“A sense of wonder is not our only starting point. It can also be our destination.”

Sharman Apt Russell | Anatomy of A Rose: Exploring the Secret Life of Flowers

Lanzamiento del Skylab (NASA).

(Source: astroperlas, via space-pics)

Sharon Johnstone - Macro (2012)

(Source: likeafieldmouse.com, via dendroica)

New principle may help explain why nature is quantum

Like small children, scientists are always asking the question ‘why?’. One question they’ve yet to answer is why nature picked quantum physics, in all its weird glory, as a sensible way to behave. Researchers Corsin Pfister and Stephanie Wehner at the Centre for Quantum Technologies at the National University of Singapore tackle this perennial question in a paper published today in Nature Communications.

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(Source: thenewenlightenmentage, via thenewenlightenmentage)

X-ray vision tracks lightning bursts

Blink and you’ve missed it. Researchers in the US have captured the world’s first X-ray images of lightning, by creating a special camera that can capture radiation at 10 million frames per second. They presented their new findings at the American Geophysical Union (AGU) Fall Meeting in San Francisco and they say that this new view of lightning could help to solve some of the mysteries of this spectacular natural phenomenon.

The research was carried out at the International Center for Lightning Research and Testing, located in Florida. It is one of the few sites in world where lightning is initiated and studied under controlled conditions. By firing rockets with trailing wires into thunder clouds, scientists are able to generate electric fields that are large enough to trigger bolts of lightning, which then propagate back down towards the rocket launch tower.

Joseph Dwyer and colleagues at the Florida Institute of Technology became interested in the fact that lightning emits X-rays as it propagates through the air, a phenomenon that was only noted in the past decade. But given that X-ray sources in lightning travel through the Earth’s atmosphere at velocities approaching the speed of light, it is difficult to catch them on camera before they disappear. In addition, they cannot be imaged with standard mirrors and lenses because huge amounts of material are required to prevent X-rays and gamma rays from entering through the sides of a camera.

Dwyer’s team has created a customized camera that has 30 detectors made from a combination of sodium iodide and photomultiplier tubes, each measuring 3 × 3 inch. The device, which is approximately the size of a standard refrigerator, is also equipped with a 3 inch pinhole aperture, and can record X-rays at 10 million frames per second. “This is actually a very old technique for making images, like that seen in a camera obscura,” Dwyer says.

During July and August this year, Dwyer’s team studied four rocket-triggered lightning flashes at the Florida test site. Each flash lasted for approximately two seconds and the resulting sequences of images revealed that X-rays emerged primarily from the vicinity of the lightning tip as it propagated towards the Earth. As the lightning crashed into the control tower it also triggered large bursts of gamma radiation, which were also captured by the camera.

“For the first time we’re catching a glimpse of lightning in the X-ray emission,” says Dwyer. “We’re seeing lightning as Superman would see it with his X-ray vision”.

Credit: James Dacey/physicsworld.com

(Source: spaceplasma, via n-a-s-a)

Follow this little Feynman Factoid up with TED Ed’s animated video about just how small an atom really is.

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Roberto Longo

(Source: kateoplis)

(Source: jereblog, via invaderxan)

Physics in the Gravity Trailer | by RHETT ALLAIN (Wired)

Let’s take a look at this trailer for the upcoming movie Gravity. I don’t know much, but it seems like it is about two astronauts dealing with some problems on the International Space Station. After watching this, my physics alert system went off. It might be a false alarm, so I will take a closer look.

Orbit Altitude

If you look at the Wikipedia page on the ISS, it lists the orbit altitude at 250 to 263 miles above the Earth. Here is a shot from the trailer.

Ok. I don’t know for certain this is the ISS in the trailer. I assume it is, but it could be some new space station. However, at “372 miles above the Earth” the ISS is much higher than it normally operates. I guess that’s ok – I mean this is a fictional story. I don’t see any reason why it couldn’t be this high. I just don’t see why they would significantly change the altitude. Maybe there is some plot element regarding the altitude – but if not, this is just sad. Really, it isn’t difficult to look up the orbital characteristics of the ISS.

Well, there is one big difference with an increased altitude. The orbital period would be longer. Maybe that is important in the plot. Maybe.

Air Resistance in Orbit

This is a short trailer with short clips of things. This means that it’s not quite clear what’s going on in each scene. Let’s look at a few.

This shows part of the ISS exploding for some reason. I think this short clip is ok in that it has the debris expanding in all directions.

In this scene, there is stuff that is clearly getting pushed back by air. At a 372 mile altitude, there is still air – but very little. Even at the ISS’s current orbit, there is air resistance – and this is why the space station occasionally needs a reboost. But at that height, the air resistance wouldn’t do anything like this. The next scene shows material leaving trails, so perhaps the space station got much closer to the Earth.

Here is an astronaut hanging on to the ISS.

If you are just flying past the space station and you grab on to stop yourself, that would be it. You would stop. You wouldn’t keep getting pulled back. If the space station was low in the orbit with significant air resistance, then that could happen. However, I have a feeling that you would have to be pretty low to get some serious forces as depicted in this scene.

Homework

Clearly, I don’t have any definite answers here. So, instead I will give homework questions. That’s what I do.

Estimate the drag force on the ISS at its current orbit altitude. Here is a hint. If you increased the altitude to 327 miles, how would the air drag force change?

What would the density of air have to be for an astronaut to experience an air drag force of about half the astronaut’s weight on the surface of the Earth?

Suppose re-entry starts at an altitude of 200 miles (I just guessed). What is the change in energy (both kinetic and gravitational potential) for an ISS going from an altitude of 372 miles to 200 miles? (sorry for using miles – but that’s what it lists in the video).

Let me point out one more thing. Why did I even start this post in the first place? After my first pass of the trailer, I was afraid that there was a very wrong misconception. The common idea is that when you knock something off of a fast moving object, that knocked off thing will slow down. This is indeed what happens to a fast moving air plane. The debris falls back due to an interaction with the air. However, in high orbits the air drag is quite small. This means that if you knock something off the ISS, it will basically just stay there.

After examining the trailer again, I’m not sure this problem is in the short clip. It seems that all of the objects moving past the ISS are due to some type of re-entry. I guess I will have to wait for the movie or another trailer to really find out what is going on.

The physics of beauty requires math. The sunflower has spirals of 21, 34, 55, 89, and - in very large sunflowers - 144 seeds. Each number is the sum of the two preceding numbers. This pattern seems to be everywhere: in pine needles and mollusk shells, in parrot beaks and spiral galaxies. After the fourteenth number, every number divided by the next highest number results in a sum that is the length-to-width ratio of what we call the golden mean, the basis for the Egyptian pyramids and the Greek Parthenon, for much of our art and even our music. In our own spiral-shaped inner ear’s cochlea, musical notes vibrate at a similar ratio.

The patterns of beauty repeat themselves, over and over. Yet the physics of beauty is enhanced by a self, a unique, self-organizing system. Scientists now know that a single flower is more responsive, more individual, than they had ever dreamed. Plants react to the world. Plants have ways of seeing, touching, tasting, smelling, and hearing.

Rooted in soil, a flower is always on the move. Sunflowers are famous for turning toward the sun, east in the morning, west in the afternoon. Light-sensitive cells in the stem “see” sunlight, and the stem’s growth orients the flower. Certain cells in a plant see the red end of the spectrum. Other cells see blue and green. Plants even see wavelengths we cannot see, such as ultraviolet.

Most plants respond to touch. The Venus’s-flytrap snaps shut. Stroking the tendril of a climbing pea will cause it to coil. Brushed by the wind, a seedling will thicken and shorten its growth. Touching a plant in various ways, at various times, can cause it to close its leaf pores, delay flower reproduction, increase metabolism, or produce more chlorophyll.

Plants are touchy-feely. They taste the world around them. Sunflowers use their roots to “taste” the surrounding soil as they search for nutrients. The roots of a sunflower can reach down eight feet, nibbling, evaluating, growing toward the best sources of food. The leaves of some plants can taste a caterpillar’s saliva. They “sniff” the compounds sent out by nearby damaged plants. Research suggests that some seeds taste or smell smoke, which triggers germination.

The right sound wave may also trigger germination. Sunflowers, like pea plants, seem to increase their growth when they hear sounds similar to but louder than the human speaking voice.

In other ways, flowers and pollinators find each other through sound. A tropical vine, pollinated by bats, uses a concave petal to reflect the bat’s sonar signal. The bat calls to the flower. The flower responds.

Sharman Apt Russell | Anatomy of A Rose: Exploring the Secret Life of Flowers [x]

“A house that’s neglected is a house that may be doomed in the atomic age.”

Read: In 1954, Americans Were Told to Paint Their Houses to Increase Their Chances of Surviving an Atomic Bomb

(Source: theatlanticcities, via theatlantic)

When a drop falls from a moderate height into a shallow pool, its impact creates a complicated pattern. The photo above is a composite image showing a top-down view 100 ms after such an impact. On the left side, the flow is visualized using dye whereas the right shows a schlieren photograph, in which contrast indicates variations in density. Both methods show the same general structure - an inner vortex ring generated at the edge of the impact crater and formed mostly of drop fluid and an outer vortex ring, consisting primarily of pool fluid, formed by the spreading wave. Both regions show signs of instability and breakdown. (Photo credit: A. Wilkens et al.)

(via fuckyeahfluiddynamics)

How do telescopes let us see so far into space?

Everything you need to know about how telescopes work.

Why is your eye so bad at seeing things far away?

Human eyes can see long distances. In fact the Andromeda Galaxy can be seen with the naked eye and that’s 2.5 million light-years away. But even a massive galaxy, like Andromeda, appears to us as a tiny point in the sky.

It makes sense that as an object gets further away it becomes harder to see. But why this happens helps us understand how vital telescopes have been in exploring the universe.

As an object gets further away less of its light will reach your eye. The image takes up less space on your retina (the light-sensitive tissue at the back of your eye), making the image smaller. This makes details of the image harder to see.

Do bigger lenses give us a bigger image?

To make a distant object appear brighter and larger, we effectively need a bigger eye to collect more light. With more light we can create a brighter image, we can then magnify the image so that it takes up more space on our retina.

The big lens in the telescope (objective lens) collects much more light than your eye can from a distant object and focuses the light to a point (the focal point) inside the telescope.

A smaller lens (eyepiece lens) takes the bright light from the focal point and magnifies it so that it uses more of your retina.

A telescope’s ability to collect light depends on the size of the objective lens, which is used to gather and focus light from a narrow region of sky.

The eye piece magnifies the light collected by the objective lens, like a magnifying glass magnifies words on a page. But the performance of a telescope depends almost entirely on the size of the objective lens, sometimes called the aperture.

What’s the big problem with refracting telescopes?

If you’ve ever seen light bend through a prism you probably have an idea of where the problem lies with a refracting telescope; it’s the lens.

When light travels through glass it slows down, that’s why it bends. Lenses are shaped perfectly to bend light in particular ways. But the amount light bends depends on the wavelength, or colour, of the light.

White light is a mixture of all colours, from red to violet. Red light bends the least and violet light bends the most.

When white light travels through the objective lens, the different colours bend at different angles and are focused at slightly different points. Different coloured images are misaligned creating a blurry image with fringes of colour along the boundaries that separate dark and bright parts.

Can telescopes with mirrors correct the problem?

Reflecting telescopes magnify distant objects using the same principle: more light is collected and focused to a point and this is magnified so that it fills your field of vision.

But instead of using a lens, a curved mirror (primary mirror) collects the light and reflects it to a focus. Because light doesn’t pass through the mirror, it doesn’t bend the different colours by different amounts, the way a refracting lens does.

A small mirror (secondary mirror) is placed in the path of light from the primary mirror to reflect the image towards the eyepiece. The secondary mirror must be very small so that it doesn’t block the light from the distant object as it travels to the primary mirror.

Another benefit of using mirrors instead of lenses is that big mirrors are easier and cheaper to make than big lenses. Reflecting telescopes can be much larger and therefore look deeper into space.

Are radio telescope like big reflecting telescopes?

Radio waves aren’t just for listening to your favourite songs, they occur naturally all over the universe. In fact, they are a special type of light that humans can’t see. They can be found emanating from clouds of gas where stars are born, as well as the centres of galaxies.

Many strong sources of radio waves are invisible in normal light, so looking at radio waves reveals a completely different picture of our universe. Even objects like the Sun and planets can reveal new features when viewed with radio telescopes, like Jodrell Bank.

Radio waves are also better at travelling long distances than shorter wavelengths, so we can get clearer signals from very distant objects in radio than we can in normal light.

The large dish acts like the primary mirror in a reflecting telescope, but it needs to be much larger to reflect the long wavelength radio waves. These are reflected up to a smaller mirror which reflects the images back to a receiver. The information from the receiver is then processed by computers to create colour images which we can see.

Source: BBC.co.uk

(Source: stellar-indulgence)

Plasma ball

The graceful purple arcs of plasma dancing in a plasma ball are created by a large alternating voltage at its centre, and that alternating voltage creates an electromagnetic field with which we can light a fluorescent tube.

At the centre of a plasma ball is a large alternating voltage, typically a few kilovolts oscillating at around 30 kHz. The low density of the gas in the globe (often neon) makes discharge significantly more favourable than it is in air at atmospheric pressure (the breakdown voltage of air which causes sparks from a Van de Graaff generator, for example, is 30,000 V/cm, whilst this can create arcs many centimetres long with just a few thousand volts). These fronds of plasma make their way from the centre of the globe to the edge, in a bid to reach earth. Creating an enhanced path to earth by touching the globe increases the strength of the discharge, which is why the arcs are attracted to your hand if you touch the globe.

The alternating voltage at the centre creates electromagnetic waves, and the arcs of plasma act as antennae, meaning that the extent of the electromagnetic field surrounding the ball is significantly larger than the bounds of the glass globe. Bringing the fluorescent tube near to the plasma ball allows the electrons inside to be accelerated by this field, and those moving electrons constitute an electric current, which causes the bulb to light up.

This demonstrates that an electromagnetic wave can be used to accelerate particles, providing an alternative to the large, static voltages supplied by Van de Graaff generators. In a real particle accelerator, radio-frequency, or RF, cavities are used to give the particles a kick with an electromagnetic standing wave.

(Source: spaceplasma, via crumblybutgood)

James Turrell - Baker Pool, 2002-2008

See more of James Turrell posts here.

(via astrowomyn)