Black Holes and White Galaxies

The largest black hole that we know of, at least in nearby galaxies, is the black hole in galaxy M87.

M87 is not our galaxy. Earth and the other planets we know and love are part of the Milky Way Galaxy, so named because of the dense band of stars that passes through it creating a milky-white colored path. This milky white band of stars is only apparent as such from a certain vantage point. From here on Earth, all of the stars we see in the night sky are actually a part of the Milky Way. As such, our galaxy is a relatively light place.

Black holes are areas of the universe so dense that not even light can penetrate them. Thus, these areas appear as black regions, and appear to literally suck the light from surrounding regions inward. The idea that black holes such everything inward is a bit of science fiction. However, they are literally so dense that they can in essence have their own level of extreme gravity. Once objects get close enough to the black hole they can only go onward into the hole because of this gravitational effect. The point of no return, beyond which light or other objects will go forward into the hole, is called the Event Horizon, so named because any event (light emission or other) that happens beyond this point will not be observable outside the hole. Therefore it is impossible to determine if the event occurred at all.

The black hole in the Milky Way Galaxy is a mere 2 billion solar masses, or 2 billion times the mass of our sun. Some estimates place this at closer to 4 billion. But, even that number pales compared with the black hole in M87. The black hole in M87 is now estimated to be 6.6 billion solar masses.

These super massive black holes are probably formed by merging smaller black holes. Smaller black holes are commonly formed by collapsing stars. Once a star runs out of fuel to burn, it cannot maintain itself and collapses in on itself, succumbing to its own gravity. If the star was dense enough, it will form a stellar black hole as a result of this event.

M87 appears to be the result of hundreds or more mergers of smaller black holes, and could now swallow our whole galaxy. In fact, it could swallow more than 4 of them. But, we are in no danger. The M87 black hole is also more than 50 million light years away from Earth.

In addition to being the largest black hole on record, M87 provides physicists their best chance to study black hole physics, which, by and large, is still only theory at this point.

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Can we still make a difference?

Global warming, climate change, rising sea-level…oh my. Some believe it is real, some believe it is a myth. Regardless of what you believe, it seems we hear about it constantly these days. You cannot escape it.

I personally think that some level of global climate change is real. We just cannot possibly be emitting that much pollution and smoke and carbon products into the atmosphere and not have some impact. How big is the impact? I don’t really know. But I am willing to try to do my bit to make the impact a little less. Whether you believe the earth is a gift from a Creator, or that it was created by the Big Bang, either way it is now ours to care for and we should indeed do our best to do so.

The problem is that this global climate change stuff is so hyped up by the media that we have become numb. The ‘doom and gloom perspective’ is that things are so bad, you just cannot think about the repercussions of all this global change without basically wondering why we should even bother. It is the only alternative. If you believe the doom and gloom, and lets face it, the media is driven by such extremes, then it almost paralyzes you with fear. If you think about it too hard, it could send you into a full on panic. What will our kids’ lives be like? Our kids’ kids?

And, so, we are largely numb to the problem. So numb that it has become almost hip to not care. It is like a defensive mechanism we collectively have evoked.

So, it is wonderfully reassuring to read a story where we find we can still make a difference. Recent research into the fate of the polar bears and the retreating sea ice gives us that hope. Polar bears, as a species, were given a fatal diagnosis a couple of years ago. With the loss of sea ice, they were losing their habitat, and were predicted to be extinct by 2050.

The most recent models still support that result, as reported by the National Center for Atmospheric Research in Boulder, Colorado. However, they also have begun to experiment with the effects of reductions in green house gasses. The good news is that rather moderate reductions, like those being planned by some countries, would actually slow the ice loss to a point that major areas of polar bear habitat would be protected.

Are we going to be able to do that – to reduce emissions? Only time will tell. But it is sure reassuring to know that we can still stop the effects of what is so often pitched as ‘the end of the world’

Wikipedia – Why you should care…

Today’s column is not so much a scientific rant, like I normally provide, but a plea:

Support Wikipedia.

What is Wikipedia? It is an on-line encyclopedia of sorts. It is the 5th most visited site on all of the internet. More than 400 million people use Wikipedia and its sister sites every month, so they claim. It has information on just about everything. I use it often when I teach, admittedly checking the facts against my own understanding of a subject before referring students to the site, but it is nearly always correct. It has a level of accuracy, I think, that shames the entire rest of the internet, all sites combined.

Why is Wikipedia amazing? It provides information, for free, to anyone and everyone that wants access. And, after all, that is my motto, Science Is For Everyone. Although wikipedia is not just science, it is a collection of facts that has the same appeal as science, at least for me.

John Goma, an editor for Wikipedia, recalls “I found a Wikipedia article on a topic that I had studied when I was a math student. I noticed that a few important points were missing. I hit the edit button, made some changes, and I've been writing and editing ever since. “ He states “Wikipedia is the sum of all those moments of discovery by millions of editors like me. People across the world add their time and energy to the vast, ever-growing store of knowledge that Wikipedia has become. But what's really remarkable about Wikipedia is that it's the product of volunteers working one entry at a time. And because Wikipedia is free of advertising, those of us who create and use Wikipedia have to protect and sustain it.”

Imagine a world in which every single human being can freely share in the sum of all knowledge. That's Wikimedia’s commitment. The Wikimedia Foundation is the foundation raising the funds to keep Wikipedia alive.

Want to know where your money would go? A donation to Wikipedia/Wikimedia supports technology and people. The Wikimedia Foundation develops and improves the technology behind Wikipedia and nine other projects, and sustains the infrastructure that keeps them up and running. The Foundation has a staff of about fifty, which provides technical, administrative, legal and outreach support for the global community of volunteers who write and edit Wikipedia.
Many people love Wikipedia, use it every day, but a surprising number don't know it's run by a non-profit.

Just type Wikipedia in your browser search bar and you’ll be there. Support the quest for knowledge and free access to it.

For the love of Chocolate

Continuing with the Halloween theme, today I write about candy. And, not just any candy - chocolate. Almost everyone likes chocolate, and some of us love it. I know I am certainly guilty of raiding my kids’ trick or treat bags in search of the good stuff; which in my book is the solid chocolate without anything else getting in the way. No peanuts, no nuts, no crispies, no crunchies, no wafers, and not even caramel. Just chocolate.

What is it about chocolate that makes so many of us crave it. Turns out there is some solid science behind this apparent madness.

First of all, there is the chemistry. Scientists have discovered several properties of chocolate that literally lead us to crave it. One, it has opioids. Opioids are also found in opium. So, not surprisingly, chocolate, like opium, serves to dull pain and give a general feeling of calm and happiness. Of course, it is present in pretty small doses, so chocolate is a lot safer way to get these feelings! Two, chocolate has caffeine, which is an upper, which tends to make your heart beat just a little faster.

Second – the psychology. Because we tend to give gifts of chocolate to people we love, some theorize that eating chocolate can induce feelings of comfort and/or love for purely psychological reasons. Given the chemistry above, and the biological responses, it is no wonder people have associated chocolate with love. But our resulting cultural association of chocolate with love has trained our emotional responses as well. Even without the underlying chemistry, giving, receiving, or just eating chocolate tends to induce happiness.

Third – the biology. Chocolate really is good for you, at least in moderation. Chocolate contains antioxidants, and flavenoids, both of which are thought to increase your life span through their cardiovascular benefits. In simpler terms, chocolate is good for your heart, biologically-speaking. And, we know that our bodies tend to crave the things that are good for us. It is our bodies’ way of telling us we are short on particular nutrients.

Of course, we also routinely crave what is not so good for us, and too much chocolate definitely falls into that category as well. Chocolate has lots of fats, and sugars. The fact that it contains all those fats, which make it smooth, may also explain some of why we like it so much - the sensation of eating it.

So whatever the reason, enjoy!

Spooky Spiders…

October seems the appropriate month to continue on the theme of spiders and other creepy crawlies who happily decorate our homes right now in larger-than-life form. Last time I wrote about spider silk, and its amazing strength. Spiders are biological wonders from several other perspectives as well. Notably, their long and leggy legs.

First, have you ever noticed that when you find a dead spider, that its legs are all curled up (so long as it is not smashed, that is)? Their legs roll inward towards their bodies and form a sort of ball. This is because spider legs are hydraulic, like pistons. They are held rigid by the fluid inside them, and that fluid must be maintained at pressure in order for them to hold the spider up and allow it to move around. Once the spider dies, the pressure cannot be maintained, and the legs collapse.

To move, the spider has muscles within the legs that allow the seven (yes seven) sections of each leg to bend inward a coordinated manner. But, to straighten the leg, there are no opposing muscles in most spiders, because there is nothing to attach them too. Remember spiders have no bone, just their tough exoskeleton that makes up what we think of as their crunchy skin or shell. The fluid pressure in the leg is changed via changes in the spider’s blood pressure. Increases in pressure straighten the leg, decreases allow it to bend.

Jumping spiders are by far the best at this feat. They can quickly change the blood pressure in the legs which allows them to spring upwards, travelling as far as 25 times their body length. That’d be 25 to 30 feet for the average human. None of us can pull that off.

Running spiders are special again in their own way. They have given up web building entirely for the purposes of capturing food, and obtain their meals hunting them down and then overtaking them with sheer speed. Our common wolf spiders often hunt this way. Luckily, even the largest of wolf spiders is only about an inch long, because spiders running you down is enough to unnerve just about anyone. They play an important role in the control of other insects, however, so be thankful that they are there.

Fishing spiders, however, win the award for amazing legs. Fishing spiders can literally walk on water. They do this by abusing the laws of physics, and taking advantage of simple surface tension. Surface tension is the tendency of particles of water to stick together. This is why you see a drop of water form a round, bead-like drop, and not just scatter into its infinitesimally small molecules. Fishing spiders have tiny leg tips, and light bodies, and when they press these leg tips to the surface of the water, they are able to stay atop the surface, and not break the surface tension. This is due largely to a waxy coating on the legs. You see a small dimple form on the water from the pressure of the leg, but the tension does not break, unless the spider wants it to. These spiders can dash out onto the water to grab prey such as insects, or reach below the surface to grab even small fish. And, when they really need to move, they can rise up on two legs and gallop across the water, reaching speeds of about 30 feet per second, or 2 miles per hour. The average running speed for a person is 6 miles per hour. The world record 100 m dash clocked in at 28 miles per hour. But, when they are just hanging around, or casually need to move from place to place, fishing spiders can also place their legs on the water and sail with the wind.

Not a bad way to get around.

Stronger than steel...

The strength of nature can be an impressive thing. Biologists, physicists, engineers and chemists alike often spend a lot of time just trying to figure out what makes things as strong as they are. What makes the shell of a clam rigid and tough? What makes the silk of a spider pliable yet strong?

This is an area of research called biomaterials. The study of biological substances and their physical properties in terms of measurements like strength and stiffness.

Recent research by scientists at the University of Puerto Rico has revealed that the toughest material on the planet is spider silk. In particular, the trophy goes to the web-spinning silk of the Darwin's bark spider, which lives on the island of Madagascar. This spider spins enormous webs that extend across rivers. Therefore, they must stretch and contract as the trees (to which they're anchored) move in the wind.

Spider silk, in general, is amazing stuff. It is a protein. It is both strong, meaning it resists breaking, and it is elastic, meaning it can deform and then recover its shape. Many materials have to trade off these properties. A substance can be very strong, like steel. But, steel is not elastic. If you bend steel, it will not return to its original shape. Spider silk, on average, has the same tensile strength as steel. But at the same time, it is very ductile, and can stretch about one and a half times its own length before breaking.

The bark spider of Madagascar spins fibers that are stronger than the strongest known man-made substance, which is Kevlar. Kevlar can resist about twice the force of steel. This is why they make bullet-proof vests from the stuff.

Spiders also can change the properties of their silk, by changing the water content of the silk. Most spiders can also weave more than one kind of silk, generally speaking there is strong silk that creates the support for the web, and sticky silk that catches the prey in the web. When you put these two abilities together, you end up with about a dozen distinctly recognizable kinds silk that can be produced by just one spider depending on the job at hand. The silk used to wrap up prey is even stronger than the silk used to support the web, and the silk used to form egg sacs is stronger still. Therefore, both of these silks are stronger, on average, than steel. At the other end of the spectrum, many spiders, particularly those that have just hatched, can extrude long, very thin strands of gossamer silk used for ballooning to new locations to settle and build their own webs.

The impressive properties of spider silk make it popular for study by engineers hoping to mimic Mother Nature. Unfortunately, it is not possible to create spider ranches so that the spiders can do the work for us. Spiders are not like docile cattle, making them extremely poor candidates for domestication. Spiders are aggressive and will eat one another, making it inadvisable to keep many spiders together in the same space. Reproducing the properties of the silk with man-made mimics is the only viable option, though scientists have created transgenic goats that will produce spider silk (I’ll save the ethical debate about that sort of process for a later article!).

For right now, the score is still Mother Nature 1, Humans 0 in terms of who can make the stronger substance.

Getting a Kick out of Physics

I’ve written before about the physics of baseball, and in particular how curve balls curve. But, this year’s World Cup Futbol (that’s Eurospeak for soccer you know) got me thinking about the physics of soccer and scoring goals. And, since it is that season for some of you parents, youth soccer season, that is, here you go…

The famous goal that recently got headlines again, in terms of the underlying science, was actually scored 13 years ago. In the June 3, 1997, match between France and Brazil. In the last seconds of the game, Brazilian Roberto Carlos scored what was later named the impossible goal. He kicked a ball towards one end of the goal, apparently way off target, that banked at the last second and dropped into the net. It tied the game and changed the team’s fate that year. It has the stuff of the mysterious dropping fastball in baseball.

The secret was finally revealed this year by a team of French (of course) scientists.

Soccer balls tend to curve or arc when kicked for much the same reason that curve balls curve in baseball. When they are kicked (or thrown) they tend to rotate. So, one side of the ball is rotating in the same direction as the ball itself, while the other side of the ball is rotating against the direction of motion. The side of the ball that is rotating against direction of motion gets slowed down, just a little, by the resulting friction, and the path of the ball starts to curve to that side. This is called the Magnus effect, which explains the gently curving motion we typically see in tennis balls, golf balls, etc. What about the radical change in direction, like with old-fashioned spit-balls and this famous soccer goal?

Spit-balls change drastically because the shape of the ball is altered. This causes the spin to be asymmetrical, and things start to wobble. Just think of your washing machine on the spin cycle with the load out of balance. It just takes one wobble to throw things really out of whack. If your washing machine drum were not attached to the machine, it would take one strong turn, and crash through your laundry room wall.

Something quite different apparently happened with this soccer ball. No alteration of the ball was required. It was simply that the ball was kicked from so far away that the Magnus effect went into overdrive, so to speak. The forces on the right and left side of the ball got so out of balance that it started to wobble on its own, and the result was just like a dropping curve-ball.

The key was that the kick was from really far away, 35 meters to be exact, and only a player like Roberto Carlos could deliver that kick with enough speed for it to actually make it to the goal, estimated at 130 kilometers per hour. Hence, you almost never see this happen. You never see it in baseball or tennis, the ball does simply not get to travel far enough. And, it is obviously incredibly rare even in soccer, kickers rarely deliver 100+ km/hr kicks.

In fact, scientists did not know this was the outcome of the Magnus effect until seeing that goal, and spending many years since then studying it. It has now been replicated in the lab. We have yet to see if improvements in player training technology will yield more Carlos-style performances.