Paradox Explained

Hello, lovely people of Earth and beyond! My name is Whitney. I am merely a high school student with a blog. Mine just happens to be of the scientific variety. I have a passion for astrophysics and quantum physics, and will teach astrophysics at the collegiate level in the future. Feel free to leave questions and/or comments in my ask box.


"Here it is standing: atoms with consciousness; matter with curiosity.
Stands at the sea, wondering: I… a universe of atoms
...an atom in the universe."

— Richard Feynman

ibmblr:

Way, way back in the 1990s, stores knew you and what you liked. Then online shopping came along and many mom-and-pops closed up shop. In 5 years, the little guys will have fought back to give online retail a taste of its own medicine.  See your life in five years…

I hope that you all are excited to view the Perseid Meteor Shower! The Perseids whiz across the night sky every August, and the peak of this particular shower is going on right now! (August 11-13) The best time for viewing is between midnight and dawn.

Happy viewing Earth dwellers! Feel free to submit any pictures you take during the meteor shower! I will publish them on here, for everyone to enjoy!

we-are-star-stuff:

Why is gravity so weak?

While the other fundamental forces of nature (electromagnetic force, weak nuclear force and strong nuclear force) are constrained to our three-dimensional world, gravity is thought to be free to propagate in extra dimensions, so its effect in our three-dimensional world is somewhat diluted. Hence we see it as being weak since it is thinly spread over all the dimensions, whereas its strength is probably comparable to the other forces.

When we say that gravity is much weaker than the other forces we mean that its coupling constant is much smaller than the coupling constants of other forces. Think about a coupling constant as a parameter that says how much energy there will be in per “unit of interacting stuff”. This is a very rough definition but it will serve our purpose.

If you determine the coupling constants of all different forces, you discover that, in decreasing order, strong, eletromagnetic and weak forces are much, much stronger than gravity. Moreover, the difference between strong, weak and electromagnetic forces among themselves isn’t nearly as extreme as the difference between gravity and the other forces.

In a hydrogen molecule gravity pulls the two protons together with a force about 36 powers of ten weaker than the electric force between them. But in any large object, positive and negative electric charges almost cancel out. In contrast, everything has the same sign of gravitational charge, so gravity inexorably gains importance in large objects. What does it take for gravity to win?

The answer involves some arithmetic- but nothing complicated. Suppose you assemble progressively larger lumps containing 10, 100, 1000 atoms, and so on. The 24th would be the size of a sugar lump; the 40th would be the size of a mountain or a small asteroid.

The effect of gravity on each atom - how strongly gravity binds it to all the others in the lump - goes up in proportion to the total number of atoms but down by their average distance from each other. For each 1000-fold increase in mass, the importance of gravity goes up 100 fold. This is because, though the number of atoms goes up by 1000, their average distance from each other goes up by 10. Despite its initial handicap, amounting to 36 powers of 10, gravitational forces becomes dominant when more than about 10 to the power 54 protons are packed together (36 being two thirds of 54) - that’s a number that can be written as one followed by 54 zeros. This mass is about the same as that of Jupiter, the biggest planet in our Solar System. To become a star, a body must be about a hundred times more massive still - so that it can hold itself together, gravitationally, even when its center is hot enough for nuclear fusion to occur.

Gravity eventually wins - but because it is so weak it only triumphs on very large scales. The Princeton physicist Robert Dicke was the first to emphasize the key point that stars are so big because gravity is so weak - because the ratio of the electrical and gravitational forces within atoms is such a huge number. Dicke also estimated the time it takes for heat to diffuse out of a star, showing that this time is long, implying that stars have long lives as well as being big, because this same ratio is so large.

It’s amusing to ask what the universe would be like if gravity weren’t quite so weak. Suppose, for example, that gravity was ‘only’ 26 rather than 36 powers of ten weaker than electric forces in atoms - but the properties of the atoms themselves were unchanged. Atoms and molecules would behave just as in our actual universe, but objects would not need to be so large before gravity became competitive with the other forces. In this imagined universe stars would contain a million billion times fewer particles than the sun does. If these stars had planets around them, they would be smaller than the actual planets in our Solar System by the same factor, but gravity on their surfaces would pull far more strongly than on Earth. Strong gravity would crush anything larger than an insect on hypothetical miniplanets around these miniSuns. But more severe still is the limited time. Instead of living for 10 billion years, a miniSun would last for about 1 year. and would have exhausted its energy before even the first steps in organic evolution had got under way. The actual scaling isn’t quite this simple: mini-stars in this strong-gravity universe would, for instance, have somewhat hotter surfaces than actual stars. But the outlook for complex evolution would plainly be less propitious, because there is less space and less time for its operation. Any creatures bigger than insects living on a planet with an atmosphere, would be crushed by gravity.

There would be fewer powers of 10 between the lifetime of stars and the basic microphysical timescales for physical or chemical reactions so no such creatures could have had time to emerge via evolution anyway.

If gravity weren’t so weak, the universe couldn’t contain such a multilayered hierarchy of structures, and wouldn’t allow time for complex evolution. So gravity is crucial in the cosmos - but the weaker it is (provided it isn’t zero) the grander and more complex can be its manifestations.

Sources: 1 2 3 4

(via space-tart)

spaceplasma:

Electric discharge showing the lightning-like plasma filaments from a Tesla coil.
GIF from photos courtesy of  Dan McCauley

spaceplasma:

Electric discharge showing the lightning-like plasma filaments from a Tesla coil.

GIF from photos courtesy of Dan McCauley

(via thescienceofreality)

CERN will open its doors to the general public over two days and not just one as it was the case in 2004  and 2008.  

There is a great deal of interest in what is happening at CERN so we expect a very large number of visitors.

As there are only a limited number of visit points, spreading the visits over two days will give many more people a chance to experience the fascinating things on show.

We have also extended the opening hours to 09:00-20:00 each day.

(via thescienceofreality)

thenewenlightenmentage:

Magnetar Found at Giant Black Hole

Magnetized neutron star could test Einstein’s theory.

Dale Frail couldn’t resist the prospect of watching a black hole swallow its prey. Frail, who is in charge of the Very Large Array (VLA) of radio telescopes near Socorro in New Mexico, had seen a report last month about a long-lived X-ray flare emanating from the centre of the Milky Way, home to a supermassive black hole called Sagittarius A* (Sgr A*). Astronomers were speculating that the flare might be a sign that a gas cloud they had been tracking had begun its death spiral into the black hole.

Continue Reading

(via thescienceofreality)

For the past couple of weeks, I have been consumed by the hysteria surrounding the AP Physics exam. Studying, studying, and studying some more became my life, to the point that blogging was nearly impossible. For weeks, I put aside the life I enjoy within Tumblr’s science community. I can finally, finally, say that “I’m baaaaaack!” Send in any topics you would like me to write about, or any videos you would like me to feature on this blog!

jtotheizzoe:

Happy Earth Day, everyone. Take care of it, it’s the only one we’ve got (at least until Rose and The Doctor introduce us to New Earth in a few billion years).

It’s always a good time to celebrate how wonderful our planet is, but this day especially. And there’s no better tribute than this animated adaptation of Carl Sagan’s Pale Blue Dot by Ehdubya, right?

And because I love you guys, here’s another animated “Pale Blue Dot”, from ORDER animation:

(via astronomerinprogress)

thescienceofreality:

NASA Selects 2013 Carl Sagan Fellows

NASA has selected five planet hunters to receive the 2013 Carl Sagan Exoplanet Postdoctoral Fellowships. The fellowship, named for the late astronomer, was created to inspire the next generation of explorers seeking to learn more about planets, and possibly life, around other stars. 

The primary goal of the fellowship program is to support outstanding recent postdoctoral scientists in conducting independent research related to the science goals of NASA’s Exoplanet Exploration Program. 

Significant discoveries have already been made by previous Sagan Fellows. One recent discovery found that the size and location of an asteroid belt may determine whether complex life will evolve on an Earth-like planet . 

“In the past decade, astronomers have made incredible progress toward Carl Sagan’s goal of understanding the existence of life, and ultimately, of intelligent life throughout the universe,” said Charles Beichman, executive director of the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena. The young scientists named as this year’s Sagan Fellows will help to make dramatic new progress toward this goal through their observational, theoretical and instrumental contributions.” 

The program, created in 2008, awards selected postdoctoral scientists with annual stipends of $65,500 for up to three years, plus an annual research budget of up to $16,000.

The 2013 Sagan Fellows are as follows [in order from left to right]:


— Jared Males, who will work at the University of Arizona, Tucson, to investigate exoplanetary habitability by perfecting instrumentation to image Jupiter- and Saturn-sized planets in the liquid- water habitable zone of nearby stars. 

— Katja Poppenhaeger, who will work at the Harvard Smithsonian Center for Astrophysics, Cambridge, Mass., to explore how stars and close-in planets influence each other’s evolution over time. 

— Jacob Simon, who will work at the Southwest Research Institute, San Antonio, to understand the formation of planets out of gas and dust disks. 

— Jennifer Yee, who will work at the California Institute of Technology, Pasadena, Calif., to measure the frequency of massive planets around low mass stars using microlensing. 

— Avi Shporer, who will work at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., to find massive extrasolar planets that do not transit their parent stars. 

NASA has two other astrophysics theme-based fellowship programs: the Einstein Fellowship Program, which supports research into the physics of the cosmos, and the Hubble Fellowship Program, which supports research into cosmic origins. The Sagan Fellowship Program is administered by the NASA Exoplanet Science Institute as part of NASA’s Exoplanet Exploration Program at JPL. Caltech manages JPL for NASA.”

  • A full description of the 2013 fellows and their projects, and other information about these programs is available here
  • More information about the NASA Exoplanet Science Institute is available here
  • More information about NASA’s Astrophysics Division is here.
A blade of grass is a commonplace on Earth; it would be a miracle on Mars. Our descendants on Mars will know the value of a patch of green. And if a blade of grass is priceless, what is the value of a human being?
Carl Sagan

discoverynews:

Dark Matter Found? Orbital Experiment Detects Hints

Around 400,000 positron detections have been confirmed in this first batch of data — positrons that are of energies consistent with the signature of dark matter annihilation.


 

Maria Mitchell (1818-1889)


Maria Mitchell, the first recognized female astronomer and college professor, was born into a large Quaker family on August 1, 1818. The Mitchell family stressed the importance of education to their children, including the girls.

Maria’s father was a schoolteacher with a passion for astronomy. The family owned a 2-inch reflecting telescope, with which Maria and her siblings assisted their father with various observations.

On the night of October 1, 1847, Miss Mitchell peered into her telescope and caught sight of a comet. Now, at the time, identifying new comets was considered a very prestigious achievement. It was in fact rewarded with a medal from King Frederick VI of Denmark. So, when Maria Mitchell discovered this new celestial body, she was instantly awarded with international notoriety and a plethora of honors.

Maria Mitchell became the first woman elected to membership in the American Academy of Arts and Sciences. She was a fellow of the American Academy for the Advancement of Science as well. The comet for which her initial success was attributed was named, “Miss Mitchell’s Comet.”

Throughout her career, Mitchell observed sunspots, comets, nubulae, solar eclipses, and countless other astronomical bodies. She went on to become a professor at Vassar College, thus making her the first woman teaching astronomy at the collegiate level.

Maria Mitchell passed away in 1889 from a brain disease. There is a crater on the moon in her name.

Although unfamiliar to most in the modern day, Mitchell was highly respected amongst her contemporaries. She is a noteworthy woman in STEM, an inspiration to the young ladies of today.

"We have a hunger of the mind which asks for knowledge of all around us, and the more we gain, the more is our desire; the more we see, the more we are capable of seeing.”

-Maria Mitchell

"I would as soon put a girl alone into a closet to meditate as give her only the society of her needle."

-Maria Mitchell

distant-traveller:

Unusual starburst galaxy NGC 1313

Why is this galaxy so discombobulated? Usually, galaxies this topsy-turvy result from a recent collision with a neighboring galaxy. Spiral galaxy NGC 1313, however, appears to be alone. Brightly lit with new and blue massive stars, star formation appears so rampant in NGC 1313 that it has been labeled a starburst galaxy. Strange features of NGC 1313 include that its spiral arms are lopsided and its rotational axis is not at the center of the nuclear bar. Pictured above, NGC 1313 spans about 50,000 light years and lies only about 15 million light years away toward the constellation of the Reticle (Reticulum). Continued numerical modeling of galaxies like NGC 1313 might shed some light on its unusual nature.

Imag credit: Robert Gendler

(via anndruyan)

fostertheory:

Neil deGrasse Tyson (an astrophysicist who has also appeared in the comics, albeit with the Distinguished Competition), on “How to Become an Astrophysicist”

The most beautiful experience we can have is the mysterious - the fundamental emotion which stands at the cradle of true art and true science.
Albert Einstein