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Why stars look spiky in images from the James Webb Space Telescope – The Verge

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Stars in the new images from the James Webb Space Telescope look sharper than they did before. And I’m not just talking about the image quality, which is astounding. I’m talking about the fact that many of the bright stars in the images have very distinct Christmas-ornament-looking spikes or, as one of my colleagues put it, “It looks like a J.J. Abrams promo poster, and I love it.”

But this isn’t a case of too much lens flare. Those are diffraction spikes, and if you look closely, you’ll see that all bright objects in the JWST images have the same eight-pointed pattern. The brighter the light, the more prominent the feature. Dimmer objects like nebulae or galaxies don’t tend to see quite as much of this distortion.

This pattern of diffraction spikes is unique to JWST. If you compare images taken by the new telescope to images taken by its predecessor, you’ll notice that Hubble only has four diffraction spikes to JWST’s eight. (Two of JWST’s spikes can be very faint, so it sometimes appears as though there are six.)

The shape of the diffraction spikes is determined by the telescope’s hardware, so let’s start with a quick refresher of the important bits. Both Hubble and JWST are reflecting telescopes, which means that they collect light from the cosmos using mirrors. Reflecting telescopes have a large primary mirror that gathers the light and reflects it back to a smaller secondary mirror. The secondary mirror on space telescopes helps guide that light toward the science instruments that turn it into all the cool images and data we’re seeing now.

Both the primary and secondary mirrors contribute to the diffraction spikes but in slightly different ways. Light diffracts, or bends, around objects like mirror edges. So the shape of the mirror itself can result in these spikes of light as light interacts with the edges of the mirror. In Hubble’s case, the mirror was round, so it didn’t add to the spikiness. But JWST has hexagonal mirrors that result in an image with six diffraction spikes.

There’s also the secondary mirror. Secondary mirrors are smaller than primary mirrors and are held in place some distance away from the primary mirror by struts. In the case of JWST, the struts are 25 feet long. Light passing by these struts gets diffracted, resulting in more spikes, each one perpendicular to the strut itself.

In Hubble’s case, its four struts resulted in the four distinct spikes you see in Hubble pictures. JWST has three struts holding up its secondary mirror, resulting in another six spikes.

That’s a lot of distortion. To minimize the number of diffraction spikes, JWST was engineered so that four of the spikes caused by the struts would overlap with four of the spikes caused by the mirror. That leaves the eight soon-to-be-iconic diffraction spikes of a JWST image.

Some of the spikes will look more or less visible depending on which instrument is processing the light as well. This is most noticeable in the JWST images of the Southern Ring Nebula, which were released this week.

The image on the left was taken by JWST’s NIRCam, which gathers near-infrared light. The one on the right was taken by the telescope’s MIRI instrument, which picks up mid-infrared light instead. “In near-infrared light, stars have more prominent diffraction spikes because they are so bright at these wavelengths,” an explanation posted by the Space Telescope Science Institute says. “In mid-infrared light, diffraction spikes also appear around stars, but they are fainter and smaller (zoom in to spot them).”

If you want a visual of how diffraction spikes on JWST work, check out the handy infographic below from NASA and the Space Telescope Science Institute:

This is a diagram labeled “Webb’s Diffraction Spikes”. The top right of the image shows three stars producing eight-pronged diffraction spike patterns. This diagram is composed of five sections.


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Remains of small armor-plated dinosaur found in Argentina – Mint Lounge

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Buenos Aires, Reuters: Paleontologists on Thursday heralded the discovery of a previously unknown small armored dinosaur in southern Argentina, a creature that likely walked upright on its back legs roaming a then-steamy landscape about 100 million years ago.

The Cretaceous Period dinosaur, named Jakapil kaniukura, would have been well-protected with rows of bony disk-shaped armor along its neck and back and down to its tail, they said. It measured about 5 feet (1.5 meters) long and weighed only 9 to 15 pounds (4-7 kg), similar to an average house cat.

Also read: New dinosaur found in Mexico was ‘very communicative’

Its fossilized remains were dug up over the past decade near a dam in Patagonia in Rio Negro province’s La Buitrera paleontological zone. The scientists described Jakapil in a study published in the journal Scientific Reports (https://www.nature.com/articles/s41598-022-15535-6.pdf.)

The scientists said Jakapil marks a first-of-its-kind discovery of an armored dinosaur from the Cretaceous in South America. It is part of the thyreophoran dinosaur group that includes the likes of Stegosaurus, known for its bony back plates and spiky tail, and tank-like Ankylosaurus, covered in armor and wielding a club-like tail.

Also read: Fish once labeled a living fossil surprises scientists again

Lead paleontologist Sebastian Apesteguia and his colleagues found a partial skeleton of Jakapil along with 15 tooth fragments featuring a leaf-like shape, similar to iguana teeth.

Jakapil resembles a primitive form of thyreophoran that lived much earlier, making it a surprise that it dated from the Cretaceous. Apesteguia said never before has such a thyreophoran been dug up anywhere in the southern hemisphere. 

(Reporting by Miguel Lo Bianco; Writing by David Alire Garcia; Editing by Will Dunham for Reuters)

Also read: ‘Death shadow’ dinosaur is largest megaraptor ever unearthed

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Perseid meteor shower of 2022 thrills stargazers despite bright moon (photos) – Space.com

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The Perseid meteor shower of the 2022 reached its peak this weekend and while the bright full moon may have washed out the best of the “shooting stars” display this year, that doesn’t mean skywatchers were left completely in the dark.

Stargazers around the world captured some dazzling views of the Perseid meteor shower as it peaked overnight Friday and Saturday (Aug. 12-13) and they shared the photos to prove it. Some observers took to Twitter to share their meteor views while other astrophotographers snapped truly stunning photos for Getty Images. 

“Perseid fireball I saw last night from Oxfordshire,”  skywatcher Mary McIntyre of Oxfordhire in the United Kingdom wrote (opens in new tab) on Twitter, adding that she captured the Perseid photos with a meteor camera. “The ionization trail was awesome.”

Related: Perseid meteor shower generates early “shooting stars” (video)

The Perseid meteor shower is typically one of the best meteor displays of the year, but its peak in 2022 came just one day after the Sturgeon supermoon (August’s full moon) on Aug. 11. Since dark skies are vital for meteor watching, even bright moonlight can dim a stargazers prospects. 

Photographer Wu Zhengjie for the photo service VCG and Getty Images still managed to capture stunning views of the Perseids from the Eboliang Yardang landform in Haixi Mongolian and Tibetan Autonomous Prefecture, Qinghai Province of China. The images show brilliant Perseid meteors over a striking landscape. 

Another photographer, Veysel Altun of the Anadalou Agency and Getty Images, managed to capture a Perseid meteor streak over a campsite in Samsun, Turkey. 

A Perseid meteor streaks across the night sky over Atakum district of Samsun, Turkey on Aug. 13, 2022.  (Image credit: Veysel Altun/Anadolu Agency via Getty Images)

Photographer Ercin Ertuk, also of the Anadalou Agency and Getty Images, snapped a photo of a Perseid as it streaked across the sky over trees in Ankara, Turkey.

A view of the Perseid meteor shower over Ankara, Turkey on August 13, 2022. (Image credit: Ercin Erturk/Anadolu Agency via Getty Images)

Still more stargazers managed to catch views of the Perseids with either their own cameras or meteor cameras that constantly watch the sky to record fireballs. Here’s a look at some of our favorites spotted on Twitter.

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The Perseid meteor shower occurs each year in mid-August when the Earth passes through the dusty trail of the Comet Swift-Tuttle. When those comet bits slam into Earth’s atmosphere, they can spawn bright trails as the streak across the sky. They appear to radiate out from the constellation Perseus, hence their name. 

The next major meteor shower of 2022 will be the Orionid meteor shower in October. That shower will peak on Oct. 20 and 21, but its activity period runs from Sept. 26 to Nov. 22. It is caused by the remnants of Halley’s Comet as the Earth passes through that trail. 

Check out our guide for the best meteor showers of the year to prepare for your next stargazing experience.

Editor’s note: If you snap an amazing photo of a Perseid meteor or any other night-sky sight and you’d like to share it with Space.com for a story or image gallery, send images, comments and location information to spacephotos@space.com.

Email Tariq Malik at tmalik@space.com (opens in new tab) or follow him @tariqjmalik (opens in new tab). Follow us @Spacedotcom (opens in new tab)Facebook (opens in new tab) and Instagram (opens in new tab).

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B.C. poet illuminates pages of popular scientific magazine with verses about the nature of light – CBC.ca

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On clear summer nights, poet Donna Kane sleeps on the front deck of her farmhouse in Rolla, B.C., in an old-fashioned bed under a blue quilt printed with crescent moons.

The writer draws inspiration from looking at the sky in this northern part of the province, more than 750 kilometres distant from Vancouver.

“I feel connected. I feel like I’m part of something bigger than myself, and I feel comforted by that. You’re looking at the origins of light when you’re lying there, looking up at the stars,” Kane said.

Kane’s musings about star light in the night sky inspired her to write a poem that blends scientific principles and the human experience of light’s reflection — a poem that now appears in a respected U.S. science magazine.

The poem, On Visible Light, was published in the July edition of Scientific American magazine, alongside more traditional scholarly research on the thermodynamic limit, momentum computing and interstellar space.

For Kane, the inclusion of her poem is proof that literature and science are more closely connected than many people believe.

“I’ve always thought science and art are very, very similar, trying to discover the mysteries of the world and the universe. They both have that urge,” Kane told CBC News. 

“Poetry explores. Ideas can emerge from really good poems that maybe scientists hadn’t really thought of in that same way.” 

‘Science and art are very, very similar because both disciplines are trying to explore the mysteries of the world and the universe,’ poet Donna Kane said. (Submitted/Donna Kane)

Kane’s poem is a villanelle, a structured type of poem with refrains and a strict rhyming pattern, a form that dates back hundreds of years. She weaves together science and imagery with lines like “Just a slice of electromagnetic/ wavelength and sight is ours, a blindness gone/ at the end of travelling through our nights.”

Its appearance in the pages of Scientific American, which has more than eight million online readers worldwide each month, has brought Kane stratospheric exposure.

“I’m pretty sure I’m never going to get a bigger audience than that,” said Kane. “Usually the reach of poetry is very small.”

The cover of 'Scientific American', whose lead story is 'Voyagers' Final Frontier'. It features an image of a satellite.
Kane’s poem features in the July issue of Scientific American. The magazine has an online readership of around eight million each month. (Submitted/Scientific American)

The editor of Scientific American’s poetry column, Dava Sobel, told CBC News that Kane’s poem is “gorgeous.” 

“It’s emotionally evocative and yet scientifically informative. And it adheres to a very strict poetic form. So it’s a difficult thing to achieve. But she’s really done it,” said Sobel, a former science writer for the New York Times who was a finalist for the Pulitzer Prize.

Sobel, who had astronaut Neil Armstrong write the forward to one of her books and also has an asteroid named after her, believes that poetry can illuminate science. 

“Creativity flows smoothly between those two,” she said.

Dava Sobel poses for the camera in front of a sundial. She has white hair, cut short, and is wearing red-rimmed glasses.
Dava Sobel, poetry editor of Scientific American, has previously published poetry written by Nobel Prize winners in chemistry and physics. (Submitted/Glen Allsop)

Sobel said Scientific American published poetry in its very first issue in 1845 but only featured rarely since, until she launched a monthly science poetry column in the magazine in 2020.

Since then, in addition to Kane’s villanelle, she’s included poems written by Nobel Prize winners in chemistry and physics.

“Poetry should not be off limits to anybody, nor should science,” she said.

Even though it’s an imaginative work, Kane’s poem still had to meet the bar for accuracy and was rigorously fact checked by Scientific American before it was published.

“They’re pretty serious that … what you’ve written is accurate. You can do playful things, but the poem has to stand up to the actual science,” said Kane.

B.C. poet Donna Kane's face is shown reflected in the Pioneer 10 space craft during a visit to the Smithsonian Museum in Washington, D.C.
Donna Kane’s face is reflected in a prototype of the Pioneer 10 space craft during a visit to the Smithsonian Museum in Washington, D.C. The B.C. poet is drawn to writing about science and space. (Submitted/Donna Kane)

The poet said she’s always loved science and has written other works about space.

Her 2020 book, Orrery: Poems, featured a number of pieces about Pioneer 10, a space probe launched to study Jupiter’s moons. It was a finalist for a Governor General’s Award for English-language poetry. 

One of her space-themed poems will be included in a forthcoming anthology published by Cambridge University Press.

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