Physics
esiegel | February 7, 2017"By preventing dangerous asteroid strikes, we can save millions of people, or even our entire species. And, as human beings, we can take responsibility for preserving this amazing evolutionary experiment of which we and all life on Earth are a part." -Rusty Schweickart
Asteroid strikes are among the most destructive natural disasters to ever impact planet Earth. While an extinction-level event, like the one that wiped out the dinosaurs some 65 million years ago, are exceedingly rare, we face city-killer impacts somewhere on Earth's surface every few hundred years.
Meteor (Barringer) crater,…
drorzel | February 2, 2017It's a new month now, so it's time to share links to what I wrote for Forbes last month:
-- Small College Astronomers Predict Big Stellar Explosion: I mostly leave astronomy stories to others, but I heard about this from a friend at Calvin College, and it's a story that hits a lot of my pet issues, so I wrote it up.
-- For Scientists, Recognition Is A Weird And Contingent Thing: Vera Rubin tops the list of great women in science who died in 2016, but AMO physics lost two great women but less famous women as well. I spent a while thinking about why they had such different levels of status…
esiegel | February 2, 2017"What we observe is not nature itself, but nature exposed to our method of questioning." -Werner Heisenberg
Empty space, according to quantum mechanics, isn’t exactly empty. Take away all the matter, radiation and anything else you can have populating your space, and you’ll still have some amount of energy in there: the zero-point energy of the Universe. One consequence of quantum electrodynamics is that this sea of virtual particles is always present, and a strong magnetic field can lead to some really bizarre behavior.
VLT image of the area around the very faint neutron star RX J1856.5-…
drorzel | February 1, 2017So, I tweeted about this yesterday, but I also spent the entire day feeling achy and feverish, so didn't have brains or time for a blog post with more details. I'm feeling healthier this morning, though time is still short, so I'll give a quick summary of the details:
-- As you can see in the photo (taken with my phone at Starbucks just before I took these to the post office to mail them), I signed a contract for a new book. Four copies, because lawyers.
-- The contract is with Oneworld Publications in the UK, who had a best-seller on that side of the pond with How to Teach Quantum Physics to…
esiegel | January 28, 2017"'Space-time' - that hideous hybrid whose very hyphen looks phoney." -Vladimir Nabokov
Sure, you know what space and time are. If you heard of Einstein and relativity, you might know that they’re not absolute quantities, but that how you experience distances and the ticking of clocks is dependent on your motion through the Universe. But did you also know that the addition of masses and gravitation to the theory didn’t just result in general relativity, but changed the way we viewed the Universe completely?
Quantum field theory calculations are normally done in flat space, but general…
esiegel | January 27, 2017"The way to love anything is to realize that it might be lost." -G. K. Chesterton
Worried about the environment of Earth today? Here’s a sobering fact: we already know how it’s all going to end. Not just when the next ice age will come or the next supervolcano will blow, but on cosmic scales stretching billions of years into the future and beyond. From the death of life on Earth to the end of the Sun, we can predict some major catastrophes our Solar System will face.
The Earth, if calculations are correct, should not be engulfed by the Sun when it swells into a red giant. It should, however…
esiegel | January 24, 2017"Work gives you meaning and purpose and life is empty without it." -Stephen Hawking
Throw a book into a black hole, and the information must somehow wind up inside. Same goes for a star, a planet, or even a single proton: that information must be maintained. But allow enough time to pass, and quantum theory and general relativity, combined, predict something troubling: that black hole will decay, and none of the information will come out in the decay products.
While Einstein's theory makes explicit predictions for a black hole's event horizon and the spacetime just outside, quantum…
esiegel | January 22, 2017“I hope that in this year to come, you make mistakes. Because if you are making mistakes, then you are making new things, trying new things, learning, living, pushing yourself, changing yourself, changing your world. You're doing things you've never done before, and more importantly, you're doing something.” -Neil Gaiman
Here we are, at the end of a momentous week here at Starts With A Bang! The world is changing; the president of the world's most powerful nation has changed; but the quest to learn ever more about the Universe still continues unabated. There's so much coming down the pipeline…
esiegel | January 21, 2017"It was a strange lightness, a drifting feeling. Zero gravity. I understood that everything that once seemed solid and immovable might just float away." -Lisa Unger
If you want to experience zero gravity, all you need to do is go to space, turn your rocket off and feel that weightless sensation, right? Except, from up there in Earth’s orbit, the gravitational force on you is still almost as great as it is on Earth’s surface! You still accelerate down towards the center of the Earth, not quite at 9.8 m/s^2, but not by much less.
Astronauts, and fruit, aboard the International Space Station.…
esiegel | January 18, 2017"There are now dozens of hockey sticks and the all come to the same basic conclusion. The recent warming does appear to be unprecedented as far bas as we can go. But even if we didn't have that evidence, we would still know that humans are warming the planet, changing the climate and that represents a threat if we don't do something about it." -Michael Mann
The latest climate science results are out, and 2016 was the hottest year on record. Again. Breaking the previous record... from 2015. Which broke the previous record of 2014. In fact, of the 17 hottest years on record, 16 of them have…
esiegel | January 15, 2017“Men go abroad to wonder at the heights of mountains, at the huge waves of the sea, at the long courses of the rivers, at the vast compass of the ocean, at the circular motions of the stars, and they pass by themselves without wondering.” -Saint Augustine
Well, another week has gone by -- the second of the year -- here at Starts With A Bang! Hopefully, none of you noticed a drop in the quality or frequency of the science I've been bringing you, because I've had the flu, but I've been working hard to make sure you get all the science you've come to expect. And it's been a tremendous week, with…
esiegel | January 14, 2017
"Lives are snowflakes - unique in detail, forming patterns we have seen before, but as like one another as peas in a pod (and have you ever looked at peas in a pod? I mean, really looked at them? There's not a chance you'd mistake one for another, after a minute's close inspection.)" -Neil Gaiman
When you see a snowflake, what you're seeing is a thin crystal of ice, with intricate, hexagonally-symmetric features that reveal themselves under a microscope. Although snowflakes come in a myriad of different shapes and patterns, there's one adage you've heard since you were a kid: that no two…
drorzel | January 13, 2017This one's late because I acquired a second class for the Winter term on very short notice. I was scheduled to teach our sophomore-level "Modern Physics" class, plus the lab, but a colleague who was scheduled to teach relativity for non-majors had a medical issue, and I'm the only other one on staff who's ever taught it, so now I'm doing two courses instead of one. Whee!
Anyway, here are my December posts from Forbes:
-- Science Is Not THAT Special: Another in a long series of posts grumbling about the way we set science off from other pursuits and act as if the problems facing it are unique…
gregladen | January 12, 2017A Fortunate Universe: Life in a Finely Tuned Cosmos
This is a concept that has always fascinated me, ever since reading some stuff about the Periodic Table of Elements. Check it out:
Over the last forty years, scientists have uncovered evidence that if the Universe had been forged with even slightly different properties, life as we know it - and life as we can imagine it - would be impossible. Join us on a journey through how we understand the Universe, from its most basic particles and forces, to planets, stars and galaxies, and back through cosmic history to the birth of the cosmos.…
esiegel | January 7, 2017“We are part of the universe that has developed a remarkable ability: We can hold an image of the world in our minds. We are matter contemplating itself.” -Sean Carroll
If you take a look at our Universe today, you can learn all sorts of things about it. How the matter in it is distributed, what the radiation is doing, how many and what types of black holes we’ve formed, how much entropy there is, etc. You can also learn how all of those things are evolving into the future and how they were different in the past!
The far distant fates of the Universe offer a number of possibilities, but if…
esiegel | January 5, 2017"The mystery about α is actually a double mystery. The first mystery – the origin of its numerical value α ≈ 1/137 has been recognized and discussed for decades. The second mystery – the range of its domain – is generally unrecognized." -Malcolm H. MacGregor
We assume that the fundamental constants are truly constant, but they don't have to be. The speed of light is the same everywhere, but it could have been different elsewhere, either in space or in time. The same is true for other constants, like Planck's constant, the gravitational constant, or even the fundamental charges or masses of…
esiegel | January 4, 2017“I have difficulty to believe it, because nothing in Italy arrives ahead of time.”
–Sergio Bertolucci, research director at CERN, on faster-than-light neutrinos
A little over five years ago, the OPERA collaboration announced an astounding result: that neutrinos sent through more than 700km of rock arrived at their destination 60.7 nanoseconds faster than they ought to. That was particularly disturbing, because the speed they ought to have arrived at was the speed of light, which nothing can move faster than. Either something very, very funny was going on with the experiment, or they had just…
esiegel | January 3, 2017"For me the best answer is not in words but in measurements." -Elena Aprile
Dark matter is perhaps the most mysterious substance in the Universe. It outmasses normal matter and radiation, which includes all the known particles in the Standard Model, by a factor of 5-to-1. The observational, astrophysical evidence for its existence is overwhelming, and there are a slew of direct detection efforts underway here on Earth. Depending on dark matter’s properties, any number of them might claim success at any point in the near future.
The cryogenic setup of one of the experiments looking to exploit…
oracknows | January 2, 2017Well, it's 2017. In a mere 17 days, unreality will become reality, as the most unlikely and terrifying President in my lifetime is sworn in. Consequently, as I was thinking about what I'd like to write about for my first post of the new year, only one thing came to mind. Only one thing that I routinely apply my Insolence, both Respectful and Not-So-Respectful, to achieves the level of unreality that our politics entered in November and will amplify in a little more than two weeks.
Yes, it's time for a reiki post.
OK, I admit it. A reader sent me a hilarious article about the mechanism of…
esiegel | December 31, 2016"It's a brilliant surface in that sunlight. The horizon seems quite close to you because the curvature is so much more pronounced than here on earth. It's an interesting place to be. I recommend it." -Neil Armstrong
There are many impressive optical phenomena that we can see with our own eyes here on Earth. The right configuration of raindrops or ice crystals can produce rainbows, shining light through a prism will separate it into its individual wavelengths, and from high altitudes in the pre-sunrise or post-sunset skies, a full spectrum of colors become visible.
From very high altitudes in…