Toocool - Blog Posts
The Beauty of Webb Telescope’s Mirrors
The James Webb Space Telescope’s gold-plated, beryllium mirrors are beautiful feats of engineering. From the 18 hexagonal primary mirror segments, to the perfectly circular secondary mirror, and even the slightly trapezoidal tertiary mirror and the intricate fine-steering mirror, each reflector went through a rigorous refinement process before it was ready to mount on the telescope. This flawless formation process was critical for Webb, which will use the mirrors to peer far back in time to capture the light from the first stars and galaxies.
The James Webb Space Telescope, or Webb, is our upcoming infrared space observatory, which will launch in 2019. It will spy the first luminous objects that formed in the universe and shed light on how galaxies evolve, how stars and planetary systems are born, and how life could form on other planets.
A polish and shine that would make your car jealous
All of the Webb telescope’s mirrors were polished to accuracies of approximately one millionth of an inch. The beryllium mirrors were polished at room temperature with slight imperfections, so as they change shape ever so slightly while cooling to their operating temperatures in space, they achieve their perfect shape for operations.
The Midas touch
Engineers used a process called vacuum vapor deposition to coat Webb’s mirrors with an ultra-thin layer of gold. Each mirror only required about 3 grams (about 0.11 ounces) of gold. It only took about a golf ball-sized amount of gold to paint the entire main mirror!
Before the deposition process began, engineers had to be absolutely sure the mirror surfaces were free from contaminants.
The engineers thoroughly wiped down each mirror, then checked it in low light conditions to ensure there was no residue on the surface.
Inside the vacuum deposition chamber, the tiny amount of gold is turned into a vapor and deposited to cover the entire surface of each mirror.
Primary, secondary, and tertiary mirrors, oh my!
Each of Webb’s primary mirror segments is hexagonally shaped. The entire 6.5-meter (21.3-foot) primary mirror is slightly curved (concave), so each approximately 1.3-meter (4.3-foot) piece has a slight curve to it.
Those curves repeat themselves among the segments, so there are only three different shapes — 6 of each type. In the image below, those different shapes are labeled as A, B, and C.
Webb’s perfectly circular secondary mirror captures light from the 18 primary mirror segments and relays those images to the telescope’s tertiary mirror.
The secondary mirror is convex, so the reflective surface bulges toward a light source. It looks much like a curved mirror that you see on the wall near the exit of a parking garage that lets motorists see around a corner.
Webb’s trapezoidal tertiary mirror captures light from the secondary mirror and relays it to the fine-steering mirror and science instruments. The tertiary mirror sits at the center of the telescope’s primary mirror. The tertiary mirror is the only fixed mirror in the system — all of the other mirrors align to it.
All of the mirrors working together will provide Webb with the most advanced infrared vision of any space observatory we’ve ever launched!
Who is the fairest of them all?
The beauty of Webb’s primary mirror was apparent as it rotated past a cleanroom observation window at our Goddard Space Flight Center in Greenbelt, Maryland. If you look closely in the reflection, you will see none other than James Webb Space Telescope senior project scientist and Nobel Laureate John Mather!
Learn more about the James Webb Space Telescope HERE, or follow the mission on Facebook, Twitter and Instagram.
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Behind a TED-Ed Lesson: Animation + Inspiration
To celebrate George Seurat’s birthday today, we thought we’d do a deep dive behind the scenes of one of our animated lessons, How do schools of fish swim in harmony?, which is about the concept of ‘emergence’ and whose animated style just so happens to have been largely influenced by the paintings of George Seurat and his contemporaries.
Emergence refers to the spontaneous creation of sophisticated behaviors and functions from large groups of simple elements, and can be used to explain the movements of ants, fish, and birds, as well as how the tiny cells in your brain give rise to the complex thoughts, memories, and consciousness that are you.
A Sunday Afternoon on the Island of La Grande Jatte, George Seurat (1884–86)
It’s kind of like a pointillist painting. When you zoom in real close, it’s just a collection of chaotic brush strokes. But take a few steps back, and you’ll see that all of those brush strokes are working together to illustrate a complex and detailed scene.
Pointillism stems from Impressionism, and depending on the artist’s technique, the size of the brush strokes vary, but are always visible. For example, Vincent van Gogh’s The Starry Night uses larger brush strokes in the night sky. Both the above and below concept designs show the animator of this lesson testing out how different brushstrokes interact to create depth within a scene. She decided that the swirling waters would make sense as large brushstrokes, which also offered contrast to allow the small fish to stand out.
George Seurat also employed a technique called ‘divisionism’, sometimes known as ‘chromoluminarism’, in which colors were separated into individual dots or patches which interacted optically. So, rather than relying on mixing colors, painters like Seurat and Paul Signac juxtaposed contrasting colors to allow for optical mixing - which in theory would produce more vibrant and pure colors than the traditional process of mixing pigments.
Circus Sideshow (Parade de Cirque), George Seurat (1887–88)
While designing this TED-Ed lesson, George Seurat and Paul Signac’s paintings provided inspiration not just for the brushstroke technique, but also for the color palette.
This GIF of the brain and it’s neural connections draws many of its colors from Seurat’s circus series palette, while the brighter colors - such as the ones used in the title GIF above - are drawn from the more vibrant colors commonly used by Paul Signac, like in the painting below.
Notre-Dame-de-la-Garde (La Bonne-Mère), Marseilles, Paul Signac (1905-06)
Animating this lesson was an opportunity to renew a sense of wonder in our ever complex universe, whether studying it up close or from afar. We hope that watching it might do the same for you!
From the TED-Ed Lesson How do schools of fish swim in harmony? - Nathan S. Jacobs
Animation by TED-Ed // Lisa LaBracio
Self-assembling nanoparticle arrays can switch between a mirror and a window
By finely tuning the distance between nanoparticles in a single layer, researchers have made a filter that can change between a mirror and a window.
The development could help scientists create special materials whose optical properties can be changed in real time. These materials could then be used for applications from tuneable optical filters to miniature chemical sensors.
Creating a ‘tuneable’ material - one which can be accurately controlled - has been a challenge because of the tiny scales involved. In order to tune the optical properties of a single layer of nanoparticles - which are only tens of nanometres in size each - the space between them needs to be set precisely and uniformly.
To form the layer, the team of researchers from Imperial College London created conditions for gold nanoparticles to localise at the interface between two liquids that do not mix. By applying a small voltage across the interface, the team have been able to demonstrate a tuneable nanoparticle layer that can be dense or sparse, allowing for switching between a reflective mirror and a transparent surface. The research is published today in Nature Materials.
Read more.
Voyager: The Spacecraft
The twin Voyager 1 and 2 spacecraft are exploring where nothing from Earth has flown before. Continuing their more-than-40-year journey since their 1977 launches, they each are much farther away from Earth and the Sun than Pluto.
The primary mission was the exploration of Jupiter and Saturn. After making a string of discoveries there – such as active volcanoes on Jupiter’s moon Io and intricacies of Saturn’s rings – the mission was extended.
Voyager 2 went on to explore Uranus and Neptune, and is still the only spacecraft to have visited those outer planets. The adventurers’ current mission, the Voyager Interstellar Mission (VIM), will explore the outermost edge of the Sun’s domain. And beyond.
Spacecraft Instruments
‘BUS’ Housing Electronics
The basic structure of the spacecraft is called the “bus,” which carries the various engineering subsystems and scientific instruments. It is like a large ten-sided box. Each of the ten sides of the bus contains a compartment (a bay) that houses various electronic assemblies.
Cosmic Ray Subsystem (CRS)
The Cosmic Ray Subsystem (CRS) looks only for very energetic particles in plasma, and has the highest sensitivity of the three particle detectors on the spacecraft. Very energetic particles can often be found in the intense radiation fields surrounding some planets (like Jupiter). Particles with the highest-known energies come from other stars. The CRS looks for both.
High-Gain Antenna (HGA)
The High-Gain Antenna (HGA) transmits data to Earth on two frequency channels (the downlink). One at about 8.4 gigahertz, is the X-band channel and contains science and engineering data. For comparison, the FM radio band is centered around 100 megahertz.
Imaging Science Subsystem (ISS)
The Imaging Science Subsystem (ISS) is a modified version of the slow scan vidicon camera designed that were used in the earlier Mariner flights. The ISS consists of two television-type cameras, each with eight filters in a commandable Filter Wheel mounted in front of the vidicons. One has a low resolution 200 mm wide-angle lens, while the other uses a higher resolution 1500 mm narrow-angle lens.
Infrared Interferometer Spectrometer and Radiometer (IRIS)
The Infrared Interferometer Spectrometer and Radiometer (IRIS) actually acts as three separate instruments. First, it is a very sophisticated thermometer. It can determine the distribution of heat energy a body is emitting, allowing scientists to determine the temperature of that body or substance.
Second, the IRIS is a device that can determine when certain types of elements or compounds are present in an atmosphere or on a surface.
Third, it uses a separate radiometer to measure the total amount of sunlight reflected by a body at ultraviolet, visible and infrared frequencies.
Low-Energy Charged Particles (LECP)
The Low-Energy Charged Particles (LECP) looks for particles of higher energy than the Plasma Science instrument, and it overlaps with the Cosmic Ray Subsystem (CRS). It has the broadest energy range of the three sets of particle sensors.
The LECP can be imagined as a piece of wood, with the particles of interest playing the role of the bullets. The faster a bullet moves, the deeper it will penetrate the wood. Thus, the depth of penetration measures the speed of the particles. The number of “bullet holes” over time indicates how many particles there are in various places in the solar wind, and at the various outer planets. The orientation of the wood indicates the direction from which the particles came.
Magnetometer (MAG)
Although the Magnetometer (MAG) can detect some of the effects of the solar wind on the outer planets and moons, its primary job is to measure changes in the Sun’s magnetic field with distance and time, to determine if each of the outer planets has a magnetic field, and how the moons and rings of the outer planets interact with those magnetic fields.
Optical Calibration Target The target plate is a flat rectangle of known color and brightness, fixed to the spacecraft so the instruments on the movable scan platform (cameras, infrared instrument, etc.) can point to a predictable target for calibration purposes.
Photopolarimeter Subsystem (PPS)
The Photopolarimeter Subsystem (PPS) uses a 0.2 m telescope fitted with filters and polarization analyzers. The experiment is designed to determine the physical properties of particulate matter in the atmospheres of Jupiter, Saturn and the rings of Saturn by measuring the intensity and linear polarization of scattered sunlight at eight wavelengths.
The experiment also provided information on the texture and probable composition of the surfaces of the satellites of Jupiter and Saturn.
Planetary Radio Astronomy (PRA) and Plasma Wave Subsystem (PWS)
Two separate experiments, The Plasma Wave Subsystem and the Planetary Radio Astronomy experiment, share the two long antennas which stretch at right-angles to one another, forming a “V”.
Plasma Science (PLS)
The Plasma Science (PLS) instrument looks for the lowest-energy particles in plasma. It also has the ability to look for particles moving at particular speeds and, to a limited extent, to determine the direction from which they come.
The Plasma Subsystem studies the properties of very hot ionized gases that exist in interplanetary regions. One plasma detector points in the direction of the Earth and the other points at a right angle to the first.
Radioisotope Thermoelectric Generators (RTG)
Three RTG units, electrically parallel-connected, are the central power sources for the mission module. The RTGs are mounted in tandem (end-to-end) on a deployable boom. The heat source radioisotopic fuel is Plutonium-238 in the form of the oxide Pu02. In the isotopic decay process, alpha particles are released which bombard the inner surface of the container. The energy released is converted to heat and is the source of heat to the thermoelectric converter.
Ultraviolet Spectrometer (UVS)
The Ultraviolet Spectrometer (UVS) is a very specialized type of light meter that is sensitive to ultraviolet light. It determines when certain atoms or ions are present, or when certain physical processes are going on.
The instrument looks for specific colors of ultraviolet light that certain elements and compounds are known to emit.
Learn more about the Voyager 1 and 2 spacecraft HERE.
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Scientists report the first scientific results from NASA’s Juno mission, now in orbit around Jupiter.
This week, a suite of 46 separate scientific papers describe different aspects of the giant planet Jupiter, from its massive polar cyclones, to its complex magnetic field, to its unique radiation environment. The papers mark the first full scientific results from NASA’s Juno mission, which arrived in orbit around Jupiter last summer. Later this July, the craft is slated to overfly the planet’s Great Red Spot, bringing back still more data. Juno program scientist Jared Espley and Juno radiation monitoring investigation lead Heidi Becker join Ira to sum up some of the Jovian surprises, as well as give a preview of what still lies ahead for the Juno mission. Listen here to learn more.
[Photos by NASA/JPL/MSSS/Gerald Eichstädt/Justin Cowart/Alexis Tranchandon/Solaris]
Good vibrations no longer needed for speakers as research encourages graphene to talk
A pioneering new technique that encourages the wonder material graphene to “talk” could revolutionise the global audio and telecommunications industries.
Researchers from the University of Exeter have devised a ground-breaking method to use graphene to generate complex and controllable sound signals. In essence, it combines speaker, amplifier and graphic equaliser into a chip the size of a thumbnail.
Traditional speakers mechanically vibrate to produce sound, with a moving coil or membrane pushing the air around it back and forth. It is a bulky technology that has hardly changed in more than a century.
This innovative new technique involves no moving parts. A layer of the atomically thin material graphene is rapidly heated and cooled by an alternating electric current, and transfer of this thermal variation to the air causes it to expand and contract, thereby generating sound waves.
Read more.
Shortly after he finished filming on the opulent set of Baz Luhrmann’s ‘The Great Gatsby,’ Joel headed off to the Jordanian desert to begin training for 'Zero Dark Thirty.' With a heavy dose of mock horror, he said that it was quite a shock to his delicate system:
“An experience like ‘Gatsby’ really spoils you because you are treated like a king. You’re given a big trailer, someone brings fresh flowers to your trailer, there are dates and walnuts and coconut water in your fridge … really living large.“
Then, when he suddenly found himself roughing it in the torrid desert, “sharing a cubicle with five other guys, half of them military, and carrying 50-60 kilos of equipment … It was like, 'Baz! Come and save me!’ You get a reality check."
