In a movie captured by a NASA satellite today, a comet is seen hurtling toward the sun. And just as the streaking icy object is making its final death plunge, the sun lets loose with an explosion of many millions of tons of material from its outer atmosphere.

To the casual eye, it might appear that the comet crashed into the sun, triggering the coronal mass ejection, or CME. That’s exactly what I thought when I watched the movie.

To check it out for yourself, first have a look at the screenshot at the top of this page. Note the starting position of the comet at lower right. (Also note that the bright disk of the sun is blacked out so details won’t be overshadowed.)

Now, click on the image to watch the movie, which consists of images captured by NASA’s SOHO spacecraft starting yesterday (UTC) and continuing into today.

What do you see?

The comet plunges toward the sun, and just when it disappears at the black disk, a bright eruption of material takes place.

Cause and effect, right?

Well, I knew that looks could be deceiving. So I used Twitter to ask some solar experts whether the comet had crashed into the sun, causing a CME. Below is the response I got from the Solar Physics Department of the U.S. Naval Research Laboratory, home of a comet program:

I’ve had black holes on the brain lately.* There’s been a flurry of related research announced lately, even the discovery of black hole-like vortexes in the Atlantic Ocean, and astronomers are keenly watching as a gas cloud is ripped apart by the monster black hole at the center of our galaxy. All of which has prompted me to think about the odd simplicity of how black holes work.

The irony is that black holes are also among the most puzzling objects in the universe, because theorists understand so little about their insides. What happens to the information that is lost when objects fall across the event horizon? What happens to the laws of physics at the singularity in the center? Can black holes create wormholes across space and time? Those internal oddities are so incomprehensible that Albert Einstein did not believe that black holes were a real physical possibility. Which makes it a little confusing to read articles about how Einstein might have been wrong about how black holes work, since he didn’t think they worked at all.

But on the outside, mass, spin, and charge tell you everything there is to observe about a black hole. Practically speaking, most black holes probably have very little net charge, so you could plausibly pare the list to mass and rotation. Even rotation has little impact if you are considering a black hole from a great distance–which, for your sake, I certainly hope you are. Viewed from afar, then, a black hole is a one-attribute object. Mass is the one and only thing you need to know.

Which brings me to another profoundly strange and simple thing about black holes. For an ordinary sphere–a bowling ball, for example–the mass increases as the cube of the radius. If one bowling ball is twice the diameter of another it will weigh eight times (2 cubed) as much. The rule breaks down a bit for large objects like planets, but in a very straightforward way. Their incredible bulk compresses their insides, so as planets get more massive their interiors tend to get more dense, assuming you are making an apples-to-apples comparison of the same type of planet. Some planets around other stars have masses several times that of Jupiter, but they are similar in size because of this gravitational squishing.

Black holes do something completely different, however. Their radius increases in direct proportion to the mass. Double the mass of a black hole, and its diameter doubles as well. (I’m using the event horizon–the point-of-no-return that defines the shape of the black hole–as its “surface” in this discussion.) The math of calculating the diameter of a black hole could not be easier. A black hole with the mass of the sun has a diameter of about 6 kilometers, or 4 miles. Want to know the diameter of the black hole at the center of the Milky Way? Based on the motions of stars circling around it, the black hole has a mass of 3.6 million suns. Just multiply 4 x 3.6 million and you’ve got your answer: It is 14 million miles wide.

The direct relationship between size and mass has a funny effect. The more massive a black hole is, the less dense it is–and the dropoff happens rapidly, as the square of the radius. (Again, I’m using the event horizon to define the surface of the black hole.) A solar-mass black hole crams the sun’s entire 865,000-mile-wide bulk into that 4-mile wide sphere, corresponding to a density 18 quadrillion times the density of water. It’s a staggering number. The black hole at the center of the Milky Way has a mass of 3.6 million suns, which means its density is (3.6 million x 3.6 million) times lower. That translates to about 1,400 times the density of water–still very high, and more than 100 times the density of lead, but no longer so incomprehensible.

Other black holes are much more massive than the central one in our galaxy, though, which means they are also much puffier. The galaxy M87 contains a monster black hole that astronomers have measured as having the mass of 6.6 billion suns. Its density is about 1/3,000th the density of water. That is similar to the density of the air you are breathing right now!

Now to the most mind-blowing part. If you keep going to higher masses, the radius of the black hole keeps growing and the density keeps shrinking. Let’s examine the most extreme case: What is the radius of a black hole with the mass of the entire visible universe? Turns out that its radius is…the same as the radius of the visible universe. Almost as if the entire universe is just one huge black hole.

Want to know what life looks like inside a black hole? Look around. You’re soaking in it.

* If you ask my wife she’ll tell you I’ve had black holes on the brain for at least as long as we’ve been married, but that’s a whole other story.

The apple of Newton's eye and the focus of Einstein's work, gravity is weaker than you probably think and weirder than you probably imagined.

1. Star Wars' Obi-Wan Kenobi said the Force “surrounds us and penetrates us; it binds the galaxy together.” He could have been talking about gravity. Its attractive properties literally bind the galaxy together, but it also “penetrates” us, extending physically through us, keeping us bound to Earth. 

2. Unlike the Force, with its dark and light sides, gravity has no duality; it only attracts, never repels. 

3. NASA is trying to develop tractor beams that could move physical objects, creating an attractive force that would trump gravity. 

4. Passengers on amusement park rides and the International Space Station experience microgravity — incorrectly known as zero gravity — because they fall at the same speed as the vehicles. 

5. Someone who weighs 150 pounds on Earth would — if it were possible to stand on Jupiter — weigh a whopping 354 pounds on the enormous gas giant. Larger masses have greater gravity. 

6. To leave Earth’s gravitational pull behind, an object must travel 7 miles a second, our planet’s escape velocity. 

7. Gravity is by far the weakest of the four fundamental forces. The other three are electromagnetism; weak nuclear force, which governs how atoms decay; and strong nuclear force, which holds atomic nuclei together.

8. A dime-size magnet has enough electromagnetic force to overcome all of Earth’s gravity and stick to the fridge. 

9. An apple didn't hit Isaac Newton in the head, but it did make him wonder if the force that makes apples fall influences the moon’s motion around Earth. 

10. The apple in Newton’s eye led to the first inverse square law in science, F = G * (mM)/r2. This means an object twice as far away exerts a quarter of the gravitational pull. 

11. Gravity’s inverse square law also means the reach of gravitational attraction is technically infinite. Whoa.

12. Gravity’s other definition — meaning something weighty or serious — came first, originating from the Latin gravis, or “heavy.” 

13. The force of gravity accelerates everything at the same rate, regardless of weight. If you dropped balls of the same size but different weights from a rooftop, they would hit the ground at the same time. The heavier object’s greater inertia cancels out any speed it might have over the lighter object. 

14. Einstein’s general theory of relativity was the first to treat gravity as a distortion of space-time, the “fabric” that physically embodies the universe. 

15. Anything with mass warps the space-time surrounding it. In 2011, NASA’s Gravity Probe B experiment showed Earth tugs on the universe around it like a wooden ball spinning in molasses, exactly as Einstein predicted. 

16. When distorting the space-time around it, a massive object sometimes redirects light that passes through it, just as a glass lens does. Gravitational lensing can effectively magnify a distant galaxy or smear its light into a strange shape. 

17. The “Three-Body Problem,” determining all the patterns three objects orbiting each other could take if influenced only by gravity, has puzzled physicists for 300 years. So far they’ve found only 16 types of solutions — 13 of them just discovered this March. 

18. Although the other three fundamental forces play nice with quantum mechanics — the science of the very small — gravity is stubbornly incompatible with it; quantum equations break down if they try to include gravity. How to reconcile these two completely accurate but opposing descriptions of the universe is one of physics’ biggest questions. 

19. To understand gravity better, scientists are looking for gravitational waves, ripples in space-time that result from things like black holes colliding and stars exploding, according to Amber Stuver, a physicist at Louisiana’s Laser Interferometer Gravitational-Wave Observatory (LIGO). 

20. Once LIGO researchers successfully detect gravitational waves, they’ll be able to use them to see the cosmos as never before. “Every time we’ve looked at the universe in a new way,” Stuver says, “it revolutionized our understanding of the universe.” Talk about heavy.

Cognitive behavioural therapy (CBT) is a type of talking therapy that's used to treat a wide range of mental health problems, from depression and eating disorders to phobias and obsessive-compulsive disorder (OCD). It recommends looking at ourselves in a different way that might prove useful for all of us in everyday life. But what happens to our brains when we have CBT?

What is cognitive behavioural therapy?

CBT is based on the idea that problems aren't caused by situations themselves, but by how we interpret them in our thoughts. These can then affect our feelings and actions.

For example, if someone you know walks by without saying hello, what's your reaction?

You might think that they ignored you because they don't like you, which might make you feel rejected. So you might be tempted to avoid them the next time you meet. This could breed more bad feeling between you both and more "rejections", until eventually you believe that you must be unlikeable. If this happened with enough people, you could start to withdraw socially.

But how well did you interpret the situation in the first place?

CBT aims to break negative vicious cycles by identifying unhelpful ways of reacting that creep into our thinking.

"Emotional reasoning is a very common error in people's thinking," explains Dr Jennifer Wild, Consultant Clinical Psychologist from Kings College London. "That's when you think something must be true because of how you feel."

CBT tries to replace these negative thinking styles with more useful or realistic ones.

This can be a challenge for people with mental health disorders, as their thinking styles can be well-established.

How do we break negative thinking styles?

Some psychological theories suggest that we learn these negative thinking patterns through a process called negative reinforcement.

For example, if you have a fear of spiders, by avoiding them you learn that your anxiety levels can be reduced. So you're rewarded in the short term with less anxiety but this reinforces the fear.

To unlearn these patterns, people with phobias and anxiety disorders often use a CBT technique called graded exposure. By gradually confronting what frightens them and observing that nothing bad actually happens, it's possible to slowly retrain their brains to not fear it.

How does cognitive behavioural therapy work on the brain?

Primitive survival instincts like fear are processed in a part of the brain called the limbic system. This includes the amygdala, a region that processes emotion, and the hippocampus, a region involved in reliving traumatic memories.

What's more, studies have found that CBT can also change the prefrontal cortex, the part of the brain responsible for higher-level thinking.

So it seems that CBT might be able to make real, physical changes to both our "emotional brain" (instincts) and our "logical brain" (thoughts).

Intriguingly, similar patterns of brain changes have been seen with CBT and with drug treatments, suggesting that psychotherapies and medications might work on the brain in parallel ways.

How effective is cognitive behavioural therapy?

Of all the talking therapies, CBT has the most clinical evidence to show that it works.

Studies have shown that it is at least as effective as medication for many types of depression and anxiety disorders.

But unlike many drugs, there are few side effects with CBT. After a relatively short course, people have often described long-lasting benefits.

"In the trials we've run with post-traumatic stress disorder [PTSD] and social anxiety disorder, we've seen that even when people stop the therapy, they continue improving because they have new tools in place and they've made behavioural and thinking style changes," Dr Wild explains.

Since the focus is on tackling the here and now, people with more complicated roots to their mental problems which could stem from their childhood, for example, may need another type of longer-term therapy to explore this.

CBT also relies on commitment from the individual, including "homework" between therapy sessions. It can also involve confronting fears and anxieties, and this isn't always easy to do.

Ultimately, as with many types of treatment, some people will benefit from CBT more than others and psychologists and neuroscientists are beginning to unravel the reasons behind this.

ایک تحقیق کے مطابق وہ لوگ اپنی صحت خراب کر رہے ہیں جو دفتر کے بعد بھی اپنے سمارٹ فونز، ٹیبلیٹس اور لیپ ٹاپس پر کام کرتے رہتے ہیں۔

چارٹرڈ سوسائٹی آف فیزیوتھراپی کے مطابق لوگ ان آلات کے ’غلام‘ بن کر رہ گئے ہیں اور اکثر یہ لوگ سفر کرتے وقت یا گھر پر بھی سمارٹ فونز، ٹیبلیٹس اور لیپ ٹاپس کا استعمال کر رہے ہوتے ہیں۔

سوسائٹی کے بقول یہ آلات استعمال کرتے وقت وہ کس طرح بیٹھے یا لیٹے ہوتے ہیں اس کی وجہ سے ان کو کمر یا گردن کا درد ہو سکتا ہے۔

یونینز کا کہنا ہے کہ لوگوں کو اب جان لینا چاہیے کہ کس وقت اپنے آلات بند کردیے جانے چاہیے۔

ایک آن لائن سروے کے مطابق 2010 نوکری کرنے والے افراد میں سے دو تہائی افراد کا کہنا تھا کہ وہ دفتری اوقات کے بعد بھی سمارٹ فونز، ٹیبلیٹس اور لیپ ٹاپس استعمال کرتے ہیں۔

سوسائٹی کے مطابق دفتری اوقات کے بعد بھی لوگ اوسطاً دو گھنٹے سکرینز کے سامنے گزارتے ہیں۔

اعداد و شمار کے مطابق لوگ زیادہ وقت سمارٹ فونز، ٹیبلیٹس اور لیپ ٹاپس پر اس لیے بھی گزار رہے ہیں کہ ایک تو ان پر کام کا بوجھ بہت ہے اور وہ دفتر میں کام کا بوجھ کم کرنے کے لیے دفتری اوقات کے بعد کام کرتے ہیں۔

سوسائٹی کی سربراہ ڈاکٹر ہیلینا جانسن کا کہنا ہے کہ یہ تشویشناک بات ہے۔

’اگر تو لوگ کبھی کبھار دفتری کام گھر لے جائیں تو ٹھیک ہے لیکن اگر یہ عادت بن جائے تو کمر اور گردن کا درد ہو سکتا ہے۔ حہ خاص طور پر اس وقت صحت کے لیے مضر ہے جب لوگ ہاتھ میں لیے جانے والے آلات استعمال کر رہے ہوتے ہیں اور جس طرح بیٹھے ہیں اس کا خیال نہیں کرتے۔

برطانیہ میں گھریلو تشدد کی تعریف کو وسیع کر کے اس میں نفسیاتی طور پر ڈرانے دھمکانے کو بھی شامل کیاگیا ہے۔ اس نئی تعریف کا اطلاق اٹھارہ سال سے کم عمر کے بچوں پر بھی لاگو ہوگا۔

اس نئی تعریف کے مطابق اپنے شریک کے گھر سے باہر نکلنے پر پابندی لگانے یا فون پر رابطہ نہ کرنے دینے پر بھی قانونی کارروائی کی جا سکتی ہے۔

امید ہے کہ گھریلو تشدد کی تعریف کے دائرہ کو وسیع کرنے سے لوگوں میں اس کے بارے میں بیداری پیدا ہوگی اور یہ بھی معلوم ہوگا کہ کون گھریلو تشدد کا شکار ہے۔

برطانوی دفترِ خارجہ کا کہنا ہے کہ اس کے بعد گھریلو تشدد کے زیادہ واقعات سامنے آئیں گے۔

دفترِ خارجہ کا یہ بھی خیال ہے کہ زیادہ تر نوجوان آگے آئیں اور اپنے ساتھ ہونے والے گھریلو تشدد کے بارے میں مدد مانگیں یا پھر کسی کو اس بارے میں بتائیں۔

یہ تبدیلیاں 2013 مارچ سے نافذ ہوں گی جو مقامی حکام، پولیس اور رضاکار تنظیموں کی اپیل پر کی گئی ہیں۔

گھریلو تشدد کی شکار ایک خاتون نے اپنا نام ظاہر نہ کرنے کی شرط پر بتایا کہ اگر یہ رہنماء اصول پہلے موجود ہوتے تو شاید انہیں اتنی تکالیف نہ اٹھانی پڑتیں۔

انہوں نے بتایا کہ ان کے ساتھ تشدد کیاگیا تاہم اس سے کہیں زیادہ انہیں نفسیاتی اور جذباتی طور پر پریشان کیا گیا۔

اس خاتون کا کہنا تھا کہ انہیں اس حد تک کنٹرول کیا گیا کہ ان کا اعتماد پوری طرح ختم ہوگیا جس کے بعد وہ خود پر بھی بھروسہ نہیں کر پا رہی تھیں۔

ان کا کہنا تھا چونکہ ان کے ساتھ مار پیٹ سے زیادہ انہیں نفسیاتی اور جذباتی طور پر حراساں کیا جاتا رہا اسی لیے وہ خود کو گھریلو تشدد کا شکار تصور نہیں کرتی تھیں۔

خاتون کا کہنا تھا کہ اگر انہیں اس بارے میں علم ہوتا کہ وہ جذباتی اور نفسیاتی تشدد کا شکار ہیں تو وہ اپنے ارد گرد ہو رہے واقعات کا اندازہ لگا پاتیں اور بہت پہلے ہی مدد حاصل کر لیتیں۔

پولیس چیف کانسٹیبل کامل نیپئیر کا کہنا ہے کہ گھریلو تشدد کی تشریح میں اس تبدیلی سے لوگوں میں اس بارے میں بیداری پیدا ہوگی