Have you heard that the Universe is expanding? Edwin Hubble changed astronomy in the 1920s by discovering this, but did you also know that the expansion of the Universe is actually accelerating? This was one of the biggest surprises in Cosmology back in 1998, leading to the discovery of the mysterious Dark Energy that makes up the vast majority of the energy density of the Universe. Now to measure the expansion of the Universe, astronomers needed a way to accurately determine extreme distances.
One of the most effective ways to do this is to look at the apparent brightness of lights of a known magnitude. Because light energy fades in a very predictable way (inverse square falloff), you can determine the distance accurately as long as you know the absolute brightness. So try this thought experiment: if you went out on a deserted road at night and placed 100 watt light bulbs along the road every hundred meters, the closest lights would be the brightest and the farthest would be the dimmest - yet in reality they are all of the same absolute brightness. If you stand next to each of them, they put out 100 watts of energy, but the light traveling from the farther ones loses energy, so it appears dimmer. So by measuring the brightness of each light you could determine the distance because you know how bright it actually is and how bright it appears; essentially just by measuring the loss of energy over distance.
So how do we do this to measure the distance to stars? As you can see in the image to the right, stars come in a wide variety of sizes and brightness (click to enlarge). From the relatively cool, tiny Red Dwarf to the hottest, most massive blue Hypergiants, the brightness of stars varies considerably even amongst the same type. With so much variation, it would be impossible to accurately use brightness to measure distance. If only there was a class of bright object scattered throughout the Universe that always had the same brightness? It turns out there is!
If you have friends or family who take Astrology seriously then you’ve probably heard the phrase “Mercury in retrograde”. It’s typically used to designate a time when not to do certain things or be weary because of what the planet Mercury is doing, which by the term “retrograde” they mean Mercury is moving backwards.
First off, it never made sense to me that hunks of rock or gas giants orbiting the Sun would have some say in our lives, but the more important question that should be asked is “does Mercury actually move backwards at any time in its orbit?” The answer is a resounding “no!”.
It’s a well established scientific fact that all of the planets in our solar system orbit the Sun in slightly elliptical orbits much like satellites orbit the Earth. They are massive and they are in motion and cannot change that motion without a sufficient mass disturbing their trajectory. Yet, Astrologers will claim that some planets will go backward in their orbits. Why is this?
In ancient times, people looking up at the night sky noticed that the stars all moved together in the same direction. Later we realized this was because the Earth was rotating and our viewing angle was actually changing over time. However, they noticed that a few of these stars moved in less predictable patterns over the course of the years. These wandering stars were dubbed “planets” by the Greeks and the name stuck centuries later. But it took a heliocentric view of the Solar System for early astronomers to understand exactly why these planets were moving the way they do.
The trick was understanding that the Earth and the planets are orbiting the Sun and that the farther the planet is away from us, the longer it takes to move around the Sun. For this reason as the observer moves around the Sun, the other planets will appear to change directions relative to the observer over time.
So to someone watching Mercury, which orbits much faster than the Earth, at a predictable time of year, the path of Mercury will appear to change, moving backwards a bit before moving again with the Earth – hence a retrograde motion.
So to recap, in ancient times people thought the planets actually changed direction, however scientific observation showed that this was in fact false and that they only appeared to change direction because of the observer and observed object being on mutually orbiting trajectories – old thinking proven wrong over time. Yet to this day astrologers still refer to these planets being in retrograde. This is of course why Astrology is to Astronomy what Alchemy is to Chemistry.
So the next time someone tells you Mars or Mercury are in retrograde, remind them that they’re working with bad information.
One of my hobbies that’s a carry-over from my years as a soldier in the Army is long range shooting. Understanding and exploiting the science of ballistics lets me take a particular load of ammunition and compute a predicted trajectory based on environmental factors such as barometric pressure, altitude and wind. But there’s also an art form to creating a stable shooting platform with your body, controlling your breathing and making the shooting process fluid, not to mention estimating the wind speed and direction downrange.
Here’s a clip from a recent shoot out in the desert. The targets are 10×17″ AR500 steel targets – about the size of a laptop screen.
Update: I just came back from another trip out to the same area and this time made a few hits on the steel targets at a whopping 1750 yards. Time of flight to the target was almost 2 seconds and it was another 3 seconds before we heard the report.
What the hell is that? It looks like a comet, doesn’t it? But it’s not. Spectral analysis of the tail shows that it’s not gas and orbital analysis says it’s connected to the Flora family of near Earth asteroids. What you’re looking at here is most likely a very recent asteroid impact with the debris trailing off, driven by the solar wind. Initially the Lincoln Near-Earth Asteroid Research (LINEAR) sky survey discovered the unusual site and then Hubble was pointed at it to reveal the detail you see above.
This is pretty amazing and the very first time we have witnessed an asteroid collision!
When I was in 1/10th SFG(A) back in the 90s, we had a month dedicated every year to teaching, developing and practicing winter warfare skills and techniques. This was important because all three battalions of our Special Forces Group was regionally aligned to operate in all of Europe and that meant we had to be prepared to operate in mountainous regions such as the Alps or the Fjords of Scandinavia. For that reason we had to learn not only how to survive in snowy conditions but also how to fight and win. Much of this training was just down right fun, be it learning how to cross country ski or travel via snow mobiles, but there was also a very important tactical component to it that required training and practice to develop.
Since the GWOT began, all of the SF Groups have been very busy operating in Afghanistan and Iraq – a region that only 5th Group is regionally aligned and trained for. This has required every team that rotates through the region to learn new skills, culture and languages that they normally aren’t trained for, and this has been going on for over eight years now. Unfortunately, many of those regional specialty skills are quite perishable, especially language skills. So it made me happy to see members of my old SF Group out in the snowy Rocky Mountains training hard in winter warfare between rotations. Even though these winter skills apply to certain parts of Afghanistan and northern Iraq, it’s very easy to see how over the years they could be ignored in favor of focusing Central Asia-oriented skills.
So “Avatar” has been out for a few weeks now and I’m sure many of you have seen it. If you haven’t, I highly suggest checking it out – especially in 3D. Director James Cameron envisioned a lush world populated with rich texture and detail and used an army of visual effects artist to create it. The story isn’t something new, but the experience of “Avatar” is.
There is however one key plot point that I’d like to talk about and a related evolutionary story, so if you haven’t seen the movie yet, you may want to wait to read this.
Well, now that the underwear bomber has been tied to Islamic terrorists in Yemen, all eyes in the West seem to be once again paying attention to the situation in Yemen. This hasn’t really happened since since the Cole bombing in 2000 in the port city of Aden or in 2002 when the first known offensive Predator interdiction took place. But there’s a problem here that I’m afraid many are missing.
Yemen in many ways is like Afghanistan or nearby Somalia, with a very weak central government and a handful of powerful insurgent groups to challenge it. Not all of these groups are religious extremists- many are just tribal groups vying for power in a fractured country. Regardless, they all threaten a monetarily poor and politically weak government that doesn’t have a whole lot of friends around the world. The government’s inability to control the outlying countryside has even led to Saudi forces launching air strikes inside of Yemen against cross border insurgent groups.
So I suspect the Yemeni government is seeing the latest attention pointed their way as a chance to bring in some much needed funding as well as allies. All they really have to do is convince Western powers that these groups that threaten them are all linked to al-Qaeda, are a threat to the West and can be neutralized with large sums of money, equipment and training. So if you can’t see where I’m going with this, the danger is that we end up getting suckered into a situation where someone is playing “the enemy of my enemy is my friend.” Granted, I don’t think we have much of a choice seeing how threats like al-Qaeda will always seek safe haven in lawless areas, but we would be wise not to get sucked into a situation that could backfire on us.
Critical Thinking in many ways forms the backbone of Science because it uses logic and reason to come to conclusions devoid of emotional influences. Personally I have a hard time seeing how people can see this as a problem because quite simply “it works”, yet I’m often dismayed by a substantial portion of the public specifically because they do not embrace Critical Thinking. Perhaps this is because it (and Science for that matter) gets only cursory exposure in our basic education system, but I suspect the main culprit is parents and the way they raise their children. Political and Religious ideologues completely ignore Critical Thinking, instead valuing what I like to call “Emotional Thinking.” No doubt there’s a time and a place for emotions, but when it comes to understanding reality or seeking truth, emotions can be horribly unreliable.
The author of a previous video on Open Mindedness has posted a new video about Critical Thinking that’s an excellent primer on the concept and shows why it’s not only effective but something we should all strive to do.
I’ve often said that technology is the great anachronism. What I mean by that is that technology identifies a period in time better than anything else. Anything that has a “style” attached to it, be it clothing, architecture or even language, would seem an obvious choice for an anachronism, but those things have a tendency to change and return in various forms, being cyclical in nature. Technology on the other hand rarely, if ever, takes a step back. When we look at a picture of an artist in his home with an early Macintosh, we can pretty much assume it’s from the mid-80s just the same way we can look at a picture of a person talking on brick of a car phone with the curled cord going into the console and say “early 90s.”
Personally, I think it’s when a technology that has become such a staple of modern life becomes obsolete, that’s when we really notice what I’m talking about. For example, from 2000 to 2010, several stalwart technologies we’d all grown up around more or less disappeared. Who uses phone books now? When was the last time you bought a CD in a store? Or had a land line installed in your home? Or best of all, used a phone booth on the streets, let alone see one in operation?
This is a bit old but quite good footage worth talking about…
The Yarmouk Traffic Circle was a particularly bad location in Mosul when I was there in 2004-2005, often the site of some bad ambushes by the bad guys as well as IEDs. In this video, special operations aviation is doing gun and rocket runs on targets in the area. You’ll notice that they have a pattern to their runs: miniguns, cannon, then rockets.
The DAP is the brainchild of famed Nightstalker Cliff Walcott, who died in Operation Gothic Serpent in Somalia. Up until that point, the only attack helicopters used by the 160 Special Operations Aviation Regiment were AH-6 Littlebirds, armed with 7.62mm miniguns and 2.75″ rockets. While agile and capable, the AH-6s don’t have the range nor the payload for sustained fire support missions, so operations that required heavier support relied on coordinating with conventional AH-64 Apache elements. The compartmentalized nature of special operations often made this difficult, so it was determined that an “intermediate level” attack capability for the 160th was required. The DAP was born out of this requirement by taking an MH-60, special operations variant of the UH-60 Black Hawk helicopter, and fitting it for attack purposes.
MH-60s normally mount 7.62mm miniguns on door mounts to provide defensive fire when ferrying troops to and from targets. Because the DAPs mission is purely offensive, the miniguns are locked forward firing and hard points are mounted to the fuselage allowing a wide variety of munitions. The most common configuration is large 2.75″ rocket pods (larger than the ones carried by the AH-6) and a 30mm chain gun (the same used on the Apache gunship). This is what is seen in the video with the forward mounted miniguns roaring onto the target followed by the 30mm chaingun and rockets. DAPs can also mount Hellfire laser guided missiles for longer range precision standoff capability as well as Stinger missiles for anti-aircraft needs.
There’s a similar video out there of DAPs doing runs near the MAF (Mosul Airfield) at “Gilligan’s Island.” There aren’t any active targets in that video – it’s more a series of practice runs or a “show of force” on the south side of the runway in a wide open area bad guys liked to setup mortars in.
Have you heard that the Universe is expanding? Edwin Hubble changed astronomy in the 1920s by discovering this, but did you also know that the expansion of the Universe is actually accelerating? This was one of the biggest surprises in Cosmology back in 1998, leading to the discovery of the mysterious Dark Energy that makes up the vast majority of the energy density of the Universe. Now to measure the expansion of the Universe, astronomers needed a way to accurately determine extreme distances.
