi of the University Medical Center in Mainz, Germany - say nearsightedness has become even more common around the world recently, making it an increasing global health and economic worry.

For example, in developed Asian countries, myopia rates have increased to nearly 80%, and the researchers say this rapid increase suggests environmental factors may be to blame.

Not only does severe nearsightedness cause visual impairment, but it is also linked with increased risk of retinal detachment, myopic macular degeneration, premature cataracts and glaucoma.

To further investigate the relationship between nearsightedness and environmental factors, the researchers examined 4,658 Germans with myopia who were between the ages of 35-74, after excluding any subjects with cataracts or anyone who had refractive surgery in the past.

Nearsightedness gets worse for every additional year of school

Their work is known as the Gutenberg Health Study and is the first population-based study to show that environmental factors outweigh genetics when it comes to myopia development.

Nearsightedness increases as education levels increase, researchers say.

Overall, their results show that as education level increased, myopia became more prevalent.

In detail, they found that 53% of university graduates were nearsighted, compared with 35% of high school graduates and 24% of subjects without a high school education.

Additionally, the team observed that people who spent more years in school were more myopic, with nearsightedness getting worse for every additional year of school. After looking at the effect of 45 genetic markers, they found them to be a much weaker factor in nearsightedness, compared with education level.

As a result of their findings, Dr. Mirshahi says children and young adults should be encouraged to go outside more often:

"Since students appear to be at a higher risk of nearsightedness, it makes sense to encourage them to spend more time outdoors as a precaution."

Furthermore, the team notes that recent studies of children and young adults in Denmark and Asia have shown that the more time spent outside exposed to daylight, the less the prevalence and severity of nearsightedness.

Just last month, the American Academy of Opthalmology released two new studies that added to the growing evidence that spending time outdoors may help prevent or minimize nearsightedness in children.

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Blood test to indicate breast cancer risk 'in development'

Researchers from University College London in the UK are developing a simple blood test to help predict the likelihood of a woman developing breast cancer. They publish their research in the open access journal Genome Medicine.

The University College London (UCL) team first identified an epigenetic signature that can be detected in the blood of women who have an inherited genetic mutation that predisposes them to breast cancer.

The mutation occurs in the BRCA1 gene and is believed to cause at least 10% of breast cancers. The causes behind the other 90% of cancers are unknown, however. Increasingly, research is shifting from the idea that genetic mutations are the sole contributors to the development of the disease.

Instead, scientists are now investigating how the arrangement and expression of our geness - epigenetics - affects how they function. The subject of the UCL research is a much-studied epigenetic mechanism known as "DNA methylation."

The researchers analyzed blood samples collected from two large UK cohorts of women - the MRC National Survey of Health and Development and the UK Collaborative Trial of Ovarian Cancer Screening. The samples were taken several years before any of the woman had developed cancer.

Comparing the DNA methylation signatures in the blood of the women, the researchers found that the women who developed both hereditary and non-hereditary breast cancer shared the same signature.

As Prof. Martin Widschwendter, study lead author and Head of University College London's Department of Women's Cancer, explains:

"We identified an epigenetic signature in women with a mutated BRCA1 gene that was linked to increased cancer risk and lower survival rates. Surprisingly, we found the same signature in large cohorts of women without the BRCA1 mutation and it was able to predict breast cancer risk several years before diagnosis."

Prof. Widschwendter and colleagues believe that the epigenetic signature may be responsible for silencing genes in immune cells. If these genes are silenced, then the immune system may be less able to prevent the development of breast cancer.

More research is needed to confirm whether the signature is an indicator of breast cancer risk or whether it is involved in the progression of the disease.

However, more research is needed to confirm whether the signature is an indicator of breast cancer risk or whether it is involved in the progression of the disease.

"The data is encouraging," Prof. Widschwendter concludes, "since it shows the potential of a blood-based epigenetic test to identify breast cancer risk in women without known predisposing genetic mutations."

Earlier this week, Medical News Today reported on a study published in JAMA that found the addition oftomosynthesis, a 3D imaging technique, to digital mammography improves breast cancer detection rates.

Also, a recent study published in PLOS Medicine explored using skin moles as a predictor of breast cancer. The researchers behind that study had observed that moles become bigger or darker during pregnancy, and so wondered if there was an association between elevated hormone levels and moles that might also influence breast cancer development.

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Some acne products can cause serious allergic reactions, FDA warns

The Food and Drug Administration are warning consumers who use certain over-the-counter skin products for acne to stop using them and seek emergency medical help immediately if they experience extreme allergic reactions such as feeling faint, breathing difficulties, throat tightness or swelling of the eyes, lips, face or tongue.

Consumers should also stop using the products if they develophives or itching, say the Food and Drug Administration (FDA), who have issued a Drug Safety Announcement and accompanying Consumer Update about topical acne products that contain the active ingredients benzoyl peroxide or salicylic acid.

The over-the-counter (OTC) acne products the FDA is warning about already include a list of reactions in the Drug Facts labels namely: itching, peeling, redness, burning, dryness and slight swelling where the product is applied.

However, the new FDA warning is about rare but serious and potentially life-threatening allergic reactions or severe irritation that are not among the already listed reactions, as Dr. Mona Khurana, a medical officer with the FDA, explains:

"There is currently no mention of the possibility of these very severe allergic reactions on the product labels. It's important that consumers know about them and that they know what to do if they occur."

To find out if an OTC acne product contains the active ingredients benzoyl peroxide or salicylic acid consumers should look at the Active Ingredients section of the Drug Facts label on the product package.

Products containing the active ingredients benzoyl peroxide or salicylic acid are available in a number of skin applications, such as face washes, solutions, cleansing pads, gels, lotions, toners, face scrubs and other products.

They are sold under various brand names, including: Ambi, Aveeno, Clean & Clear, MaxClarity, Neutrogena, Oxy and Proactiv.

Not clear if active ingredients are to blame

The FDA say that between 1969 to early 2013, they received 131 reports from consumers and manufacturers about allergic and hypersensitivity-related reactions linked to these products. The people affected were between 11 and 78 years old. The federal agency notes that:

"Based on the information reported to FDA, we cannot determine if the serious hypersensitivity reactions were triggered by the acne products' active ingredients, benzoyl peroxide or salicylic acid, the inactive ingredients, or by a combination of both."

The FDA report that 42% of the reactions occurred within minutes to 24 hours of using the product.

Consumers should stop using skin products if they develop hives or itching, say the FDA.

No deaths have been reported, but nearly half (44%) of the cases required hospitalization.

Dr. Khuruna says the FDA will continue to monitor and evaluate the safety of the products and is encouraging the companies that make them to use the drug label to inform consumers how to test if the product is safe before they begin to use it.

The FDA advice is to apply a small amount to a small area of affected skin for 3 days - if there is no discomfort or reaction, then it is alright to go ahead and follow the instructions for normal use given on the product label.

The FDA urges consumers who have bad reactions or side effects to report them to MedWatch, the FDA Safety Information and Adverse Event Reporting Program.

In August 2013, the FDA issued a warning about rare but serious skin reactions from taking acetaminophen, one of the most commonly available and long-used drugs for relieving pain and reducing fever.

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Rafael Nadal survives scare against Lukas Rosol at Wimbledon

World number one Rafael Nadal fought back to beat Lukas Rosol and avoid a repeat of his shock Wimbledon defeat by the unseeded Czech two years ago.

Rosol, ranked 52nd, had a set point for a two-set lead, but two-time champion Nadal recovered brilliantly to come through 4-6 7-6 (8-6) 6-4 6-4.

The Spaniard, seeded second, goes on to face Mikhail Kukushkin of Kazakhstan in the last 32 on Saturday.

It is the first time since 2011 that Nadal has reached the third round.

"I knew I had to keep fighting, waiting for my moment," Nadal told BBC Sport.

"I made a few mistakes but he was serving very well, then the second set was very important. Against Rosol, two sets down, it would have been very dangerous."

If Rosol's second-round victory over Nadal in 2012 was one of the greatest upsets in tennis history, repeating the effort seemed even more unlikely. Yet the Czech went closer than anyone could have expected.

Once again, the 28-year-old found a rich seam of heavy serving and thunderous groundstrokes that left Nadal helpless and facing a two-set deficit.

After breaking at 4-4 on his way to taking the first set, Rosol moved 4-2 clear in the second as the winners flew off his racquet behind an impenetrable serve.

Nadal looked forlorn and his coach and uncle, Toni, stood and urged on his nephew from the players' box.

Finally, Rosol gave the 14-time Grand Slam champion some breathing space as the Czech's first serve faltered and Nadal took advantage with some fine returning to get back on level terms and force the tie-break.

John McEnroe on Nadal's win
"How do you teach will, desire, not to quit in any circumstances? you don't see this often, once every 10 years if you're lucky. Nadal has made other guys better trying to compete with him. In the definition of 'where there's a will there's a way' he's the picture you're going to see."

Another surge of adrenaline saw Rosol hammer a forehand to edge 5-3 ahead, but with two serves for a two-set lead Nadal pegged him back with a low slice, and facing set point the Spaniard backed up his serve with a trademark forehand winner.

Rosol had won just two Grand Slam matches since his 2012 win over Nadal, and the difference in big-match experience suddenly came to the fore.

Nadal was now the one up on his toes and Rosol on the defensive, double-faulting when facing set point and fading further as the pressure only grew from his opponent.

Rosol hit 22 winners in the second set but could not keep up that level in the third and fourth sets

The Czech fought off three break points before netting a forehand to drop serve early in the fourth, and Nadal moved confidently towards the finish line before one late scare.

Rosol remained a threat and a mistimed forehand from the Spaniard at 30-30 when serving for the match offered up one last sliver of hope, but Nadal responded with a forehand winner before converting his second match point.

"I never play for revenge, every match is a different match," added Nadal. "Today was another match I tried to win.

"It's a great win for me. It's the best level I played on grass since a long time ago, the last three sets. That's very important news for me."

Rosol said: "I was not thinking if I can do it again, if I can not do it again. I was trying to just play my game, concentrate every single point, and from the beginning was pretty good, everything was working.

"Third and fourth sets I was really struggling on my serve. Not many first serves in. Without serve then we start to play rallies, and that was his game."

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Cristiano Ronaldo's second-half winner gave Portugal a 2-1 victory over Ghana, but the result means that neither team progress to the World Cup's last 16.

Ghana defender John Boye gifted Portugal the lead when he turned a cross into his own net, but Asamoah Gyan headed in an equaliser.

Ronaldo capitalised on a poor clearance to sweep home and give Portugal hope.

But they could not find the three more goals they needed to prevent the United States advancing on goal difference.

Analysis

Former Scotland international Pat NevinBBC Radio 5 live

"Both sides had chances to go through, and they can't blame anyone else but themselves. Cristiano Ronaldo missed six golden opportunities, and should have had a penalty as well. He didn't look fully fit to me.

"A fully-fit Ronaldo could have torn this tournament apart. I don't think Ghana have enough quality going forward; they're far too reliant on Asamoah Gyan."

The USA lost to Group G winners Germany 1-0 in the section's other game.

Ronaldo's goal was his first in what was ultimately a disappointing tournament for a player who had scored 51 times in 47 appearances for Real Madrid last season.

The 29-year-old, who has suffered from knee and thigh injuries, failed to replicate the influence he had at club level as Portugallost heavily in their opening group game against Germany, before a draw with USAleft them needing to win by a large scoreline against Ghana to progress.

Ronaldo was given the freedom to roam across the Portugal frontline against the African side and, initially, he was at the centre of their best chances.

First, he almost caught out scrambling Ghana goalkeeper Fatawu Dauda with an audacious chip that smacked the crossbar, before his close-range header from Joao Pereira's pinpoint cross was instinctively batted away by Dauda, who turned and roared in delight at the Ghana fans behind his goal.

His joy, though, was short-lived, as Ghana conceded an unfortunate opener midway through the half.

Joao Moutinho fed Miguel Veloso on the left and he delivered a teasing cross that Ghana centre-back Boye deflected into the top corner of his own goal with his thigh.

While Portugal's problems have solely been on the pitch, Ghana's preparations were hampered by chaos behind the scene.

Midfielders Sulley Muntari and Kevin-Prince Boateng were expelled from the squad for alleged indiscipline - although Muntari would have missed the Portugal game anyway through suspension after picking up yellow cards in their first two games - while players had even threatened to boycott the Portugal fixture because of a row over appearance fees.

Match facts
Portugal won for only the second time in their last 10 World Cup matches
Asamoah Gyan (six) became the outright leading African World Cup scorer, going clear of Roger Milla
This match contained 35 shots (including blocked efforts). Only four matches in this tournament have contained more

That was resolved on Wednesday and the Ghana players looked to have put it behind them as they pressed for an equaliser, only for wayward finishing from Christian Atsu and Gyan to prove their undoing.

For all their enterprising build-up play, it seemed Ghana would need a moment of magic to get back into the game.

That arrived just before the hour as Kwadwo Asamoah curled a stunning cross with the outside of his boot towards the far post, where Gyan was on hand to plant a header into the net.

With Germany leading the USA at the time, qualification suddenly became a realistic possibility for Ghana and they came agonisingly close to securing the win they needed when Majeed Waris flicked a header just wide from Gyan's cross.

However, Dauda ended his own side's hopes of securing victory when he pawed at a Portugal cross, clearing only as far as Ronaldo, who made no mistake.

Portugal coach Paulo Bento:

"It's not fair to blame individuals. We made mistakes as a team in the three matches - and I will never hold any individual responsible. We win and lose as a team.

"It's a tough time for us and we feel down as we all wanted to qualify for the Round of 16. We must now grow and advance so that we don't feel the same in 2016."

Portugal forward Cristiano Ronaldo:

"We created many opportunities but we could not finish them all. We knew we had to score three goals and we were depending on the result of the Germany game.

"We knew it was complicated but what's left at the end shows that it was possible considering the number of opportunities we created during the game."

Ghana coach Kwesi Appiah:

"It was a very exciting match with many chances on both sides.

"Unfortunately we didn't take ours and they took theirs."

John Boye's own goal was the fourth of this tournament. There were only two in the 2010 World Cup

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Formula 1: standing re-starts after safety car to be introduced

Formula 1 is to introduce standing re-starts following a safety-car period from next season.

The move, intended to make place changes more likely at a re-start, is one of a series of rule changes introduced by governing body the FIA.

Among them, the rules on noses will be changed to prevent the'anteater' noses that predominate this season.

Driver reaction to the re-start change was mixed when news of the plan leaked at last weekend's Austrian Grand Prix.

Ferrari's Fernando Alonso said he had no strong opinions, while championship leader Nico Rosberg said it was "extreme".

The Mercedes driver added: "I understand the start is one of the most exciting times for the fans but it sounds very extreme so I hope it's not going to be done.

"It's going too far with things. I don't want to see such a huge change to do another start."

F1 bosses feel that the current rolling starts behind a safety car do not provide sufficient excitement, because there is almost never any overtaking. A standing start increases the chances of drivers gaining or losing positions.

The safety car will be retained to control the pace of the field while any accident damage is cleared because it provides a commercial benefit to F1 - Mercedes pay to provide the safety and medical cars.

Red Bull's Daniel Ricciardo, who won this month's Canadian Grand Prix after a safety-car period, said: "Maybe (it will) be more exciting because there is a bit more variability.

"But to me that's a bit too artificial because if you're a leader, say by 10 seconds, the safety car comes out, OK you lose your advantage, but at least you can still keep your position.

"If it goes to a standing start, the chances of not-a-great start are pretty high so you could go from first to even fourth.

"It's just a bit too much of a disadvantage for someone who earned the lead in the first place.

"Now rolling starts are not too bad, at least it bunches everyone up. For spectators, a standing start would be better, yeah, but probably not the most fair idea."

Others rule changes include tweaks to the number of tests and reductions in the allowed amount of research and development, both aimed at cutting costs.

The three pre-season tests will have to take place in Europe, whereas until now teams could test further afield, and the number of in-season tests will be reduced from four two-day tests to two.

Two of the permitted four days must be reserved for drivers with limited experience of F1, in order to make it easier the next generation of drivers.

Among other cost-cutting plans, teams will be allowed to use only four engines per season, down from the current five, unless there are more than 20 races.

The FIA said the changes to the nose rules would "ensure improved safety and provide more aesthetically pleasing structures".

Many of this year's cars have narrow protuberances forward of the main nose structure to satisfy rules that were aimed at making the noses lower for safety reasons but in which teams found loopholes.

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thomas muller curls Germany into lead aver USA

Story of the match:

• Torrential rain in Recife means many fans miss kick off
• Thomas Muller scores his fourth goal of the tournament to give Germany the win
• Germany go through as Group G winners
• The US through as runners-up and will face Belgium in the last 16

Thomas Muller once again made the difference as Germany qualified as winners of Group G with victory over the United States, who also reached the last 16 at the World Cup.

The Bayern Munich forward scored his ninth World Cup goal in as many games to give Germany a routine win at a rain-soaked Arena Pernambuco in Recife.

The rate at which Muller is scoring in World Cup games is matched only by Brazil legend Pele, who also found the net nine times in his first nine matches in the tournament.

The 24-year-old German is now just six goals behind the all-time scoring record, which is jointly held by Muller's team-mate Miroslav Klose and former Brazilian striker Ronaldo.

This was a frustrating afternoon for the United States and their travelling army of fans. They failed to force Germany goalkeeper Manuel Neuer to make a save of note but their qualification was assured by Portugal's 2-1 victory over Ghana in Brasilia.

The US will now travel to Salvador to take on the much-fancied Belgians on Tuesday. Germany will play the runners up of Group H in Porto Alegre on Monday.

Before the game, much had been made of the suggestion that both sides might play for a convenient draw that would take each of them through. But with US coach Jurgen Klinsmann, who previously managed Germany, facing off against his protege Joachim Low, neither team took a backward step from the first whistle.

Germany, playing their familiar passing game at a patient tempo, carved out a series of early chances.

Match facts
Benedikt Howedes received Germany's first yellow card of the tournament. Germany are the last team to receive a booking in this World Cup.
Eight German players attempted more passes in this match than Michael Bradley's 50 - the most by an American player.
Thomas Muller has been involved in 13 of Germany's last 23 World Cup goals.

On three occasions Bayern Munich defender Jerome Boateng found space wide on the right flank and fizzed fierce low crosses into the penalty area, while Arsenal's Mesut Ozil came closest to scoring, stepping away from Matt Besler's challenge to test United States goalkeeper Tim Howard.

Germany had to wait until the 55th minute to make the breakthrough, however, having seen Ozil and substitute Miroslav Klose go close.

It was a cross by the former that created the goal with Arsenal team-mate Per Mertesacker heading powerfully at goal and forcing Howard to push the ball into the path of Muller.

Analysis

Brad FriedelTottenham and former USA goalkeeper

It is an unbelievable day for US soccer. They were not outstanding on the pitch today but they will always give 100% and be organised. The people back home will love this - we've finished above one of the best teams in the world and Portugal and Cristiano Ronaldo are going home. The next game is going to be a massive occasion.

The forward struck his shot first time and it flashed beyond Howard before he could react to put Germany ahead.

The United States did show spells that suggest they will not be easy to beat in this tournament. Michael Bradley was at the heart of their best work, setting the tone with his tenacity in the tackle and his ability to keep possession under intense pressure.

The Toronto midfielder created the USA's best chance of the game, finding Kansas City forward Graham Zusi, whose shot curled narrowly over the bar, but Bradley's touch let him down just as a shooting opportunity presented itself moments before half-time.

The midfielder allowed his frustrations to get the better of him as he caught Muller with his studs raised and was fortunate to escape a booking.

After half-time the USA improved. Alejandro Bedoya saw a shot blocked after a fluent move down the USA right, while Clint Dempsey headed just over late on.

And although Germany closed out the game, when the result was confirmed in Brasilia, the United States also had something to celebrate.

USA coach Jurgen Klinsmann: "It's huge for us to reach the last 16. We wanted at least a tie out of the game and maybe at the beginning we had too much respect.

"But overall there was tremendous energy and effort from all of the side. It's huge for us to get out of group - everyone said we had no chance but we took that chance. Now we want to prove a point."

Germany coach Joachim Low: "I knew it would be difficult today and it was. USA defended deep, they were well organised, but I have to say we dominated, denying them good chances in the process.

"Our midfield was great today - they were dynamic and never stopped running.

"It wasn't easy for USA - everyone thought Portugal would qualify, but they've done it. They're tough opponents and they've deserved it."

Germany forward Thomas Muller: "We were dominant. All the Americans did was sit back deep in their own half, and when that happens, it just becomes a patience game.

"But sometimes even I manage to have a bright idea - I spend the whole day training like I'm obsessed anyway."

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Q&A: The 5 Ingredients Needed for Life Beyond Earth

A NASA scientist lists the essentials that extraterrestrial life must have to exist.

Newly discovered exoplanet GJ 504b, illustrated here, has about four times the mass of Jupiter, making it the planet with the lowest mass directly imaged around a sunlike star.

ILLUSTRATION BY NASA'S GODDARD SPACE FLIGHT CENTER/S. WIESSINGER

Mike Lemonick

for National Geographic

PUBLISHED JUNE 25, 2014

Back when astrogeophysicist Christopher McKay got his doctorate in 1982, the hunt for extraterrestrial life was confined to the solar system. The obvious places to look were the planets and moons that seemed most likely to be habitable: Mars, two moons of Saturn (Enceladus and Titan), and a moon of Jupiter called Europa.

That started to change in 1995, says McKay, a senior scientist at the NASA Ames Research Center, when astronomers began finding planets orbiting distant stars. These so-called exoplanets now number nearly 1,800, with one of the most Earth-like, the planetKepler 186-f that orbits a red dwarf star known as Kepler 186, announced just this past April.

In a recent issue of the Proceedings of the National Academy of Sciences, McKay summarizes how the search for habitable planets needs to go beyond simply looking in the "Goldilocks zone"—the orbital distance where it's not too hot, not too cold, but just right for biology.

National Geographic spoke with McKay about how scientists can tell if an exoplanet is likely to be habitable, based on what is known about the range of environments that can support life on Earth.

In your PNAS paper, you talk about a "checklist for speculating on the possibilities of life on these distant worlds." What's on the list?

The first thing is temperature [i.e., temperature allowing for water in liquid form]. The astronomers know this—it's what defines the "habitable zone." But the next question you need to ask is whether water is actually present.

How do you determine whether a planet not only can have water, but does have water?

We need to have some measurement of the atmosphere to confirm that this isn't a planet that's lost all its water. You don't need much: One of the lessons of life on Earth is that a little water goes a long way. It's nice to have a Pacific Ocean, but you don't need it.

Once you know there's still some water on the planet, what do you need to know next?

Energy sources. Life on Earth uses only two types of energy for metabolism: sunlight and redox chemistry ... One or the other has to be present, and if you're in the habitable zone of a star, you at least have enough light to support photosynthesis.

So you have the right temperature, water, and sunlight. What else do you need?

The next criterion is sort of a negative: Make sure there's nothing that will kill you, such as radiation.

That could be a real problem with a planet like Kepler 186-f, right? It orbits a red dwarf star, and those tend to have a lot of solar flares.

It's true that we humans are cream puffs when it comes to radiation. You know, a little excess sunlight and we get sunburns and skin cancer. But microbes, which are likely to be the first life-forms we find, are much, much tougher with respect to both UV and ionizing radiation.

You also list nitrogen as essential for habitability.

Yes, because life is almost certainly going to use amino acids, and it needs nitrogen to build them. So that's a key requirement.

OK, temperature, water, sunlight, nitrogen, and nothing that will kill off life. Anything else?

Yes: oxygen. It's not evidence of life directly—it's not the same as seeing the life-forms themselves. It's like seeing tire tracks when you're lost in the desert. It's not the car. It's not proof you're about to be rescued. But it's certainly damn interesting. And if the oxygen level is high enough, our experience on Earth leads us to suggest that that should enable complex life, plants and animals. And that's very cool.

So can we go out and search today for the things on your list?

Well, not with any [equipment] that's in space right now. None of the telescopes on the ground right now will do it either, I don't think. But there's no reason why everything on this list couldn't be checked off for Kepler 186-f and other Earth-size planets in the habitable zones of their stars within the next decade.

How about Mars? Is it even still worth looking for life there?

I have to admit my hope is dimming with the results that have come back from Curiosity and other missions. But it's not gone yet, partly because Mars is so close by that it [would] take a lot of negativity before I give up. It's like searching for your keys under the lamppost—you look there because that's where the light is good.

Even if we find life on Mars, though, there's another problem: The first assumption I would make is that, yeah, that's life, but it's directly related to us [because Earth and Mars are so close, any life found on Mars might have originated on Earth and been carried over on a meteorite—or vice versa, that life on Earth might have been carried over from Mars]. You'd have to prove that it isn't. If we find it 500 light-years away, on the other hand, we know it's not related.

You're still working on the search for life inside the solar system, though.

Yes, I'm working on a Europa mission concept, I'm working on an Enceladus mission concept, and I'm working on some Titan mission concepts. I'm working on Mars data coming back right now, and I'm working on future Mars missions. And now I've got a student who's going to be looking at Kepler 186-f, too. So I'm involved with all five of those worlds. I'm like a parent with many children. I love them all, and I resist saying that one is better than the other.

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Triple Monster Black Hole Discovered

Sometimes big, bad things comes in threes, including jumbo black holes.

The new study suggests that many galaxies have not one black hole (as in the illustration above), but two or more giant black holes in their centers.

PHOTOGRAPH BY NASA/CXC/UCLA/Z.LI AND NRAO/VLA

Michael Lemonick

for National Geographic

PUBLISHED JUNE 25, 2014

The discovery of a trio of jumbo black holes circling the center of a distant galaxy, reported by astronomers on Wednesday, suggests that pairs or triplets of such monsters may be surprisingly common.

Astronomers have learned over the past decade or two that virtually every full-size galaxy such as our own Milky Way has a giant black hole lurking in its core. These monsters weigh in with a mass equal to millions or even billions of stars. (Related: "Black Hole: Star Eater.")

The new observations, however, described in the journal Nature, suggest that many galaxies have not one, but two or more giant black holes in their centers, orbiting each other in a tight gravitational dance that will ultimately lead the objects to merge together into something even more gigantic.

Watching these mergers will offer insight into how gravity behaves when stretched to its limits, astronomers predict, with clues revealed by monster black hole mash-ups such as the just-discovered triplet. (See: "Photo Gallery: Black Holes.")

"We were quite surprised to find it," says Roger Deane, of the University of Cape Town in South Africa, lead author of the report.

Supermassive Neighbors

In one sense, Deane and his colleagues shouldn't have been surprised. It's widely accepted that when galaxies come close together, their gravity can force them to form a single agglomeration of stars. In fact, the Milky Way and the (relatively) nearby Andromeda galaxy will probably experience such a merger in about four billion years. Since each galaxy hosts a single massive black hole, the resulting single galaxy should end up with two.

In practice, however, astronomers haven't found many double black holes. One popular explanation has been that the black holes fuse together very quickly, leaving few doubles for astronomers to find. Another explanation, says Princeton astrophysicist Jenny Greene, who wasn't involved with this research, is that they orbit each other so closely that they're hard to pick out.

"In principle," she says, "there could be a huge population of binary black holes separated by just a few light-years."

Invisible Whirlpools

Deane and his group originally became interested in this particular galaxy, known by the unwieldy name SDSS J150243.091111557.3, because it had been flagged by the Sloan Digital Sky Survey (thus the "SDSS" in the name) as having what looked like two sources of bright light in its core.

That indicated the possibility of two black holes there, with the light coming not from the invisible objects themselves but from the whirlpools of gas heated to incandescence as they spiral in under the black holes' intense gravity. Jets emitted by the black holes pinpointed their location.

Seeing black holes

Astronomers detect signals from supermassive black holes by observing jets emitted by these galactic monsters.

JASON TREAT, NG STAFF. SOURCE: ROGER DEANE, UNIVERSITY OF CAPE TOWN.

To try to understand what they were looking at, the astronomers observed the galaxy with the Very Long Baseline Array, or VLBA, which combines images from a score of radio telescopes located in South Africa, Europe, the U.S., Russia, and China. The telescopes' wide geographical separation allowed the scientists to view the galaxy and its patch of sky with extremely high resolution.

Sure enough, they found two black holes, separated by several thousand light-years.

But they also discovered that one of them was actually two jumbo black holes, orbiting so tightly that they had appeared to be a single object. The tight pair, Greene says, "is so sexy is because we really don't know whether black holes ultimately merge."

Chains of Gravity

Theory suggests that they might not, or at least not for many billions of years. The two tightly bound black holes are only 460 light-years apart, orbiting each other once every 150,000 years.

In order to spiral into each other, black holes have to jettison some of their orbital energy. One way to do that is by flinging away nearby stars or gas.

After a certain point, however, there aren't any more stars in their neighborhood to fling: The only way they can get rid of energy is by radiating it away in the form of gravitational waves, a phenomenon predicted by Einstein but never directly observed.

Those waves would become more violent as the black holes came very close to each other, making them detectable in principle by a space-based gravitational-wave detector known as the Laser Interferometer Space Antenna, or LISA, which has been proposed but not yet funded.

"If we can get an idea of what fraction of galaxies have [tightly orbiting black holes]," says Greene, "we can start to constrain how likely it is that LISA will detect gravitational waves."

The good news is that Deane and his colleagues found their one tight pair after looking at just six galaxies. While the pair isn't orbiting closely enough to be picked up by LISA, its discovery suggests that there could be plenty of much tighter pairs out there as well, he says. "Either these are a lot more common than previously thought—or we just happened to be incredibly lucky."

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