esiegel | October 20, 2016“Man is something that shall be overcome. Man is a rope,tied between beast and overman - a rope over an abyss.What is great in man is that he is a bridge and not an end.” -Friedrich Nietzsche
There are only two types of singularities that General Relativity predicts the existence of in our Universe: one at the centers of black holes, which form from the collapse of matter, and one at the very birth of space and time, at the origin of it all. All of the information that falls into a black hole from our 3D Universe gets encoded on the black hole’s 2D event horizon, which is both fascinating and…
esiegel | October 19, 2016"In order for the light to shine so brightly, the darkness must be present." -Francis Bacon
If you had previously thought the Universe contained a certain amount of stuff, like stars, galaxies and matter, then you might think that learning it had ten times as many galaxies might mean it had ten times as much matter. And if this were the case for matter like us, made of protons, neutrons and electrons, perhaps there wouldn’t be a need for something like dark matter, after all.
The different shapes, structures and morphologies of some of the galaxies in Hickson Compact Group 59 show evidence…
esiegel | October 18, 2016"The supermoon is a 16-inch pizza compared with a 15-inch pizza. It's a slightly bigger moon; I ain't using the adjective 'supermoon.'" -Neil deGrasse Tyson
Earlier this month, the full Moon was the first "Supermoon" we've seen all year, where the bright full Moon coincided nearly perfectly with perigee, or the Moon's closest approach to Earth. Yet it won't be the last: November's and December's full Moons will also be Supermoons, appearing up to 14% bigger and 30% brighter than the full Moons from, say, March and April of this year.
A perigee full Moon compared with an apogee full Moon,…
esiegel | October 17, 2016“From our home on the Earth, we look out into the distances ... to imagine the sort of world into which we are born… . But with increasing distance our knowledge fades, and fades rapidly, until at the last dim horizon we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be suppressed.” -Edwin Hubble
Once thought to include anything that wasn’t a star, moon or planet in the night sky, our understanding of nebulae has grown tremendously over the centuries.…
esiegel | October 16, 2016“There are in fact 100 billion galaxies, each of which contain something like a 100 billion stars. Think of how many stars, and planets, and kinds of life there may be in this vast and awesome universe.” -Carl Sagan
And at long last, Carl Sagan's estimates are finally out of date. It's not ~100 billion galaxies, but a number more like two trillion, and at last we know! If you wanted to know what the topic of this month's Starts With A Bang podcast was going to be, there's your answer! Look for it sometime over the next two weeks. Of course, none of that has changed what we write about here at…
esiegel | October 15, 2016“Honestly, if you’re given the choice between Armageddon or tea, you don’t say ‘what kind of tea?” -Neil Gaiman
Between the near-Earth asteroids that orbit close by our planet, and the distant comets that plunge periodically into the inner Solar System, Earth has plenty to be concerned about over the long haul. A slight gravitational nudge to any of those objects could put them on a collision course for our world. Thankfully, we can see them and track them, and calculate exactly how big of a threat they are to us.
Comet Lovejoy, as seen from the International Space Station, poses no threat…
esiegel | October 14, 2016“Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.” -Carl Sagan
How many galaxies are there in the observable Universe? If you had asked this question a century ago, the answer could have been anywhere from one to infinity. If you asked fifty years ago, we’d know the number was finite, since we knew about…
esiegel | October 13, 2016“Scratch a cynic and you'll find a disappointed idealist.” -Jon F. Merz
The stars overhead might twinkle and cause us to wonder what they are, exactly, but perhaps a more important question is to wonder where they are. If we can determine the distances to the stars, and then use those known distances to measure the distances to other galaxies, we can not only determine how far away they are, but determine how the Universe has expanded over the course of its cosmic history.
The construction of the cosmic distance ladder involves going from our Solar System to the stars to nearby galaxies to…
esiegel | October 12, 2016"Thus is our treaty written; thus is agreement made. Thought is the arrow of time; memory never fades. What was asked is given; the price is paid." -Robert Jordan
Why does time flow forwards and not backwards, in 100% of cases, if the laws of physics are completely time-symmetric? From Newton's laws to Einstein's relativity, from Maxwell's equations to the Schrödinger equation, the laws of physics don't have a preferred direction. Except, that is, for one: the second law of thermodynamics. Any closed system that we look at sees its entropy only increase, never decrease.
A system set up in…
esiegel | October 11, 2016"Each ray of light moves in the coordinate system 'at rest' with the definite, constant velocity V independent of whether this ray of light is emitted by a body at rest or a body in motion." -Albert Einstein, 1905
The idea of relativity, that there's no "absolute rest frame" where the laws of physics are special, has been around since Galileo. If you think about a moving train firing a cannonball, that's Galilean relativity: a person on the train would see the cannonball move at a different speed from a person on the ground.
A French 320 mm railway gun, used during World War I.
But if you…
esiegel | October 10, 2016"They most likely form as subsystems within looser associations and evolve by gravitational processes. Strong galaxy interactions result and merging is expected to lead to the ultimate demise of the group. Compact groups are surprisingly numerous, and may play a significant role in galaxy evolution." -Paul Hickson
With hundreds of billions of galaxies in an observable Universe nearly 100 billion light years across, it should come as no surprise that most galaxies are separated by millions of light years from their next-nearest neighbor. Yet even outside of dense galaxy clusters, large numbers…
esiegel | October 9, 2016“Life and death matters, yes. And the question of how to behave in this world, how to go in the face of everything. Time is short and the water is rising.” -Raymond Carver
As we make our way through October, Halloween approaches here at Starts With A Bang! But as eerie as the world and our Universe might be, our goal is always to shed a little light into how we know the things we do, and what the possibilities beyond our knowledge might be. Take a look back on this past week in case you missed anything:
Why don't we shoot Earth's garbage into the Sun? (for Ask Ethan),
Astronomy's dark horse…
esiegel | October 8, 2016"There have to be moments when you glimpse something decent, something life-affirming even in the most twisted character. That's where the real art lies." -Martin McDonagh
There is a whole lot of cosmic detective work we can do to figure out the history of the Solar System. By examining the fossil record, geological deposits, the surface of other planetary bodies, meteors, asteroids and comets, the physics of the Sun, and the various components and layers of Earth, we can reconstruct when and where our planet and the rest of the Solar System came from.
A massive collision of large…
esiegel | October 7, 2016“What is wild cannot be bought or sold, borrowed or copied. It is. Unmistakeable, unforgettable, unshamable, elemental as earth and ice, water, fire and air, a quintessence, pure spirit, resolving into no constituents.” -Jay Griffiths
At the earliest times, we can trace the history of our Universe back to an inflationary state, where the energy inherent to space itself caused a rapid, exponential expansion. At the latest (current) times, billions of years after inflation ended and the Big Bang occurred, dark energy has come to dominate the Universe’s expansion. These two states are very…
esiegel | October 6, 2016"You are both fools. You cannot see thoughts, or angels. One is an abstract, the other a fantasy. To compare the two would be silly. Of course, using inferential logic, we can detect the existence of thought by the evidence of its actions, just as I detected the existence of a new form of radiation! Seeing no evidence of God or angels, and applying Occam’s Razor we can effectively rule out God or angels with metaphysical certainty. By the way Mr. Astronaut, you have cancer." -Pavel Cherenkov (allegedly)
It’s true that nothing can move faster than the speed of light, but only if you’re in a…
esiegel | October 5, 2016“She didn’t even know what she’d do when she got back to New Orleans, but inside she felt a yearning to shove her hands in the dirt, to cling to the ground there, forever.” -Sarah Rae
Hurricanes are among the most destructive natural disasters to occur on Earth, with extensive flooding, property damage and loss of life commonly accompanying them. But they’re also inevitable consequences -- at least on our world -- of two simple factors: warm ocean waters and winds.
The formation of a hurricane relies on warm, humid air, winds, and pressure changes. Image credit: NASA's SciJinks, via http://…
esiegel | October 4, 2016"'Topology is destiny,' he said, and put the drawers on. One leg at a time." -Neal Stephenson
If you want to understand the Universe, there are two big areas you need to know: Einstein’s theory of general relativity, which governs the gravitational force and the curvature of spacetime, and quantum physics, which governs all the particles, the states of matter and every non-gravitational interaction ever. While many were expecting the Nobel Prize to go to the LIGO collaboration for the groundbreaking first direct detection of gravitational waves, there are a slew of quantum discoveries that…
esiegel | October 3, 2016"If you are fearful, a horse will back off. If you are calm and confident, it will come forward. For those who are often flattered or feared, the horse can be a welcome mirror of the best in human nature." -Clare Balding
One of the most iconic astronomy images is that of the Horsehead Nebula. Located just off the easternmost star along Orion’s Belt, the Horsehead is remarkable for being a “dark” nebula rather than emitting or reflecting light on its own. This is due to its dust-rich nature and the background emission nebula, caused by bright, young stars that ionize the gaseous interstellar…
esiegel | October 2, 2016“Put two ships in the open sea, without wind or tide, and, at last, they will come together. Throw two planets into space, and they will fall one on the other. Place two enemies in the midst of a crowd, and they will inevitably meet; it is a fatality, a question of time; that is all.” -Jules Verne
As the final three months of the year begin, it’s again time to look back on the past week here at Starts With A Bang! Lots of exciting stories were met with a number of interesting and provocative comments, which is what I always like to see. Here's what we covered, in case you missed anything:…
esiegel | October 1, 2016"There will be peace when the people of the world, want it so badly, that their governments will have no choice but to give it to them. I just wish you could all see the Earth the way that I see it. Because when you really look at it, it's just one world." -Superman
So, you want to shoot Earth’s garbage into the Sun, do you? From a physics point-of-view, this is difficult, but possible. First, you have to overcome the pull of Earth’s gravity, and escape into space. Next, you have to take into account the fact that Earth orbits the Sun at 30 km/s, and to fall into the Sun, you need to take…