Savage 10 metre fish of the Silurian and Devonian Heavily armoured piscine torpedoes with fierce teeth roamed the oceans in the early days of fishes, in fact the Devonian era is called the age of fishes by palaeontologists as they had a huge burst of speciation and diversified to fill most marine ecological niches during this time. The now extinct (fortunately) class known as placodermi (plate skin in Greek) was the apex predator of these long gone waters, and thrived from 438 to 358 million years ago, dying out at the end Devonian mass extinction (one of the lesser ones).
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I love the fact that a group of crows is called a "Murder" and a group of ravens is a "Conspiracy"
“The stars, like dust, encircle me In living mists of light; And all of space I seem to see In one vast burst of sight.”
—
Isaac Asimov
They say a picture is worth a thousand words, but no images have left a greater impact on our understanding of the universe quite like the Hubble Space Telescope’s deep fields. Like time machines, these iconic images transport humanity billions of light-years back in time, offering a glimpse into the early universe and insight into galaxy evolution!
You’ve probably seen these images before, but what exactly do we see within them? Deep field images are basically core samples of our universe. By peering into a small portion of the night sky, we embark on a journey through space and time as thousands of galaxies appear before our very eyes.
So, how can a telescope the size of a school bus orbiting 340 miles above Earth uncover these mind-boggling galactic masterpieces? We’re here to break it down. Here’s Hubble’s step-by-step guide to viewing deep fields:
Believe it or not, capturing the light of a thousand galaxies actually begins in the dark. To observe extremely faint galaxies in the farthest corners of the cosmos, we need minimal light interference from nearby stars and other celestial objects. The key is to point Hubble’s camera at a dark patch of sky, away from the outer-edge glow of our own galaxy and removed from the path of our planet, the Sun, or the Moon. This “empty” black canvas of space will eventually transform into a stunning cosmic mosaic of galaxies.
The first deep field image was captured in 1995. In order to see far beyond nearby galaxies, Hubble’s camera focused on a relatively empty patch of sky within the constellation Ursa Major. The results were this step-shaped image, an extraordinary display of nearly 3,000 galaxies spread across billions of light-years, featuring some of the earliest galaxies to emerge shortly after the big bang.
The universe is vast, and peering back billions of years takes time. Compared to Hubble’s typical exposure time of a few hours, deep fields can require hundreds of hours of exposure over several days. Patience is key. Capturing and combining several separate exposures allows astronomers to assemble a comprehensive core slice of our universe, providing key information about galaxy formation and evolution. Plus, by combining exposures from different wavelengths of light, astronomers are able to better understand galaxy distances, ages, and compositions.
The Hubble Ultra Deep Field is the deepest visible-light portrait of our universe. This astonishing display of nearly 10,000 galaxies was imaged over the course of 400 Hubble orbits around Earth, with a total of 800 exposures captured over 11.3 days.
The ability to see across billions of light-years and observe the farthest known galaxies in our universe requires access to wavelengths beyond those visible to the human eye. The universe is expanding and light from distant galaxies is stretched far across space, taking a long time to reach us here on Earth. This phenomenon, known as “redshift,” causes longer wavelengths of light to appear redder the farther they have to travel through space. Far enough away, and the wavelengths will be stretched into infrared light. This is where Hubble’s infrared vision comes in handy. Infrared light allows us to observe light from some of the earliest galaxies in our universe and better understand the history of galaxy formation over time.
In 2009, Hubble observed the Ultra Deep Field in the infrared. Using the Near Infrared Camera and Multi-Object Spectrometer, astronomers gathered one of the deepest core samples of our universe and captured some of the most distant galaxies ever observed.
Apart from their remarkable beauty and impressive imagery, deep field images are packed with information, offering astronomers a cosmic history lesson billions of years back in time within a single portrait. Since light from distant galaxies takes time to reach us, these images allow astronomers to travel through time and observe these galaxies as they appear at various stages in their development. By observing Hubble’s deep field images, we can begin to discover the questions we’ve yet to ask about our universe.
Credit: NASA, ESA, R. Bouwens and G. Illingworth (University of California, Santa Cruz)
Hubble’s deep field images observe galaxies that emerged as far back as the big bang. This image of the Hubble Ultra Deep Field showcases 28 of over 500 early galaxies from when the universe was less than one billion years old. The light from these galaxies represent different stages in their evolution as their light travels through space to reach us.
Hubble’s deep fields have opened a window to a small portion of our vast universe, and future space missions will take this deep field legacy even further. With advancements in technologies and scientific instruments, we will soon have the ability to further uncover the unimaginable.
Slated for launch in late 2021, NASA’s James Webb Space Telescope will offer a new lens to our universe with its impressive infrared capabilities. Relying largely on the telescope’s mid-infrared instrument, Webb will further study portions of the Hubble deep field images in greater detail, pushing the boundaries of the cosmic frontier even further.
And there you have it, Hubble’s guide to unlocking the secrets of the cosmos! To this day, deep field images remain fundamental building blocks for studying galaxy formation and deepening not only our understanding of the universe, but our place within it as well.
Still curious about Hubble Deep Fields? Explore more and follow along on Twitter, Facebook, and Instagram with #DeepFieldWeek!
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Ctenophora, Comb Jellies
Leedsichthys is a giant member of the Pachycormidae, an extinct group of Mesozoic bony fish, that lived in the oceans of the Middle Jurassic period. The first remains of Leedsichthys were identified in the nineteenth century. Leedsichthys fossils have been found in England, France, Germany and Chile. Along with its close pachycormid relatives Bonnerichthys and Rhinconichthys, Leedsichthys is part of a lineage of large-sized filter-feeders who swam the Mesozoic seas for over 100 million years, from the middle Jurassic until the end of the Cretaceous period. Pachycormids might represent an early branch of Teleostei, the group most modern bony fishes belong to; in that case Leedsichthys is the largest known teleost fish.
Leedsichthys fossils have been difficult to interpret, because the skeletons were not completely made of bone. Large parts consisted of cartilage that did not fossilise. On several occasions the enigmatic large partial remains have been mistaken for stegosaurian dinosaur bones. As the vertebrae are among the parts that have not been preserved, it is hard to determine the total body length. Estimates have varied wildly. At the beginning of the twentieth century a length of nine metres was seen as plausible, but by its end Leedsichthys was sometimes claimed to have been over thirty metres long. Recent research has lowered this to about sixteen meters for the largest individuals. Skull bones have been found indicating that Leedsichthys had a large head with bosses on the skull roof. Fossilised bony finrays show large elongated pectoral fins and a tall vertical tail fin. The gill arches were lined by gill rakers, equipped by a unique system of delicate bone plates, that filtered plankton from the sea water, the main food source.
I really wish people would jump on the marine exploration bandwagon as much as space exploration.
Scientists have only recently discovered that this type of plankton glows when they are moved because of stress - ironic when you consider how relaxing the sight of the shimmering waves are in the dark night. Bioluminescence is used as a defence mechanism to draw predators towards the creature trying to eat the plankton. The tiny flashes of light also disorientate and surprise the predator.
These tiny organisms produce light using a chemical called luciferin. The process of creating a bioluminescent light, which is simply light produced within a living creature, differs between organisms. Some need a particular food or another creature for the effect to happen. But this type of plankton, called dinoflagellates, produce luciferin on their own. The light the tiny plankton emit is called ‘cold light’, meaning less than 20% of the light generates heat.
Huge areas of the ocean can become populated by glowing plankton but the effect is especially common in warm-water lagoons that have narrow openings to the sea. This causes the plankton to gather and become trapped, causing the water to turn orange.
Image credit: Will Ho, Kin Cheung, Landscapes Maldives & eyegami
Source: Kuoni
After about a decade of slowly making friends with all the local crows in our neighborhood by feeding them peanuts when we go out walking, and putting peanuts out on our porch when they’re watching us, about three years back a pair of crows started bringing their fledgling by our porch to get peanuts. He was nervous at first but they showed him that it was safe and led him through the steps of cautiously getting nuts. Like one of his parents (we’re using male pronouns out of laziness, we can’t actually tell the gender of any of the crows), he has a funny habit of ruffling up his feathers into a big puff-ball, something we’ve really only seen this one and his parent do. We called his parent Fluffy because of this habit, so the fledgling was dubbed Fluffy Junior, often called just Junior.
Junior grew up coming by our porch for peanut treats, and following Jack and me when we go out walking. He’s easy to pick out because he’s far less skittish around us than any of the other crows who come to us for treats, and because he’s continued to do the fluff-ball thing. At first he came along with his parents, and then eventually just him, and then last winter he started bringing another crow along with him who was a lot more nervous around us than Junior or his parents had ever been.
Then for awhile this spring, we were only seeing Junior or his very skittish mate, never both of them together, and about two weeks back we finally found out why – Junior has a fledgling! They brought the baby over to the rooftop that’s across from our porch and fed him there, within easy access of the porch treats. The crow we’ve known since he was a baby now has a baby of his very own, and is carrying on the tradition of introducing the baby to us young.
So today we could hear Junior and his mate feeding the baby across the way – and if you’ve never heard crow fledglings being fed, it’s a very distinctive noise that sounds like a crow is being loudly strangled, and if you see it in process, you’ll notice that one crow has a much smaller beak that opens much wider and is bright red on the inside. When you know what to listen and look for, you can pretty easily spot fledglings being fed this time of the year, and often hear it from as much as a block away.
We want to encourage Junior to keep bringing his mate and their baby over to our place (and hopefully outlast the work-from-home era of our hateful neighbor who comes outside and claps at the birds when they make too much noise), so we put out some peanuts and a little bit of cheese for them, which is their absolute all time favorite treat.
We figured Junior or his mate would get the food and continue to feed their baby on the roof like they’ve done frequently since the beginning of the month, but instead the entire family of three flew over and landed on our porch, and fed the baby right there, about four feet from our door, while Jack and I hid behind the curtains to get a look without spooking them.
That’s a show of trust that not even Junior’s parents attempted, and it’s so exciting to think that this third generation of this little family will grow up that comfortable with being so close to us. They’re still rightfully skittish about being watched too closely, and we would never try to approach them or touch them, but it is lovely to get to see them behaving so calmly from such a close distance.
Gosh I love my crows.
Okay, the title of The Atlantic’s article might be a little click-bait-y. But the discovery is truly remarkable. A new bone has been analyzed from the already-famous cave in Russia, and it belonged to, per DNA analysis, the daughter of a Neanderthal mother and a Denisovan father.
Amateur astronomer, owns a telescope. This is a side blog to satiate my science-y cravings! I haven't yet mustered the courage to put up my personal astro-stuff here. Main blog : @an-abyss-called-life
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