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Why Webb Needs to Chill

Our massive James Webb Space Telescope is currently being tested to make sure it can work perfectly at incredibly cold temperatures when it’s in deep space. 

How cold is it getting and why? Here’s the whole scoop…

Webb is a giant infrared space telescope that we are currently building. It was designed to see things that other telescopes, even the amazing Hubble Space Telescope, can’t see.  

Webb’s giant 6.5-meter diameter primary mirror is part of what gives it superior vision, and it’s coated in gold to optimize it for seeing infrared light.  

Why do we want to see infrared light?

Lots of stuff in space emits infrared light, so being able to observe it gives us another tool for understanding the universe. For example, sometimes dust obscures the light from objects we want to study – but if we can see the heat they are emitting, we can still “see” the objects to study them.

It’s like if you were to stick your arm inside a garbage bag. You might not be able to see your arm with your eyes – but if you had an infrared camera, it could see the heat of your arm right through the cooler plastic bag.

Credit: NASA/IPAC

With a powerful infrared space telescope, we can see stars and planets forming inside clouds of dust and gas.

We can also see the very first stars and galaxies that formed in the early universe. These objects are so far away that…well, we haven’t actually been able to see them yet. Also, their light has been shifted from visible light to infrared because the universe is expanding, and as the distances between the galaxies stretch, the light from them also stretches towards redder wavelengths. 

We call this phenomena  “redshift.”  This means that for us, these objects can be quite dim at visible wavelengths, but bright at infrared ones. With a powerful enough infrared telescope, we can see these never-before-seen objects.

We can also study the atmospheres of planets orbiting other stars. Many of the elements and molecules we want to study in planetary atmospheres have characteristic signatures in the infrared.

Because infrared light comes from objects that are warm, in order to detect the super faint heat signals of things that are really, really far away, the telescope itself has to be very cold. How cold does the telescope have to be? Webb’s operating temperature is under 50K (or -370F/-223 C). As a comparison, water freezes at 273K (or 32 F/0 C).

How do we keep the telescope that cold? 

Because there is no atmosphere in space, as long as you can keep something out of the Sun, it will get very cold. So Webb, as a whole, doesn’t need freezers or coolers - instead it has a giant sunshield that keeps it in the shade. (We do have one instrument on Webb that does have a cryocooler because it needs to operate at 7K.)

Also, we have to be careful that no nearby bright things can shine into the telescope – Webb is so sensitive to faint infrared light, that bright light could essentially blind it. The sunshield is able to protect the telescope from the light and heat of the Earth and Moon, as well as the Sun.  

Out at what we call the Second Lagrange point, where the telescope will orbit the Sun in line with the Earth, the sunshield is able to always block the light from bright objects like the Earth, Sun and Moon.

How do we make sure it all works in space? 

By lots of testing on the ground before we launch it. Every piece of the telescope was designed to work at the cold temperatures it will operate at in space and was tested in simulated space conditions. The mirrors were tested at cryogenic temperatures after every phase of their manufacturing process.

The instruments went through multiple cryogenic tests at our Goddard Space Flight Center in Maryland.

Once the telescope (instruments and optics) was assembled, it even underwent a full end-to-end test in our Johnson Space Center’s giant cryogenic chamber, to ensure the whole system will work perfectly in space.  

What’s next for Webb? 

It will move to Northrop Grumman where it will be mated to the sunshield, as well as the spacecraft bus, which provides support functions like electrical power, attitude control, thermal control, communications, data handling and propulsion to the spacecraft.

Learn more about the James Webb Space Telescope HERE, or follow the mission on Facebook, Twitter and Instagram.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Why can we find geometric shapes in the night sky? How can we know that at least two people in London have exactly the same number of hairs on their head? And why can patterns be found in just about any text — even Vanilla Ice lyrics? Is there a deeper meaning? 

The answer is no, and we know that thanks to a mathematical principle called Ramsey theory. So what is Ramsey theory? Simply put, it states that given enough elements in a set or structure, some particular interesting pattern among them is guaranteed to emerge.

The mathematician T.S. Motzkin once remarked that, “while disorder is more probable in general, complete disorder is impossible.” The sheer size of the Universe guarantees that some of its random elements will fall into specific arrangements, and because we evolved to notice patterns and pick out signals among the noise, we are often tempted to find intentional meaning where there may not be any. So while we may be awed by hidden messages in everything from books, to pieces of toast, to the night sky, their real origin is usually our own minds.

From the TED-Ed Lesson The origin of countless conspiracy theories - PatrickJMT

Animation by Aaron, Sean & Mathias Studios

Lava flows like these Hawaii’an ones are endlessly mesmerizing. This type of flow is gravity-driven; rather than being pushed by explosive pressure, the lava flows under its own weight and that of the lava upstream. In fact, fluid dynamicists refer to this kind of flow as a gravity current, a term also applied to avalanches, turbidity currents, and cold drafts that sneak under your door in the wintertime. How quickly these viscous flows spread depends on factors like the density and viscosity of the lava and on the volume of lava being released at the vent. As the lava cools, its viscosity increases rapidly, and an outer crust can solidify while molten lava continues to flow beneath. Be sure to check out the full video below for even more gorgeous views of lava.  (Image/video credit: J. Tarsen, source; via J. Hertzberg)

The Myth of Prometheus

Before the creation of humanity, the Greek gods won a great battle against a race of giants called the Titans. Most Titans were destroyed or driven to the eternal hell of Tartarus. But the Titan Prometheus, whose name means foresight, persuaded his brother Epimetheus to fight with him on the side of the gods. 

As thanks, Zeus entrusted the brothers with the task of creating all living things. Epimetheus was to distribute the gifts of the gods among the creatures. To some, he gave flight; to others, the ability to move through water or race through grass. He gave the beasts glittering scales, soft fur, and sharp claws.

Meanwhile, Prometheus shaped the first humans out of mud. He formed them in the image of the gods, but Zeus decreed they were too remain mortal and worship the inhabitants of Mount Olympus from below. Zeus deemed humans subservient creatures vulnerable to the elements and dependent on the gods for protection. However, Prometheus envisioned his crude creations with a greater purpose. So when Zeus asked him to decide how sacrifices would be made, the wily Prometheus planned a trick that would give humans some advantage. He killed a bull and divided it into two parts to present to Zeus. On one side, he concealed the succulent flesh and skin under the unappealing belly of the animal. On the other, he hid the bones under a thick layer of fat. When Zeus chose the seemingly best portion for himself, he was outraged at Prometheus’s deception. 

Fuming, Zeus forbade the use of fire on Earth, whether to cook meat or for any other purpose. But Prometheus refused to see his creations denied this resource. And so, he scaled Mount Olympus to steal fire from the workshop of Hephaestus and Athena. He hid the flames in a hollow fennel stalk and brought it safely down to the people. This gave them the power to harness nature for their own benefit and ultimately dominate the natural order. 

With fire, humans could care for themselves with food and warmth. But they could also forge weapons and wage war. Prometheus’s flames acted as a catalyst for the rapid progression of civilization. When Zeus looked down at this scene, he realized what had happened. Prometheus had once again wounded his pride and subverted his authority. 

Furious, Zeus imposed a brutal punishment. Prometheus was to be chained to a cliff for eternity. Each day, he would be visited by a vulture who would tear out his liver and each night his liver would grow back to be attacked again in the morning. Although Prometheus remained in perpetual agony, he never expressed regret at his act of rebellion. His resilience in the face of oppression made him a beloved figure in mythology. He was also celebrated for his mischievous and inquisitive spirit, and for the knowledge, progress, and power he brought to human hands. 

He’s also a recurring figure in art and literature. In Percy Bysshe Shelley’s lyrical drama “Prometheus Unbound,” the author imagines Prometheus as a romantic hero who escapes and continues to spread empathy and knowledge. Of his protagonist, Shelley wrote, “Prometheus is the type of the highest perfection of moral and intellectual nature, impelled by the purest and the truest motives to the best and noblest ends.” His wife Mary envisaged Prometheus as a more cautionary figure and subtitled her novel “Frankenstein: The Modern Prometheus.” This suggests the damage of corrupting the natural order and remains relevant to the ethical questions surrounding science and technology today. As hero, rebel, or trickster, Prometheus remains a symbol of our capacity to capture the powers of nature, and ultimately, he reminds us of the potential of individual acts to ignite the world.

From the TED-Ed Lesson The myth of Prometheus - Iseult Gillespie

Animation by Léa Krawczyk ( @lea–krawczyk )

How to Make a Motor Neuron

A team of scientists has uncovered details of the cellular mechanisms that control the direct programming of stem cells into motor neurons. The scientists analyzed changes that occur in the cells over the course of the reprogramming process. They discovered a dynamic, multi-step process in which multiple independent changes eventually converge to change the stem cells into motor neurons.

“There is a lot of interest in generating motor neurons to study basic developmental processes as well as human diseases like ALS and spinal muscular atrophy,” said Shaun Mahony, assistant professor of biochemistry and molecular biology at Penn State and one of the lead authors of the paper. “By detailing the mechanisms underlying the direct programing of motor neurons from stem cells, our study not only informs the study of motor neuron development and its associated diseases, but also informs our understanding of the direct programming process and may help with the development of techniques to generate other cell types.”

The direct programming technique could eventually be used to regenerate missing or damaged cells by converting other cell types into the missing one. The research findings, which appear online in the journal Cell Stem Cell on December 8, 2016, show the challenges facing current cell-replacement technology, but they also outline a potential pathway to the creation of more viable methods.

“Despite having a great therapeutic potential, direct programming is generally inefficient and doesn’t fully take into account molecular complexity,” said Esteban Mazzoni, an assistant professor in New York University’s Department of Biology and one of the lead authors of the study. “However, our findings point to possible new avenues for enhanced gene-therapy methods.”

The researchers had shown previously that they can transform mouse embryonic stem cells into motor neurons by expressing three transcription factors – genes that control the expression of other genes – in the stem cells. The transformation takes about two days. In order to better understand the cellular and genetic mechanisms responsible for the transformation, the researchers analyzed how the transcription factors bound to the genome, changes in gene expression, and modifications to chromatin at 6-hour intervals during the transformation.

“We have a very efficient system in which we can transform stem cells into motor neurons with something like a 90 to 95 percent success rate by adding the cocktail of transcription factors,” said Mahony. “Because of that efficiency, we were able to use our system to tease out the details of what actually happens in the cell during this transformation.”

“A cell in an embryo develops by passing through several intermediate stages,” noted Uwe Ohler, senior researcher at the Max Delbrück Center for Molecular Medicine (MDC) in Berlin and one of the lead authors of the work. “But in direct programming we don’t have that: we replace the gene transcription network of the cell with a completely new one at once, without the progression through intermediate stages. We asked, what are the timing and kinetics of chromatin changes and transcription events that directly lead to the final cell fate?“

The research team found surprising complexity – programming of these stem cells into neurons is the result of two independent transcriptional processes that eventually converge. Early on in the process, two of the transcription factors – Isl1 and Lhx3 – work in tandem, binding to the genome and beginning a cascade of events including changes to chromatin structure and gene expression in the cells. The third transcription factor, Ngn2, acts independently making additional changes to gene expression. Later in the transformation process, Isl1 and Lhx3 rely on changes in the cell initiated by Ngn2 to help complete the transformation. In order for direct programming to successfully achieve cellular conversion, it must coordinate the activity of the two processes.

“Many have found direct programming to be a potentially attractive method as it can be performed either in vitro – outside of a living organism – or in vivo – inside the body and, importantly, at the site of cellular damage,” said Mazzoni. “However, questions remain about its viability to repair cells – especially given the complex nature of the biological process. Looking ahead, we think it’s reasonable to use this newly gained knowledge to, for instance, manipulate cells in the spinal cord to replace the neurons required for voluntary movement that are destroyed by afflictions such as ALS.”

Cathedrals Beach, Galicia

Warrior of the grassland - Anup Deodhar - The Comedy Wildlife.