That’s A Great Explanation Of Particle Physics XD
That’s a great explanation of particle physics xD
But really, this stuff is so interesting! I love reading about stuff like this - so good work NASA!
If you liked the four forces governing the universe, you might like this book I just finished reading for the seventh time (Neil DeGrasse Tyson’s “Astrophysics for People in a Hurry”). It talks about these forces and a lot of other really cool concepts, like dark energy and chemistry-related-to-space.
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May the Four Forces Be With You!
May the force be with you? Much to learn you still have, padawan. In our universe it would be more appropriate to say, “May the four forces be with you.”
There are four fundamental forces that bind our universe and its building blocks together. Two of them are easy to spot — gravity keeps your feet on the ground while electromagnetism keeps your devices running. The other two are a little harder to see directly in everyday life, but without them, our universe would look a lot different!
Let’s explore these forces in a little more detail.
Gravity: Bringing the universe together
If you jump up, gravity brings you back down to Earth. It also keeps the solar system together … and our galaxy, and our local group of galaxies and our supercluster of galaxies.
Gravity pulls everything together. Everything, from the bright centers of the universe to the planets farthest from them. In fact, you (yes, you!) even exert a gravitational force on a galaxy far, far away. A tiny gravitational force, but a force nonetheless.
Credit: NASA and the Advanced Visualization Laboratory at the National Center for Supercomputing and B. O'Shea, M. Norman
Despite its well-known reputation, gravity is actually the weakest of the four forces. Its strength increases with the mass of the two objects involved. And its range is infinite, but the strength drops off as the square of the distance. If you and a friend measured your gravitational tug on each other and then doubled the distance between you, your new gravitational attraction would just be a quarter of what it was. So, you have to be really close together, or really big, or both, to exert a lot of gravity.
Even so, because its range is infinite, gravity is responsible for the formation of the largest structures in our universe! Planetary systems, galaxies and clusters of galaxies all formed because gravity brought them together.
Gravity truly surrounds us and binds us together.
Electromagnetism: Lighting the way
You know that shock you get on a dry day after shuffling across the carpet? The electricity that powers your television? The light that illuminates your room on a dark night? Those are all the work of electromagnetism. As the name implies, electromagnetism is the force that includes both electricity and magnetism.
Electromagnetism keeps electrons orbiting the nucleus at the center of atoms and allows chemical compounds to form (you know, the stuff that makes up us and everything around us). Electromagnetic waves are also known as light. Once started, an electromagnetic wave will travel at the speed of light until it interacts with something (like your eye) — so it will be there to light up the dark places.
Like gravity, electromagnetism works at infinite distances. And, also like gravity, the electromagnetic force between two objects falls as the square of their distance. However, unlike gravity, electromagnetism doesn’t just attract. Whether it attracts or repels depends on the electric charge of the objects involved. Two negative charges or two positive charges repel each other; one of each, and they attract each other. Plus. Minus. A balance.
This is what happens with common household magnets. If you hold them with the same “poles” together, they resist each other. On the other hand, if you hold a magnet with opposite poles together — snap! — they’ll attract each other.
Electromagnetism might just explain the relationship between a certain scruffy-looking nerf-herder and a princess.
Strong Force: Building the building blocks
Credit: Lawrence Livermore National Laboratory
The strong force is where things get really small. So small, that you can’t see it at work directly. But don’t let your eyes deceive you. Despite acting only on short distances, the strong force holds together the building blocks of the atoms, which are, in turn, the building blocks of everything we see around us.
Like gravity, the strong force always attracts, but that’s really where their similarities end. As the name implies, the force is strong with the strong force. It is the strongest of the four forces. It brings together protons and neutrons to form the nucleus of atoms — it has to be stronger than electromagnetism to do it, since all those protons are positively charged. But not only that, the strong force holds together the quarks — even tinier particles — to form those very protons and neutrons.
However, the strong force only works on very, very, very small distances. How small? About the scale of a medium-sized atom’s nucleus. For those of you who like the numbers, that’s about 10-15 meters, or 0.000000000000001 meters. That’s about a hundred billion times smaller than the width of a human hair! Whew.
Its tiny scale is why you don’t directly see the strong force in your day-to-day life. Judge a force by its physical size, do you?
Weak Force: Keeping us in sunshine
If you thought it was hard to see the strong force, the weak force works on even smaller scales — 1,000 times smaller. But it, too, is extremely important for life as we know it. In fact, the weak force plays a key role in keeping our Sun shining.
But what does the weak force do? Well … that requires getting a little into the weeds of particle physics. Here goes nothing! We mentioned quarks earlier — these are tiny particles that, among other things, make up protons and neutrons. There are six types of quarks, but the two that make up protons and neutrons are called up and down quarks. The weak force changes one quark type into another. This causes neutrons to decay into protons (or the other way around) while releasing electrons and ghostly particles called neutrinos.
So for example, the weak force can turn a down quark in a neutron into an up quark, which will turn that neutron into a proton. If that neutron is in an atom’s nucleus, the electric charge of the nucleus changes. That tiny change turns the atom into a different element! Such reactions are happening all the time in our Sun, giving it the energy to shine.
The weak force might just help to keep you in the (sun)light.
All four of these forces run strong in the universe. They flow between all things and keep our universe in balance. Without them, we’d be doomed. But these forces will be with you. Always.
You can learn more about gravity from NASA’s Space Place and follow NASAUniverse on Twitter or Facebook to learn about some of the cool cosmic objects we study with light.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
More Posts from Acosmicgeek and Others
I love that
After my Life of Stars series I’ve been wanting to do one on galaxies. Maybe I will hmmmmm
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Galaxies: Types and morphology
A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. Galaxies range in size from dwarfs with just a few hundred million (108) stars to giants with one hundred trillion (1014) stars, each orbiting its galaxy’s center of mass.
Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the Hubble sequence.
Since the Hubble sequence is entirely based upon visual morphological type (shape), it may miss certain important characteristics of galaxies such as star formation rate in starburst galaxies and activity in the cores of active galaxies.
Ellipticals
The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter. Consequently, these galaxies also have a low portion of open clusters and a reduced rate of new star formation. Instead they are dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions.
Spirals
Spiral galaxies resemble spiraling pinwheels. Though the stars and other visible material contained in such a galaxy lie mostly on a plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of dark matter that extends beyond the visible component, as demonstrated by the universal rotation curve concept.
Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge.
Barred spiral galaxy
A majority of spiral galaxies, including our own Milky Way galaxy, have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies).
Ring galaxy
A ring galaxy is a galaxy with a circle-like appearance. Hoag’s Object, discovered by Art Hoag in 1950, is an example of a ring galaxy. The ring contains many massive, relatively young blue stars, which are extremely bright. The central region contains relatively little luminous matter. Some astronomers believe that ring galaxies are formed when a smaller galaxy passes through the center of a larger galaxy. Because most of a galaxy consists of empty space, this “collision” rarely results in any actual collisions between stars.
Lenticular galaxy
A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. They contain large-scale discs but they do not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks.
Irregular galaxy
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.
Dwarf galaxy
Despite the prominence of large elliptical and spiral galaxies, most galaxies in the Universe are dwarf galaxies. These galaxies are relatively small when compared with other galactic formations, being about one hundredth the size of the Milky Way, containing only a few billion stars. Ultra-compact dwarf galaxies have recently been discovered that are only 100 parsecs across.
Interacting
Interactions between galaxies are relatively frequent, and they can play an important role in galactic evolution. Near misses between galaxies result in warping distortions due to tidal interactions, and may cause some exchange of gas and dust. Collisions occur when two galaxies pass directly through each other and have sufficient relative momentum not to merge.
Starburst
Stars are created within galaxies from a reserve of cold gas that forms into giant molecular clouds. Some galaxies have been observed to form stars at an exceptional rate, which is known as a starburst. If they continue to do so, then they would consume their reserve of gas in a time span less than the lifespan of the galaxy. Hence starburst activity usually lasts for only about ten million years, a relatively brief period in the history of a galaxy.
Active galaxy
A portion of the observable galaxies are classified as active galaxies if the galaxy contains an active galactic nucleus (AGN). A significant portion of the total energy output from the galaxy is emitted by the active galactic nucleus, instead of the stars, dust and interstellar medium of the galaxy.
The standard model for an active galactic nucleus is based upon an accretion disc that forms around a supermassive black hole (SMBH) at the core region of the galaxy. The radiation from an active galactic nucleus results from the gravitational energy of matter as it falls toward the black hole from the disc. In about 10% of these galaxies, a diametrically opposed pair of energetic jets ejects particles from the galaxy core at velocities close to the speed of light. The mechanism for producing these jets is not well understood.
The main known types are: Seyfert galaxies, quasars, Blazars, LINERS and Radio galaxy.
source
images: NASA/ESA, Hubble (via wikipedia)
Well TECHNICALLY it’s a helium-4 nucleus
I guess I can see where the confusion comes from
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first post on Reddit lets go
Okay I love the Big Bang Theory (as in the actual scientific theory about the start of our universe) but also the TV show.
(Sheldon was my favorite)
Anyway I didn’t know there was a full version of the theme song and I really like it :)
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Neptune!
Mercury will always be my favorite planet (closest to the Sun, underappreciated, proved Einstein’s general relativity, among other things) but I think Neptune’s the most beautiful. Look at that hue!
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neptune.
Best Star Wars movie can’t deny it
Prequels and sequels eat your heart out
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The Empire Strikes Back opened in theaters on this day in 1980.
Tonight’s a New Moon!
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It’s been two years, and I’ll never forget him.
I remember when I was little and I loved space, but I was worried that I would be too bored of the astrophysics area. Then I read Mr. Hawking’s book a Brief History of Time, and I fell in love.
Thanks, Stephie.
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The world lost an amazing thinker today. Celebrated world-renowned physicist Stephen Hawking passed away in Cambridge on March 14th, 2018 (Pi Day), at age 76. Somehow, I think he would have found this to be very poetic.
Stephen William Hawking CH CBE FRS FRSA was an English theoretical physicist, cosmologist, author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge.
The search for another Earth is super cool even if it might never end lol
But like, Aliens.
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Are We Alone? How NASA Is Trying to Answer This Question.
One of the greatest mysteries that life on Earth holds is, “Are we alone?”
At NASA, we are working hard to answer this question. We’re scouring the universe, hunting down planets that could potentially support life. Thanks to ground-based and space-based telescopes, including Kepler and TESS, we’ve found more than 4,000 planets outside our solar system, which are called exoplanets. Our search for new planets is ongoing — but we’re also trying to identify which of the 4,000 already discovered could be habitable.
Unfortunately, we can’t see any of these planets up close. The closest exoplanet to our solar system orbits the closest star to Earth, Proxima Centauri, which is just over 4 light years away. With today’s technology, it would take a spacecraft 75,000 years to reach this planet, known as Proxima Centauri b.
How do we investigate a planet that we can’t see in detail and can’t get to? How do we figure out if it could support life?
This is where computer models come into play. First we take the information that we DO know about a far-off planet: its size, mass and distance from its star. Scientists can infer these things by watching the light from a star dip as a planet crosses in front of it, or by measuring the gravitational tugging on a star as a planet circles it.
We put these scant physical details into equations that comprise up to a million lines of computer code. The code instructs our Discover supercomputer to use our rules of nature to simulate global climate systems. Discover is made of thousands of computers packed in racks the size of vending machines that hum in a deafening chorus of data crunching. Day and night, they spit out 7 quadrillion calculations per second — and from those calculations, we paint a picture of an alien world.
While modeling work can’t tell us if any exoplanet is habitable or not, it can tell us whether a planet is in the range of candidates to follow up with more intensive observations.
One major goal of simulating climates is to identify the most promising planets to turn to with future technology, like the James Webb Space Telescope, so that scientists can use limited and expensive telescope time most efficiently.
Additionally, these simulations are helping scientists create a catalog of potential chemical signatures that they might detect in the atmospheres of distant worlds. Having such a database to draw from will help them quickly determine the type of planet they’re looking at and decide whether to keep observing or turn their telescopes elsewhere.
Learn more about exoplanet exploration, here.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
I love Schrodinger’s Cat memes
I might write something on quantum mechanics in the future, so I’ll probably dedicate an entire chapter to this cat. Maybe with a week’s worth of SC memes? Who knows!
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Erwin doesn’t like that.
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