Saturn at Night via NASA https://ift.tt/3E7x1m1
M31 Galaxy.
A Universe of Galaxies
Our Milky Way is almost unimaginably large, the distance even to the nearest of the 100 billion other stars in our galaxy, so far away, even a human life time wouldn't be enough to reach it, even if we invented something that could sustain and carry us that far.
So, trying to then expand that picture out to a universal level, to the trillions of galaxies that actually exist, billions of light years away from us is really hard to represent in a meaningful way.
Yesterday's APOD has this image with a magnifying glass that shows you the distance of each speck of light on this image, it also plays tunes depending on the distance.
IC 2118, Witch Nebula
What is this dark spot in the center of the image?
This NASA/ESA Hubble Space Telescope image features the star cluster Trumpler 14. One of the largest gatherings of hot, massive and bright stars in the Milky Way, this cluster houses some of the most luminous stars in our entire galaxy.
The prominent dark patch, close to the centre of the cluster is a so called Bok globule: this is an isolated and relatively small dark nebula, containing dense dust and gas. These objects are still subjects of intense research as their structure and density remains somewhat a mystery.
Credit: NASA & ESA, Jesús Maíz Apellániz (Centro de Astrobiología, CSIC-INTA, Spain)
Stars Make Firework Supplies!
The next time you see fireworks, take a moment to celebrate the cosmic pyrotechnics that made them possible. From the oxygen and potassium that help fireworks burn to the aluminum that makes sparklers sparkle, most of the elements in the universe wouldn’t be here without stars.
From the time the universe was only a few minutes old until it was about 400 million years old, the cosmos was made of just hydrogen, helium and a teensy bit of lithium. It took some stellar activity to produce the rest of the elements!
Stars are element factories
Even after more than 13 billion years, the hydrogen and helium that formed soon after the big bang still make up over 90 percent of the atoms in the cosmos. Most of the other elements come from stars.
Stars began popping into the universe about 400 million years after the big bang. That sounds like a long time, but it’s only about 3% of the universe’s current age!
Our Nancy Grace Roman Space Telescope will study the universe’s early days to help us learn more about how we went from a hot, soupy sea of atoms to the bigger cosmic structures we see today. We know hydrogen and helium atoms gravitated together to form stars, where atoms could fuse together to make new elements, but we're not sure when it began happening. Roman will help us find out.
The central parts of atoms, called nuclei, are super antisocial – it takes a lot of heat and pressure to force them close together. Strong gravity in the fiery cores of the first stars provided just the right conditions for hydrogen and helium atoms to combine to form more elements and generate energy. The same process continues today in stars like our Sun and provides some special firework supplies.
Carbon makes fireworks explode, helps launch them into the sky, and is even an ingredient in the “black snakes” that seem to grow out of tiny pellets. Fireworks glow pink with help from the element lithium. Both of these elements are created by average, Sun-like stars as they cycle from normal stars to red giants to white dwarfs.
Eventually stars release their elements into the cosmos, where they can be recycled into later generations of stars and planets. Sometimes they encounter cosmic rays, which are nuclei that have been boosted to high speed by the most energetic events in the universe. When cosmic rays collide with atoms, the impact can break them apart, forming simpler elements. That’s how we get boron, which can make fireworks green, and beryllium, which can make them silver or white!
Since massive stars have even stronger gravity in their cores, they can fuse more elements – all the way up to iron. (The process stops there because instead of producing energy, fusing iron is so hard to do that it uses up energy.)
That means the sodium that makes fireworks yellow, the aluminum that produces silver sparks (like in sparklers), and even the oxygen that helps fireworks ignite were all first made in stars, too! A lot of these more complex elements that we take for granted are actually pretty rare throughout the cosmos, adding up to less than 10 percent of the atoms in the universe combined!
Fusion in stars only got us through iron on the periodic table, so where do the rest of our elements come from? It’s what happens next in massive stars that produces some of the even more exotic elements.
Dying stars make elements too!
Once a star many times the Sun’s mass burns through its fuel, gravity is no longer held in check, and its core collapses under its own weight. There, atoms are crushed extremely close together – and they don’t like that! Eventually it reaches a breaking point and the star explodes as a brilliant supernova. Talk about fireworks! These exploding stars make elements like copper, which makes fireworks blue, and zinc, which creates a smoky effect.
Something similar can happen when a white dwarf star – the small, dense core left behind after a Sun-like star runs out of fuel – steals material from a neighboring star. These white dwarfs can explode as supernovae too, spewing elements like the calcium that makes fireworks orange into the cosmos.
When stars collide
White dwarfs aren’t the only “dead” stars that can shower their surroundings with new elements. Stars that are too massive to leave behind white dwarfs but not massive enough to create black holes end up as neutron stars.
If two of these extremely dense stellar skeletons collide, they can produce all kinds of elements, including the barium that makes fireworks bright green and the antimony that creates a glitter effect. Reading this on a phone or computer? You can thank crashing dead stars for some of the metals that make up your device, too!
As for most of the remaining elements we know of, we've only seen them in labs on Earth so far.
Sounds like we’ve got it all figured out, right? But there are still lots of open questions. Our Roman Space Telescope will help us learn more about how elements were created and distributed throughout galaxies. That’s important because the right materials had to come together to form the air we breathe, our bodies, the planet we live on, and yes – even fireworks!
So when you’re watching fireworks, think about their cosmic origins!
Learn more about the Roman Space Telescope at: https://roman.gsfc.nasa.gov/
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
NASA Has Eyes on the Universe via NASA https://ift.tt/2RTThcv
Galactic refurbishment by Hubble Space Telescope / ESA
The smudge of stars at the centre of this NASA/ESA Hubble Space Telescope image is a galaxy known as UGC 5797. UGC 5797 is an emission line galaxy, meaning that it is currently undergoing active star formation. The result is a stellar population that is constantly being refurbished as massive bright blue stars form. Galaxies with prolific star formation are not only veiled in a blue tint, but are key to the continuation of a stellar cycle.
In this image UGC 5797 appears in front of a background of spiral galaxies. Spiral galaxies have copious amounts of dust and gas — the main ingredient for stars — and therefore often also belong to the class of emission line galaxies.
Spiral galaxies have disc-like shapes that drastically vary in appearance depending on the angle at which they are observed. The collection of spiral galaxies in this frame exhibits this attribute acutely: Some are viewed face-on, revealing the structure of the spiral arms, while the two in the bottom left are seen edge-on, appearing as plain streaks in the sky. There are many spiral galaxies, with varying colours and at different angles sprinkled across this image — just take a look.
A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by Luca Limatola.
M2 9: Wings of a Butterfly Nebula via NASA https://ift.tt/3kaHqmi
Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and M2-9 pictured here, the stars transform themselves from normal stars to white dwarfs by casting off their outer gaseous envelopes. The expended gas frequently forms an impressive display called a planetary nebula that fades gradually over thousands of years. M2-9, a butterfly planetary nebula 2100 light-years away shown in representative colors, has wings that tell a strange but incomplete tale. In the center, two stars orbit inside a gaseous disk 10 times the orbit of Pluto. The expelled envelope of the dying star breaks out from the disk creating the bipolar appearance. Much remains unknown about the physical processes that cause and shape planetary nebulae.
(Published September 13, 2020)
Possible sign of life on Venus
Phosphine Detected In The Atmosphere of Venus - An Indicator of Possible Life?
Astronomers detected signs of a smelly, toxic gas that microbes can make in the planet’s clouds.
Chemical signs of the gas phosphine have been spotted in observations of the Venusian atmosphere, researchers report September 14 in Nature Astronomy. Examining the atmosphere in millimeter wavelengths of light showed that the planet’s clouds appear to contain up to 20 parts per billion of phosphine — enough that something must be actively producing it, the researchers say.
If the discovery holds up, and if no other explanations for the gas are found, then the hellish planet next door could be the first to yield signs of extraterrestrial life — though those are very big ifs!
The presence of phosphine is seen by many astrobiologists as a “biosignature” i.e. an indicator of the possible presence of life. The detection was made by the Atacama (ALMA) array located in Chile and the James Clerk Maxwell telescope located in Hawaii. The research team includes members from the University of Manchester, the Massachusetts Institute of Technology, and Cardiff University. A paper will appear in the 14 September issue of Nature Astronomy.
2020 September 15
Biomarker Phosphine Discovered in the Atmosphere of Venus Image Credit: ISAS, JAXA, Akatsuki; Processing: Meli thev
Explanation: Could there be life floating in the atmosphere of Venus? Although Earth’s planetary neighbor has a surface considered too extreme for any known lifeform, Venus’ upper atmosphere may be sufficiently mild for tiny airborne microbes. This usually disfavored prospect took an unexpected upturn yesterday with the announcement of the discovery of Venusian phosphine. The chemical phosphine (PH3) is a considered a biomarker because it seems so hard to create from routine chemical processes thought to occur on or around a rocky world such as Venus – but it is known to be created by microbial life on Earth. The featured image of Venus and its thick clouds was taken in two bands of ultraviolet light by the Venus-orbing Akatsuki, a Japanese robotic satellite that has been orbiting the cloud-shrouded world since 2015. The phosphine finding, if confirmed, may set off renewed interest in searching for other indications of life floating high in the atmosphere of our Solar System’s second planet out from the Sun.
∞ Source: apod.nasa.gov/apod/ap200915.html
Hubble Stows a Pocketful of Stars via NASA https://ift.tt/3iqlYJy
archae-heart-deactivated2021012
deep space
The Pleiades, Seven Sisters
