How MIRI became Webb’s coolest instrument
The NASA/ESA/CSA James Webb Space Telescope is widely referred to as the successor to the NASA/ESA Hubble Space Telescope. In reality, it is the successor to a lot more than that. With the inclusion of the Mid-InfraRed Instrument (MIRI), Webb also became a successor to infrared space telescopes such as ESA’s Infrared Space Observatory (ISO) and NASA’s Spitzer Space Telescope.
At mid-infrared wavelengths, the Universe is a very different place from the one we are used to seeing with our eyes. Stretching from 3 to 30 micrometres, mid-infrared reveals celestial objects with temperatures of 30 to 700ºC. In this regime, objects that appear dark in visible light images now shine brightly.
For example, the dust clouds in which stars are forming tend to be at these temperatures. In addition, molecules tend to be easy to see at these wavelengths. “It’s such an exciting wavelength range in terms of the chemistry that you can do, and the way you can understand star formation and what’s happening in the nuclei of galaxies,” says Gillian Wright, the Principal Investigator for the European Consortium behind the MIRI instrument.
Our first real glimpses of the mid-infrared cosmos came from ISO, which was operational between November 1995 and October 1998. Arriving in orbit in 2003, Spitzer made further progress at similar wavelengths. Both ISO and Spitzer’s discoveries highlighted the need for a mid-infrared capability with a larger collecting area for better sensitivity and angular resolution to advance many big questions in astronomy.
Gillian and others began to dream of an instrument that could see the mid-infrared in vivid detail. Unfortunately for them, ESA and NASA saw the shorter wavelengths of the near infrared as the primary goal for Webb. ESA would take the lead on a near infrared spectrometer, which became NIRSpec, and NASA set its sights on an imager that became NIRCam.
Not to be deterred, when ESA issued a call for proposals to study their near infrared spectrometer instrument, Gillian and her colleagues saw a chance.
“I led a team that put in a rather cheeky response. It said we’ll study the near infrared spectrograph but we’ll also have an extra channel doing all of this mid-infrared science too. And we presented the science case for why mid infrared astronomy would be fantastic on Webb,” she says.
Although her team did not win that particular contract, the gutsy move helped raise the profile of mid-infrared astronomy in Europe, and she herself was invited to represent those science interests on another ESA study that surveyed European industry’s ability to build infrared instrumentation. Assisted by academic institutions from across Europe, part of that study looked at mid-infrared instrumentation.
The results were so encouraging, as were those of parallel US-led studies, that the appetite for such an instrument grew even larger. By pulling together in Europe an international collaboration of scientists and engineers willing and able to design and build the instrument – and crucially raise the money to do so – Gillian and her collaborators encouraged and gradually convinced ESA and NASA to include it on Webb.
Large consortia are not an unusual way to build spacecraft instruments in Europe. ESA often builds the spacecraft or telescope and then relies of consortia of academic and industrial institutions to raise funds from their national governments to build the instruments. But it is unusual in the US, where NASA usually funded the instrumentation as well.
Extending European leadership in this method of working into the realm of international collaboration with the US, on a flagship NASA mission where the culture of instrument building is so different, was not a guaranteed recipe for success.
“The biggest fear was that this complexity would be the biggest threat to the instrument,” says Jose Lorenzo Alvarez, MIRI Instrument Manager for ESA.
But the gamble paid off as Jose explains, “It was surprising to see the change in attitudes between people with entirely different working cultures. In the first years, we were on a learning curve. In the end, MIRI, which was organisationally more complex, was the first instrument to be delivered.”
In addition to raising their own money, the consortium had been given another caveat: the instrument could have no impact on the Webb’s operating temperatures and optics. In other words, the telescope would remain optimised for the near-infrared instruments, and MIRI would accept whatever it could get. This would limit the instrument’s performance beyond ten micrometres but it was a small price to pay for Gillian. “I never saw it as a compromise because it would still be better than anything we had ever seen before,” she says.
One of the biggest technological hurdles to overcome was that MIRI needed to operate at a lower temperature than the near-infrared instruments. This was achieved with the cryocooler mechanism provided by NASA’s Jet Propulsion Laboratory. To be sensitive to the mid-infrared wavelengths, MIRI operates at around 6 Kelvin (–267°C). This is lower than the average surface temperature of Pluto, which is around 40 Kelvin (–233°C). Coincidently, this temperature is where the other instruments and the telescope operate. Both are extremely cold temperatures but because of that difference, heat from the telescope would still leak into MIRI once it was harnessed to the telescope, unless the two were thermally isolated from one another.
“To minimize the thermal leaks we had to choose some quite strange and quite exotic harness materials to minimize the thermal conductance from one side to the other,” says Brian O’Sullivan, MIRI System Engineer for ESA.
Another challenge was the limited space available for the instrument on the telescope. This was made even more difficult since MIRI was to be effectively two instruments in one, an imager and a spectrometer. It called for some clever design work.
“We’ve got a mechanism, and we not only use light shining off one side, but we use the other side of it, too, just to minimise the number of mechanisms we use and the space we take up. It’s a very interesting and very compact optical design,” says Brian.
The instrument uses one light path for its imager, and another for its spectrometer.
Even after the instrument was completed and delivered to NASA for integration with the rest of the telescope, there were more challenges for the team to face.
The fiercely complicated telescope took longer to complete than anyone had imagined and that meant MIRI and the other instruments would be required to survive on the ground for much longer than originally planned. Designed to remain on Earth for about three years before launch, it took almost a decade more before the spacecraft reached orbit. To ensure the health of the instrument, MIRI was stored in a strictly controlled conditions and periodically tested.
Then on Christmas Day 2021, an ESA Ariane 5 rocket carried the spacecraft into orbit in a picture-perfect launch. In the weeks and months that followed, ground teams readied the telescope and its instruments and handed over to the scientists.
Alongside the other instruments, MIRI is now sending back the kind of data that the scientists had been dreaming about.
“Yeah, those first few months in particular were quite surreal,” says Sarah Kendrew, MIRI Instrument and Calibration Scientist, ESA. “We’d been doing so much preparatory work with simulated data, so in a sense we knew what the data would look like. So you could be looking at it thinking it all looks very familiar, but then at the same time, it’s just like, but it came from space!”
MIRI’s data featured heavily in the very first images released from Webb, including the ‘mountains’ and ‘valleys’ of the Carina nebula, the interacting galaxy group Stephan Quintet, and the Southern Ring Nebula. Subsequent images have continued to raise the bar both in terms of beauty and science.
However, because MIRI is such a large step up from any previous mid-infrared instrument, the bar is also raised in terms of being able to interpret the images. “MIRI is giving us a lot of very new things that are harder to interpret, just because MIRI is such a big difference from what there was before,” says Sarah.
But this is the essence of cutting-edge science and astronomers are already racing to develop more detailed computer models that can tell them more about the various physical processes that give raise to mid-infrared readings.
“There’s a huge potential for new understanding with MIRI, particularly in star formation and the properties of dust and galaxies. It may take a bit longer to interpret but I think the new science that will come out of MIRI is going to be really, really substantial,” says Sarah.
MIRI, together with the other instruments on Webb, has the potential to advance every branch of astronomy. It is the kind of transformative science that comes about only through a large step-up in capability. And it is a remarkable testament to the team-work and international collaboration that went into the telescope in general, and MIRI in particular.
“The thing that made MIRI happen was team spirit. We all wanted the same thing, which was the science. People’s willingness to work together and solve problems together was really what made MIRI happen,” says Gillian.
And now the whole world is benefiting.
Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona. Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).
The MIRI consortium consisted of institutions and industry from ten European countries, ESA and NASA. The leading consortium partners were: UK Astronomy Technology Centre, Airbus UK, University of Leicester, Rutherford Appleton laboratory, Cardiff University, UK; DIAS, Eire; CSL, University of Leuven, Belgium; CEA, LESIA/LAM, France; INTA, Spain; University of Stockholm, Sweden; DTUSpace, Denmark; NOVA IR Group, University of Leiden, Netherlands; MPIA Heidelberg, University of Köln, Germany; ETH, Cover, Switzerland.
These fish from Thailand glow from the inside out
Purpose of rainbow shimmer is unknown
From the darkness of a fish tank comes a blur of movement, followed by shimmering rainbow light.
That’s what it looks like when ghost catfish go for a swim.
The species appear transparent, or clear, at first, but as they move, the fish begin to glow with a rainbow light.
A new study found why: Ghost catfish reflect light from within.
That’s different from other animals that change colours as they move.
Those animals reflect light off outer surfaces like feathers and scales.
What is a ghost catfish?
Ghost catfish are a species of fish with no scales.
They measure just a few centimetres in length. That’s a bit smaller than a paperclip.
Their exposed skin is so transparent that about 90 per cent of light can pass through.
Ghost catfish are sometimes called glass catfish because of their transparent skin. (Image credit: Qibin Zhao/The Associated Press)
Though they’re native to Thailand’s rivers, ghost catfish are sold in pet stores all over the world.
How do they make rainbows?
The muscles inside ghost catfish are able to bend light.
This produces a shimmering rainbow as the fish swim.
Their muscles move as they swim, resulting in flashes of colours that look like a shimmering rainbow.
This process was discovered in a study led by physicist Qibin Zhao at the Shanghai Jiao Tong University in China.
The study was published in the Proceedings of the National Academy of Science journal on March 13.
Light passes through a ghost catfish in a fish tank, revealing a rainbow of colour. (Image credit: Xiujun Fan, Qibin Zhao/The Associated Press)
Why is this unique?
There are many iridescent animals that make a shimmer, such as beetles, hummingbirds, butterflies and other types of fish.
These species mostly reflect light off external skin, scales or feathers.
Ghost catfish are also iridescent, but they are different because they reflect light from inside their bodies.
In other animals, iridescence is often used to communicate warnings, according to biologist Ron Rutowski at Arizona State University.
But scientists still don’t know what purpose ghost catfishes’ rainbows serve.
Click play to see the ghost fish glow!
Check out these other animal news videos:
Have more questions? Want to tell us how we’re doing? Use the “send us feedback” link below. ⬇️⬇️⬇️
With files from The Associated Press
TOP IMAGE CREDIT: Qibin Zhao/Associated Press with graphic design by Philip Street/CBC
Archaeologists discover and replicate earliest musical instrument in the Middle East
Archaeologists are hearing for the first time how humans made music some 12,000 years ago, by recreating a flute that was likely used to hunt ducks and other small birds in northern Israel.
On Friday, a team of Israeli and French researchers published an article about the recreated bone flute in the peer-reviewed Nature Scientific Report, offering an auditory window into how early humans shifted from hunter-gatherers to more settled villages, creating the earliest known musical instruments ever discovered in the Middle East.
The French-Israeli team of archaeologists discovered fragments of seven different flutes, dating to around 10,000 BCE, which is the largest collection of prehistoric sound-producing instruments ever found in the Levant. The pieces were found at the Eynan/Ain Mallaha site, a small village some 35 km (20 miles) north of the Sea of Galilee. The site was inhabited from 12,000 BCE to 8,000 BCE, around the time when humans were undergoing a massive revolution from nomadic hunter-gatherers to more sedentary, semi-settled communities.
Dr. Laurent Davin, a post-doctoral fellow at Hebrew University, was examining some of the bones recovered from the site when he noticed tiny holes drilled at regular intervals along a few of the bones. At first, experts had dismissed the holes as regular wear and tear on the delicate bird bones. But Davin examined the bones more closely and noticed that the holes were at very even intervals, and clearly created by humans.
“One of the flutes was discovered complete, and so far as is known it is the only one in the world in this state of preservation,” Davin said in a press release that accompanied the article’s publication.
Dr. Hamoudi Khalaily, a senior researcher with the IAA, spent 10 years excavating at the Eynan site and was instrumental in creating a replica of the extant flute.
“There were a lot of doubts that this was even possible [to recreate], but the replica was created exactly [in the same way] as the original and it allowed us to hear what people would have heard 12,000 years ago,” Khalaily told The Times of Israel.
“When we first heard it, it gave us this feeling like, we are really doing something for history,” Khalaily said.
The recreated flute produces a screeching, breathy whistling sound that Khalaily and the team believe could be an imitation of predator birds, including falcons, which eat small waterfowl.
“The sound could have attracted predator birds, which creates chaos with the other birds, and then it’s very easy to catch them, even with your hands,” explained Khalaily.
Previously, nomadic hunter-gathers had focused on bigger game such as gazelles, rabbits, or foxes. But when humans began settling in the Hula Valley for the first time, they started taking advantage of new food sources, including fish and smaller waterfowl in the lake that used to stretch across the Hula Valley.
Today, the Hula Valley is still a major conduit for bird migration in the late fall when tens of thousands of birds pass through Israel on their way from Europe to Africa. The Hula Valley was once covered by water, with a 13 square kilometer (5 square mile) lake and 47 square kilometers (18 square miles) of seasonal swamps. Early Zionist pioneers drained the swamp in the early 20th century as a major infrastructure project to create more agricultural land and to combat malaria.
A trove of bird bones
At the Eynan site, archaeologists are excavating a small Natufian village, which was a Mesolithic culture in the Levant and Western Asia around 9000 BCE. It’s a unique time because the culture emerged when humans started living a semi-sedentary lifestyle predating the agricultural revolution, meaning they had to find regular food sources in the same area even before they knew how to cultivate them. Once humans became more settled, their culture underwent dramatic societal change including the appearance of burial practices, art, and durable structures.
The Eynan site was first excavated by a French mission in 1955 and later from 1996–2005 by a joint team from Israel and France directed by François Valla of the Centre Nationale de Recherche Scientifique (CNRS) and Khalaily of the Israel Antiquities Authority.
Excavations at the site are ongoing and it can take years to methodically sift through all of the earth removed from a site and search for fragments of tools, animal bones, or other detritus from daily life thousands of years ago. Over the past two decades, careful sifting has yielded 1,112 bird bones from the Eynan site.
The bone flute was researched and recreated by a team of French and Israeli experts, consisting of archaeologists and archaeozoologists, who study animal bones, ethnomusicologists, paleo-organologists (the research of ancient sound-making instruments), and technical experts that were able to find ways to recreate the exact placement of the finger holes.
The original flutes, also called aerophones because they are an instrument that produces sound due to vibrating air, were made from the hollow wing bones of the Eurasian teal and the Eurasian coot. The current replica was made from the wing bones of two female mallard ducks “because of the difficulty in obtaining carcasses of Eurasian coot (Fulica atra) used by the Natufians,” the article stated.
The tinier the bone, the more difficult it is to play. The researchers believe the bones were chosen specifically to mimic the calls of the Eurasian Sparrowhawk and the Common Kestrel, two birds of prey that were widespread in the Hula Valley.
The flute represents the oldest musical instrument found locally, but it is not the oldest aerophone that has been discovered. Most of the known Paleolithic sound-making instruments are found in Europe, and the oldest dates to around 40,000 years ago, which was found in southwestern Germany, made from bird bone and mammoth ivory.
Previous to this discovery, the only known “music” or sound production during the Paleolithic and Neolithic periods in the Levant was from a few studies suggesting that humans could have developed a belt of bone pendants that clacked and rattled, or possibly a bone whistle (flute with no fingerholes).
The flute represents an important discovery, but it’s not music to everyone’s ears.
“I heard it for the first time on Youtube, and it’s really a terrible tone, it’s high and pitchy and not nice at all to my ear,” said Prof. Rivka Rabinovich, the scientific director of archeozoological collections at the National Natural History Collections at the Hebrew University. Rabinovich, an expert in studying and interpreting the remains of ancient mammal bones has been studying the discoveries from the Eynan site for years.
Rabinovich added that there’s no way of knowing whether ancient humans had a similar cringe reaction when they heard it; whether it was used for hunting, communication, or making music.
But it opens a window into a fascinating point in human development, the complexity of society and their ability to make tools. The small finger holes in the flute were drilled with the talon of a larger bird, likely a falcon. Archaeologists believe that talons also had spiritual significance to early humans, Khalaily said.
“It’s very interesting because this is just at the starting point of people becoming more sedentary,” Rabinovich said. “It’s a very exciting period at which to understand the day-to-day life and also larger questions beyond day-to-day life, and why they did certain things.”
She credited the discovery to the large and varied French-Israeli team, which united researchers and archaeologists with areas of expertise in niche areas like reconstructing bone tools and interpreting scratches made in animal bones.
“The message from this is that you really need to save everything [excavated from a site] because you always see these things with new eyes and new tools,” she said. “It takes a long time to sift through things, and when you look at it anew, you can see it differently. That’s because there’s continually new research, there’s continually new technology, and new ways to investigate new information. And it all works together to create a more complete picture of what happened there.”
The Eynan site hosted continuous human presence for around 4,000 years, with people living in round houses made of stones with animal hides or branches for roofs. In 8,000 BCE, when the agricultural revolution was well underway, humans abandoned the site, moving around 500 meters closer to the Hula Lake, whose contours had changed with time.
One of the most important tests on the flute is yet to come: In late fall, when the annual bird migration through the Hula Valley takes place, Khalaily plans to take the replicated flute to the Eynan site and play it there, in the same spot where humans created it 12,000 years ago.
“I want to go and see if we can make these voices, in hopes of attracting a hawk or falcon,” he said. “I’m naturally an optimistic person, but I do really think it will work. If we were able to replicate this sound, I’m certain it will bring those birds to us.”
NASA Astronomy Picture of the Day 9 June 2023: Webb Telescope snaps Pandora Cluster – HT Tech
Most galaxies exist in groups or clusters with dozens or hundreds of members, and these cluster galaxies are all in constant motion, pulled and twisted by their neighbour’s gravity. Galaxies exist in the vastness of space, consisting of various celestial objects such as stars, clouds of dust, and gas, all of which are bound together by gravity. These galaxy clusters are the largest objects in the Universe bound by gravity and astronomers can use them to measure important cosmological properties, according to NASA.
Today’s NASA Astronomy Picture of the Day is a snapshot of Abell 2744, also known as the Pandora’s Cluster of galaxies which is located about 4 billion light-years away towards the constellation of Sculptor. This galaxy cluster formed when four smaller galaxy clusters piled up nearly 350 million years ago, according to NASA. Shockingly, the galaxies in this cluster only account for 5 percent of its mass while dark matter inside it accounts for nearly 75 percent!
Tech used to capture the picture
This awesome snapshot was captured by the NIRCam instrument aboard the James Webb Space Telescope (JWST). It is operated by NASA in collaboration with ESA and is used to capture various celestial objects in stunning detail with the help of its suite of highly advanced instruments and cameras.
It also has sophisticated instruments like the Near Infrared Camera (NIRCam) which is the primary camera onboard the telescope. It has three specialized filters and captures images in two different infrared ranges. NIRCam also has coronagraphic and spectroscopic capabilities and is the primary tool for the alignment of the telescope. The space telescope also has Mid-Infrared Instrument (MIRI) and NIRSpec instruments onboard which aid in capturing mesmerizing snapshots of objects in space.
NASA’s description of the picture
This deep field mosaicked image presents a stunning view of galaxy cluster Abell 2744 from the James Webb Space Telescope’s NIRCam. Also dubbed Pandora’s Cluster, Abell 2744 itself appears to be a ponderous merger of three different massive galaxy clusters some 3.5 billion light-years away toward the constellation Sculptor. Dominated by dark matter, the mega-cluster warps and distorts the fabric of spacetime, gravitationally lensing even more distant objects.
Redder than the Pandora cluster galaxies many of the lensed sources are very distant galaxies in the early Universe, stretched and distorted into arcs. Of course distinctive diffraction spikes mark foreground Milky Way stars. At the Pandora Cluster’s estimated distance this cosmic box spans about 6 million light-years. But don’t panic. You can explore the tantalizing region in a 2 minute video tour.
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