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I bet you didn't know that this thread would have a part 2
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If you go to Dublin City Council offices by the quays, there's an amphitheatre. Stand in the middle of the circle, on the centre stone and talk towards the angle of the two buildings, and your voice echos like crazy. Take a step to the left or right, and it doesn't work. And no one else can hear the echo outside the centre stone either...0 -
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Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 6,306 Mod ✭✭✭✭
Join Date:Posts: 6207
Burmese pythons have overrun the Florida Everglades.
A lot of this can be attributed to Hurricane Andrew destroying a breeding facility in 1992, which released hundreds of snakes into the wild. The Everglades was also where a lot of exotic pet owners dumped their Burmese pythons (and other pets) which was also a contributing factor.
An evaluation of the genetic structure of Burmese pythons sampled from Everglades National Park determined that the population is genetically distinct from pythons sampled in the native range, but within the Everglades population, there is little genetic diversity. This finding suggests that the python population is freely interbreeding or corroborates the hypothesis that the individuals originate from a specific source population such as the pet trade
Unsurprisingly, they are considered an invasive species in the area and are much larger than the native snakes. They don't shy away from the alligators either. As a general rule, they are not fussy eaters and will eat pretty much anything. Unfortunately, this means that populations of raccoon, opossum, bobcat, rabbit, fox, and other mammals have declined.
How to fix the problem is tricky. As Burmese pythons spend a majority of their day in hiding in burrows or aquatic habitats, making it a tough job to track them down. Quite a large number would be in areas that would be inaccessible to humans, so this makes culling a difficult task. Estimates of python populations range from at least 30,000 to more than 300,000.
What follows is speculation. There are fears that they may colonise other parts of the US. However, in times past, research showed that pythons could not survive the winter temperatures in an experimental enclosure in South Carolina. It was concluded that on the off chance that they did decide to venture north, the weather would stop any expansion. This was until the winter of 2010 which saw Florida get hit by a cold snap. Investigators reported dead snakes coiled along canal banks and in outdoor enclosures. However, numerous snakes survived this cold spell, potentially by using behavioural mechanisms (such as seeking refuge underground). If these behavioural traits are heritable, it could be possible that the winter of 2009-2010 served as a selection event for more cold-tolerant pythons. Therefore it is possible that this selected population of pythons would have an enhanced ability to spread northwards and extend the python's invasive range.
Alligator and Burmese pythron at the Everglades.0 -
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Today, the day is as long as the night - it's the spring equinox. It actually occurs at 21:58 in Dublin:
"An equinox is the exact instant when the Sun is directly overhead the Equator and the Earth's rotational axis is tilted neither towards nor away from the Sun. In technical terms, this means that at the instant of the equinox, the Earth's celestial equator, which is the equator's imaginary projection into space, intersects with the center of the Sun."
Currently, days are getting longer at the rate of about 4.5 minutes per day (so about half an hour a week), which is about the highest rate that it changes.
Despite the 21st being commonly considered the equinox day, it actually fluctuates between the 19th and 21st of March dependent on many factors including the actual length of a year.
https://www.timeanddate.com/calendar/varying-march-equinox-date.html
https://www.timeanddate.com/calendar/spring-equinox.html0 -
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And 21th of March is one of the most important days to determine what day Easter will be. First Sunday after the first Full Moon occurring on or after 21th of March.
So the earliest Easter Sunday is possible on 22th of March, the latest on 25th of April.
https://www.timeanddate.com/calendar/determining-easter-date.html
In an entirely separate matter, March 21st is the birthday of multiple stars such as F1 legend Aryton Senna, fricking James Bond Timothy Dalton, Oscar winner Gary Oldman, one of the greatest ever football managers Brian Clough, current world snooker champion Mark Williams, world cup winners Lothar Matthaus, Ronaldinho and Antoine Greizmann, and other Champions League winners Jordi Alba and Ronald Koeman......
......and yours truly.
A great list of people
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Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 6,306 Mod ✭✭✭✭ Join Date:Posts: 6207
The Sargasso Sea is a region of the North Atlantic Ocean bounded by four currents forming an ocean gyre. Unlike all other regions called seas, it has no land boundaries. It is distinguished from other parts of the Atlantic Ocean by its characteristic brown Sargassum seaweed.
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The Sargasso Sea is a region of the North Atlantic Ocean bounded by four currents forming an ocean gyre. Unlike all other regions called seas, it has no land boundaries. It is distinguished from other parts of the Atlantic Ocean by its characteristic brown Sargassum seaweed.
It’s also considered the spawning ground for European eels.
https://en.m.wikipedia.org/wiki/Eel_life_history0 -
You get in your car and drive a set distance and come to a stop.
You got displaced, your position changed. We can calculate your velocity by dividing the distance you traveled by how long it took you to go that distance. So Velocity is the first derivative of position (displacement). The second derivative of position, again with respect to time, is Acceleration. This will be the rate of change in your velocity.
The third derivative of position will be Jerk, the rate of change in your acceleration (i.e. the rate of change of the rate of change of the rate of change in your position). This is rarely used and less so are the subsequent derivatives where a little fun was had with naming them
The fourth derivative of an object’s displacement (the rate of change of jerk) is known as Snap (also known as jounce), the fifth derivative (the rate of change of snap) is Crackle, and the sixth derivative of displacement is Pop.
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It's interesting to note why they are rarely used. The forces of nature only affect acceleration. So an electromagnetic field, friction, power from an engine in a moving vehicle etc only cause you to accelerate or decelerate.The third derivative of position will be Jerk, the rate of change in your acceleration (i.e. the rate of change of the rate of change of the rate of change in your position). This is rarely used and less so are the subsequent derivatives where a little fun was had with naming them
Jerk and the other higher derivatives only get altered as a consequence of how acceleration gets altered, they don't change independently on their own, so they're of little interest.
The lower derivatives, position and velocity are also almost completely set by acceleration. You just have to know something's initial position and velocity and then the way forces affect acceleration tells you what the position and velocities will be for the rest of time (in Classical Physics).
The fact that the (Classical) laws of physics only care about acceleration is simpler to see from the point of view of being in a spaceship. Even if it is moving at a massive velocity, like being on a plane you don't feel a thing. However you do feel the accelerations and decelerations which have to be gentle enough not to crush the crew.
This was the fundamental insight of Newton's Second Law: F = ma, Forces (F) only relate to acceleration (a).
This is also part of what led Einstein to General Relativity. He realised that when somebody falls to Earth from space they don't feel anything. If they were being accelerated they should feel something from Newton's Second Law, but they don't. So despite appearances somebody falling under gravity isn't really accelerating and thus gravity mustn't be a force. Of course this leaves the confusion of how come they fall along curved trajectories if they're not accelerating, things not accelerating should move along straight lines.
He very quickly realised something's path can be curved from moving on a curved surface, not due to bending themselves. Like how lines on a sphere converge on the North pole:
So gravity must be from spacetime curving and not a force.0 -
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Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 6,306 Mod ✭✭✭✭ Join Date:Posts: 6207
The Amazon and Congo used to be the one river system.
Back when the continents were all together as Gondwana, the Amazon flowed west as part of a proto-Amazon-Congo river system, from the interior of what is now present day Africa.
Around 15 millions years ago the South American and Nazca plates collided and formed the Andes. The rise of the Andes and the linkage of the Brazilian and Guyana bedrock shields, blocked the river and caused the Amazon to become a vast inland sea. Over time this inland sea became a large swampy, freshwater lake and the marine inhabitants adapted to life in freshwater. For example, over 20 species of stingray, most closely related to those found in the Pacific Ocean, can be found today in the freshwaters of the Amazon.
Ten to eleven million years ago, waters worked through the sandstone from the west and the Amazon began to flow eastward, and this led to the emergence of the Amazon rainforest. During Ice Ages, sea levels dropped and the great Amazon lake rapidly drained and became a river, which is the Amazon we know today.
Below is South America and Africa merged when they were part of Gondwana.
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Do you know why Cork was first called the Rebel County?
Hint: it wasn't anything to do with Michael Collins or the War of Independence.If you think that Cork is known as the Rebel County because of Michael Collins and the Flying Columns of the Old IRA, think again.
In what is surely a very Corkonian twist, the city was judged to be rebellious because of its loyalty to (one version of) the British Crown and the dispossessed House of York in the English War of the Roses.
When a young and handsome Flemish man called Perkin Warbeck arrived in Cork in 1491, he was proclaimed to be one of the princes in the Tower, the two sons of King Edward IV who had mysteriously disappeared after they were locked up in the Tower of London by Richard III. The merchants and burghers of Cork supported Warbeck (or Richard, Duke of York as he claimed to be) in what became a futile effort to reclaim the throne for the Yorkists.
And Cork was thus declared a Rebel county by King Henry VII (who later pardoned Warbeck's Irish supporters, remarking: "I suppose they will crown an ape, next.")
Lovely place, great people, but Perkin Warbeck! Up da rebels. 0 -
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Moderators, Science, Health & Environment Moderators, Society & Culture Moderators Posts: 6,306 Mod ✭✭✭✭ Join Date:Posts: 6207
Okay I just wanted to say I've read over 40 popular books on quantum physics over the past few months in order to make a recommendation on this thread. I went through them critically for accuracy and minimal sensational bollocks. The best are:
Nicolas Gisin: Quantum Chance: Nonlocality, Teleportation and Other Quantum Marvels
Terry Rudolph: Q is for Quantum
Philip Ball: Beyond Weird
Gisin requires some ability with basic algebra, Rudolph requires nothing more than adding and subtracting, Ball is just words.
My experience is that different books work for different people. You might not make heads or tails of Rudolph, but Gisin will simply click. Gisin approaches the subject as a scientist (he's one of the best physicists alive), Rudolph as a computer scientist/programmer and Ball like a philosopher and journalist.
On average I think most people will prefer Rudolph and that would be my top recommendation. This is because:- It is short
- You come out knowing a decent bit about how QM works in practice
- He is up front about what is odd about it. I noticed many popular science books shy away from directly saying QM casts doubt on Energy or momentum being real properties of the subatomic world for example, but Rudolph directly says it.
- He sticks to the majority opinion of most physicists (unlike Ball, see below).
- It's also the cheapest.
However I would keep the other two in mind, Gisin if you don't mind maths and Ball if you do. The reasons I don't have them at the top is that Gisin is a bit math heavy in places for some and Ball I think revels in how confusing QM is at times and some people I lent it to became a bit confused toward the end as multiple paradoxes and alternate minority opinions were piled on. Gisin has a bit about what QM might mean for humanity and free will if you are interested in those topics.
Thank you, Fourier.
I have noticed, and always appreciated, that in this thread you always go that extra-mile to ensure that those of us with no physics background don't get left behind when it comes to stuff like QM and other hard to grasp concepts.
Likewise with reading the books to make a thread recommendation, that's a very kind gesture and thank you for going to the effort.
Like I said, it doesn't go unnoticed and it is greatly appreciated.
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If anybody buys these and has questions from reading them don't hesitate to contact me.Thank you, Fourier.
I have noticed, and always appreciated, that in this thread you always go that extra-mile to ensure that those of us with no physics background don't get left behind when it comes to stuff like QM and other hard to grasp concepts.
Likewise with reading the books to make a thread recommendation, that's a very kind gesture and thank you for going to the effort.
Like I said, it doesn't go unnoticed and it is greatly appreciated.0
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