#Astronomical Spectroscopy

[planetariumhub]

Unveiling the Cosmic Remnant: Exploring the Crab Nebula (M1)

Credits: NASA, ESA, J. Hester and A. Loll (Arizona State University) Among the fascinating remnants of stellar explosions, the Crab Nebula, also known as Messier 1 (M1), stands as a testament to the immense forces that shape our universe. Located in the constellation Taurus, this celestial spectacle has captivated astronomers and enthusiasts alike for centuries. In this article, we embark on a…

[thepastisalreadywritten]

By Allie Yang

10 August 2023

Two of our galaxy’s most famous stars were recently photobombed by what appears to be a celestial question mark.

The symbol was spotted in a new image from the James Webb Space Telescope (JWST) of the forming stars Herbig-Haro 46/47, which are well-known and have been frequently observed by astronomers.

These two stars can provide clues about how our own sun may have formed.

They’re relatively close to Earth, about 1,400 light-years, and relatively young, only a few thousand years old.

In fact, they’re still in gestation and have not technically been “born” yet, which is marked when the stars start shining from their own nuclear fusion.

The image is the first of the twin protostars from the NIRCam instrument on JWST.

It was captured using infrared light, which penetrates space dust more easily than visual light, and it is the highest resolution image of the objects ever seen at these wavelengths.

The telescope’s astonishing sensitivity allowed the glowing red question mark to be captured in the lower center of the image.

The object is far outside our galactic neighborhood, possibly billions of light-years away, says Christopher Britt, an education and outreach scientist at the Space Telescope Science Institute who helped plan these observations.

His best guess is that the question mark is actually two galaxies merging.

“That's something that's seen fairly frequently, and it happens to galaxies many times over the course of their lives,” he says.

“That includes our own galaxy, the Milky Way … [it] will merge with Andromeda in about four billion years or so.”

The hints pointing to two galaxies are found in the question mark’s strange shape.

There are two brighter spots, one in the curve and the other in the dot, which could be the galactic nuclei, or the centers of the galaxies, Britt says.

The curve of the question mark might be the “tails” being stripped off as the two galaxies spiral toward each other.

“It's very cute. It's a question mark … But you can find the colons and semicolons, and any other punctuation mark, because you have 10,000 little smudges of light in each image taken every half hour,” says David Helfand, an astronomer at Columbia University.

The sheer number of shining objects we find are bound to create some serendipitous images, and our brains have evolved to find those patterns, he says.

Astronomers have seen similar objects closer to home.

Two merging galaxies captured by the Hubble Space Telescope in 2008 also look like a question mark, just turned 90 degrees.

Helfand says the question mark seems to be two objects, the curve and the dot, but could be more that just happened to line up.

They could also be completely unrelated objects, he says, if one is much closer to Earth than the other.

Britt warns that estimating distance based only on colors in the image can be tricky.

The red of the question mark could mean it’s very far away (light waves stretch as they travel through the expanding universe, shifting to redder wavelengths) or that it’s closer and obscured by dust near the object.

It would take more investigation to identify exactly how far away the question mark is.

This could be done by measuring photometric redshifts, determined by the brightness observed through different filters, but this would only provide an estimate for the distance, Britt says.

Spectroscopy, which analyzes light from the source to determine its elemental makeup, could provide a more exact distance but requires a separate instrument to measure.

Given the number of intriguing targets spotted by JWST, the question mark may never receive this treatment.

For now, the source of this symbol in the sky remains a cosmic mystery.

[nasa]

A Tour of Cosmic Temperatures

We often think of space as “cold,” but its temperature can vary enormously depending on where you visit. If the difference between summer and winter on Earth feels extreme, imagine the range of temperatures between the coldest and hottest places in the universe — it’s trillions of degrees! So let’s take a tour of cosmic temperatures … from the coldest spots to the hottest temperatures yet achieved.

First, a little vocabulary: Astronomers use the Kelvin temperature scale, which is represented by the symbol K. Going up by 1 K is the same as going up 1°C, but the scale begins at 0 K, or -273°C, which is also called absolute zero. This is the temperature where the atoms in stuff stop moving. We’ll measure our temperatures in this tour in kelvins, but also convert them to make them more familiar!

We’ll start on the chilly end of the scale with our CAL (Cold Atom Lab) on the International Space Station, which can chill atoms to within one ten billionth of a degree above 0 K, just a fraction above absolute zero.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Just slightly warmer is the Resolve sensor inside XRISM, pronounced “crism,” short for the X-ray Imaging and Spectroscopy Mission. This is an international collaboration led by JAXA (Japan Aerospace Exploration Agency) with NASA and ESA (European Space Agency). Resolve operates at one twentieth of a degree above 0 K. Why? To measure the heat from individual X-rays striking its 36 pixels!

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Resolve and CAL are both colder than the Boomerang Nebula, the coldest known region in the cosmos at just 1 K! This cloud of dust and gas left over from a Sun-like star is about 5,000 light-years from Earth. Scientists are studying why it’s colder than the natural background temperature of deep space.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Let’s talk about some temperatures closer to home. Icy gas giant Neptune is the coldest major planet. It has an average temperature of 72 K at the height in its atmosphere where the pressure is equivalent to sea level on Earth. Explore how that compares to other objects in our solar system!

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

How about Earth? According to NOAA, Death Valley set the world’s surface air temperature record on July 10, 1913. This record of 330 K has yet to be broken — but recent heat waves have come close. (If you’re curious about the coldest temperature measured on Earth, that’d be 183.95 K (-128.6°F or -89.2°C) at Vostok Station, Antarctica, on July 21, 1983.)

We monitor Earth's global average temperature to understand how our planet is changing due to human activities. Last year, 2023, was the warmest year on our record, which stretches back to 1880.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

The inside of our planet is even hotter. Earth’s inner core is a solid sphere made of iron and nickel that’s about 759 miles (1,221 kilometers) in radius. It reaches temperatures up to 5,600 K.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We might assume stars would be much hotter than our planet, but the surface of Rigel is only about twice the temperature of Earth’s core at 11,000 K. Rigel is a young, blue star in the constellation Orion, and one of the brightest stars in our night sky.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger 

We study temperatures on large and small scales. The electrons in hydrogen, the most abundant element in the universe, can be stripped away from their atoms in a process called ionization at a temperature around 158,000 K. When these electrons join back up with ionized atoms, light is produced. Ionization is what makes some clouds of gas and dust, like the Orion Nebula, glow.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We already talked about the temperature on a star’s surface, but the material surrounding a star gets much, much hotter! Our Sun’s surface is about 5,800 K (10,000°F or 5,500°C), but the outermost layer of the solar atmosphere, called the corona, can reach millions of kelvins.

Our Parker Solar Probe became the first spacecraft to fly through the corona in 2021, helping us answer questions like why it is so much hotter than the Sun's surface. This is one of the mysteries of the Sun that solar scientists have been trying to figure out for years.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Looking for a hotter spot? Located about 240 million light-years away, the Perseus galaxy cluster contains thousands of galaxies. It’s surrounded by a vast cloud of gas heated up to tens of millions of kelvins that glows in X-ray light. Our telescopes found a giant wave rolling through this cluster’s hot gas, likely due to a smaller cluster grazing it billions of years ago.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Now things are really starting to heat up! When massive stars — ones with eight times the mass of our Sun or more — run out of fuel, they put on a show. On their way to becoming black holes or neutron stars, these stars will shed their outer layers in a supernova explosion. These layers can reach temperatures of 300 million K!

Credit: NASA's Goddard Space Flight Center/Jeremy Schnittman

We couldn’t explore cosmic temperatures without talking about black holes. When stuff gets too close to a black hole, it can become part of a hot, orbiting debris disk with a conical corona swirling above it. As the material churns, it heats up and emits light, making it glow. This hot environment, which can reach temperatures of a billion kelvins, helps us find and study black holes even though they don’t emit light themselves.

JAXA’s XRISM telescope, which we mentioned at the start of our tour, uses its supercool Resolve detector to explore the scorching conditions around these intriguing, extreme objects.

Credit: NASA's Goddard Space Flight Center/CI Lab

Our universe’s origins are even hotter. Just one second after the big bang, our tiny, baby universe consisted of an extremely hot — around 10 billion K — “soup” of light and particles. It had to cool for a few minutes before the first elements could form. The oldest light we can see, the cosmic microwave background, is from about 380,000 years after the big bang, and shows us the heat left over from these earlier moments.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We’ve ventured far in distance and time … but the final spot on our temperature adventure is back on Earth! Scientists use the Large Hadron Collider at CERN to smash teensy particles together at superspeeds to simulate the conditions of the early universe. In 2012, they generated a plasma that was over 5 trillion K, setting a world record for the highest human-made temperature.

Want this tour as a poster? You can download it here in a vertical or horizontal version!

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Explore the wonderful and weird cosmos with NASA Universe on X, Facebook, and Instagram. And make sure to follow us on Tumblr for your regular dose of space!

[mindblowingscience]

Using the James Webb Space Telescope (JWST), astronomers from the Space Telescope Science Institute (STScI) in Baltimore, Maryland and elsewhere have conducted transmission spectroscopy of a nearby super-Earth exoplanet known as L98-59 d. Results of these observations, available in a research paper published August 28 on the pre-print server arXiv, suggest that the planet has a sulfur-rich atmosphere. L98-59 is a bright M-dwarf star located some 34.6 light years away. It is known to be orbited by at least four planets, and one of them is L98-59 d—a super-Earth about 58% larger than the Earth, with a mass of 2.31 Earth masses. L98-59 d orbits its host every 7.45 days, at a distance of approximately 0.05 AU. The planet's equilibrium temperature is estimated to be 416 K.

Continue Reading.

[quiltofstars]

Roaming the Mineral-Rich Southern Lunar Terrain // Alien_Enthusiast

Read below the cut for some info about which craters are featured and a map to help identify them!

In birth order of their eponyms:

Purbach crater is named after Austrian astronomer Georg von Peuerbach (1423-1461) who aimed at making astronomy accessible for the average European during the Renaissance with his textbook, Theoricae Novae Planetarum.

Walther crater is named after the German merchant Bernhard Walther (1430-1504) who was a noted observer of the motions of the planets.

Regiomontanus crater is named after German mathematician Johannes Müller von Königsberg (1436-1476) who helped develop the heliocentric theory of the solar system with trigonometry.

Orontius crater is named after the French mathematician Oronce Finé (1494-1555) who published an astronomy textbook De mundi sphaera which guided readers on the use of equipment and proper astronomy methods.

Nonius crater is named for Pedro Nunes (1502-1578), a Portuguese mathematician who used trigonometry to make improvements to the geocentric model of the solar system.

Hell crater is not named after the land of Satan, but instead is named after Hungarian astronomer Maximilian Hell (1720-1792) who was the director of the Vienna Observatory and observed the 1769 transit of Venus.

Lexell crater is named after the Finnish astronomer Andres Johan Lexell (1740-1784), a prolific member of the Russian Academy of Sciences who made important discoveries in celestial mechanics. He was the first to prove that Uranus was a planet rather than a comet.

Miller crater is named after William Allen Miller (1817-1870), a British chemist who aided William Huggins in studying the spectra of astronomical objects, primarily stars.

Huggins crater is named after the British astronomer William Huggins (1824-1910) who pioneered the realm of astronomical spectroscopy, becoming the first to take the spectrum of a planetary nebula.

Bell crater is named after none other than Canadian inventor Alexander Graham Bell (1847-1922) most famous for inventing the telephone, but who also had inventions in aeronautics.

Deslandres crater is named for Henri Alexandre Deslandres (1853-1948), a French astronomer who was the director of the Paris Observatories and carried out studies on the atmosphere of the Sun.

[spacetelescopescience]

The James Webb Space Telescope's Mid-Infrared Instrument (MIRI) provides imaging and spectroscopy capabilities in the mid-infrared, letting astronomers study cooler objects like debris disks and extremely distant galaxies. More about what MIRI can uniquely observe: https://webbtelescope.pub/4g1LrqU

[livingforstars]

Helios Helium - May 20th, 1996.

"Above is an image of the relatively quiet Sun made on May 18th, 1996, in light emitted by ionised helium atoms in the Solar chromosphere. Helium was first discovered in the Sun in 1868, its name fittingly derived from the Greek word Helios, meaning Sun. Credit for the discovery goes to astronomer Joseph Lockyer. Lockyer relied on a developed technique of spectroscopy, dissecting sunlight into a spectrum, and the idea that each element produces a characteristic spectral pattern of bright lines. He noticed a yellow line in a solar spectrum made during an eclipse which could not be accounted for by elements known on Earth. Almost 27 years later, helium was finally discovered on Earth when the spectrum of a helium bearing mineral of uranium provided an exact match to the previously detected element of the Sun. Helium is now known to be the second most abundant element (after hydrogen) in the Universe."

[wumblr]

at some point the k218b dimethyl sulfide paper is going to get published and every astronomer in the world is going to slew in your direction like "oh so you finally heard about that" and then they will pull out a folder of outreach curricula on spectroscopy and dimethyl sulfide formation pathways that they've been preparing for the past couple years. so watch out for that

[stay-with-wonder]

Eta Carinae

Eta Carinae: A Stellar Beauty

In the vast expense of our universe, where stars twinkle like celestial gems, there lies a dazzling beauty named Eta Carinae. Prepare to be captivated as I take you on a journey to discover the secrets of this cosmic wonder.

Eta Carinae, known lovingly as “Eta” by astronomers, is a stellar masterpiece in the Carina Nebula, approximately 7.500 light-years away from Earth. This stellar gem has captivated astronomers for centuries with its majestic presence and intriguing nature.

A Star Like No Other

Eta Carinae is not your ordinary star-it’s a binary star system consisting of two massive, luminous stars locked in an intricate cosmic dance. These stars Eta Carinae A and Eta Carinae B -creative names, I know- are classified as hypergiants, making them some of the most massive and brightest stars. (that we know of)

Historic Outbursts

  Since then, Eta Carinae has experienced smaller-scale eruptions, displaying irregular brightness variations and releasing enormous amounts of energy.

Impending Supernova:

One of the most captivating aspects of Eta Carinae is the potential for a future supernova event. The massive star is nearing the end of its life, and astronomers anticipate that it will eventually explode in a spectacular supernova. When this cataclysmic event occurs, it is expected to release an immense amount of energy, briefly outshining its host galaxy. The timing of this explosion remains uncertain, adding to the intrigue and urgency of studying Eta Carinae.

Understanding the Phenomenon:

The erratic behavior and imminent explosion of Eta Carinae pose intriguing questions for scientists. Studying this stellar system provides valuable insights into the evolution and fate of massive stars. Astronomers employ various observational techniques, including spectroscopy, imaging, and monitoring of brightness fluctuations, to unravel the physical processes at play within Eta Carinae. By analyzing the data collected over decades, researchers hope to decipher the mechanisms driving its eruptions and better predict the timing of its impending supernova.

Implications for the Universe:

Eta Carinae's significance extends beyond its individuality. Massive stars like Eta Carinae play a pivotal role in shaping galaxies and enriching the cosmos with heavy elements. Supernova explosions from such stars distribute these elements throughout the universe, ultimately contributing to the formation of new stars, planets, and even life. Understanding the life cycle of massive stars through the study of objects like Eta Carinae enhances our knowledge of cosmic evolution on a grand scale.

[spacetimewithstuartgary]

Black hole in early universe appears to be consuming matter at over 40 times its theoretical limit

Supermassive black holes exist at the center of most galaxies, and modern telescopes continue to observe them at surprisingly early times in the universe's evolution.

It's difficult to understand how these black holes were able to grow so big so rapidly. But with the discovery of a low-mass supermassive black hole feasting on material at an extreme rate, seen just 1.5 billion years after the Big Bang, astronomers now have valuable new insights into the mechanisms of rapidly growing black holes in the early universe.

LID-568 was discovered by a cross-institutional team of astronomers led by International Gemini Observatory/NSF NOIRLab astronomer Hyewon Suh. They used the James Webb Space Telescope (JWST) to observe a sample of galaxies from the Chandra X-ray Observatory's COSMOS legacy survey.

This population of galaxies is very bright in the X-ray part of the spectrum, but are invisible in the optical and near-infrared. JWST's unique infrared sensitivity allows it to detect these faint counterpart emissions.

LID-568 stood out within the sample for its intense X-ray emission, but its exact position could not be determined from the X-ray observations alone, raising concerns about properly centering the target in JWST's field of view.

So, rather than using traditional slit spectroscopy, JWST's instrumentation support scientists suggested that Suh's team use the integral field spectrograph on JWST's NIRSpec. This instrument can get a spectrum for each pixel in the instrument's field of view rather than being limited to a narrow slice.

"Owing to its faint nature, the detection of LID-568 would be impossible without JWST. Using the integral field spectrograph was innovative and necessary for getting our observation," says Emanuele Farina, International Gemini Observatory/NSF NOIRLab astronomer and co-author of the paper, "A super-Eddington-accreting black hole ~1.5 Gyr after the Big Bang observed with JWST," appearing in Nature Astronomy.

JWST's NIRSpec allowed the team to get a full view of their target and its surrounding region, leading to the unexpected discovery of powerful outflows of gas around the central black hole. The speed and size of these outflows led the team to infer that a substantial fraction of the mass growth of LID-568 may have occurred in a single episode of rapid accretion.

"This serendipitous result added a new dimension to our understanding of the system and opened up exciting avenues for investigation," says Suh.

In a stunning discovery, Suh and her team found that LID-568 appears to be feeding on matter at a rate 40 times its Eddington limit. This limit relates to the maximum luminosity that a black hole can achieve, as well as how fast it can absorb matter, such that its inward gravitational force and outward pressure generated from the heat of the compressed, infalling matter remain in balance.

When LID-568's luminosity was calculated to be so much higher than theoretically possible, the team knew they had something remarkable in their data.

"This black hole is having a feast," says International Gemini Observatory/NSF NOIRLab astronomer and co-author Julia Scharwächter.

"This extreme case shows that a fast-feeding mechanism above the Eddington limit is one of the possible explanations for why we see these very heavy black holes so early in the universe."

These results provide new insights into the formation of supermassive black holes from smaller black hole "seeds," which current theories suggest arise either from the death of the universe's first stars (light seeds) or the direct collapse of gas clouds (heavy seeds). Until now, these theories lacked observational confirmation.

"The discovery of a super-Eddington accreting black hole suggests that a significant portion of mass growth can occur during a single episode of rapid feeding, regardless of whether the black hole originated from a light or heavy seed," says Suh.

The discovery of LID-568 also shows that it's possible for a black hole to exceed its Eddington limit, and provides the first opportunity for astronomers to study how this happens.

It's possible that the powerful outflows observed in LID-568 may be acting as a release valve for the excess energy generated by the extreme accretion, preventing the system from becoming too unstable. To further investigate the mechanisms at play, the team is planning follow-up observations with JWST.

TOP IMAGE: This artist's illustration shows a red, early-universe dwarf galaxy that hosts a rapidly feeding black hole at its center. Using data from NASA's JWST and Chandra X-ray Observatory, a team of U.S. National Science Foundation NOIRLab astronomers have discovered this low-mass black hole at the center of a galaxy just 1.5 billion years after the Big Bang. It is accreting matter at a phenomenal rate — over 40 times the theoretical limit. While short lived, this black hole's 'feast' could help astronomers explain how supermassive black holes grew so quickly in the early universe. Credit: NOIRLab/NSF/AURA/J. da Silva/M. Zamani

LOWER IMAGE: This artist's illustration shows a rapidly feeding black hole that is emitting powerful gas outflows. Using data from NASA's JWST and Chandra X-ray Observatory, a team of U.S. National Science Foundation NOIRLab astronomers have discovered this low-mass black hole at the center of a galaxy just 1.5 billion years after the Big Bang. It is accreting matter at a phenomenal rate—over 40 times the theoretical limit. While short lived, this black hole's 'feast' could help astronomers explain how supermassive black holes grew so quickly in the early universe. Credit: NOIRLab/NSF/AURA/J. da Silva/M. Zamani

[petervintonjr]

"I had no role models because nobody ever publicized them, not that they didn't exist. George Washington Carver and Percy Julian and others had preceded me in science, but nobody ever publicized their accomplishments, and, therefore, many of the minority students didn't know that they had a future in science because they figured it was something that was not for them."

After a bit of time away from this project to make room for convention appearances and other shows, I now return to the subject with a look at the life and accomplishments of physicist George Robert Carruthers, on this, what would have been his 85th birthday.

Born in 1939 Cincinnati, Carruthers's father was himself a civil engineer at Wright-Patterson AFB, but the family soon moved to the more rural location of Milford, Ohio. Carruthers was described as quiet and focused --intensely interested in space travel stories and comic books (my people!), and a devourer of the science articles in Collier's magazine (even penning a fan letter to Dr. Werner Von Braun, to which he received an unexpected and encouraging personal reply). At the age of ten Carruthers built his first telescope, constructed from lenses he obtained by mail order. After George's father died in 1952, the family moved to Chicago but his fascination with spaceflight did not diminish. Encouraged by wonderfully observant teachers, he eventually graduated from the University of Illinois, Urbana-Champaign in 1960, then earned his MS in in nuclear engineering in 1962, and then landed his PhD in aeronautical and astronautical engineering in 1964.

While working towards his PhD, Carruthers worked as a researcher and teaching assistant, studying plasma and gases. In 1964, Carruthers took a postdoctoral appointment with the Naval Research Laboratory (NRL) in Washington, D.C., focusing on far ultraviolet astronomy. In 1969 he received a U.S. patent for inventing a form of image converter; an instrument that detects electromagnetic radiation in short wavelengths. In 1970 his invention recorded the first observation of molecular hydrogen in outer space (which he described as "a very big deal at the time.")

Far and away (literally), Dr. Carruthers's greatest contribution to science is his development and construction of an ultraviolet electronographic telescope, which became the first (and to date still the only) astronomical instrument sent to the surface of the Moon; more properly known as the Far Ultraviolet Camera/Spectrograph. The camera was brought along on the Apollo 16 mission in 1972, set up to observe the Earth's geocorona (outermost atmosphere) from a vantage point never before possible. A short time later a variation on this very same camera was brought aboard Skylab to photograph the near approach of Comet Kohoutek, the first instance of a comet being recorded in ultraviolet. A flight backup of the Apollo 16 instrument, along with the original mission film canister, stood for many years as part of the lunar lander exhibit at the National Air & Space Museum, until it was later transferred to a more protected exhibit to guard against corrosion.

Dr. Carruthers's success and notoriety from the Apollo mission led to his creation of the Science & Engineers Apprentice Program, offering disadvantaged high school students the opportunity to work with scientists at the Naval Research Laboratory. His research into ultraviolet spectroscopy continued --in 1991 one of his ultraviolet cameras was used in multiple experiments aboard the Space Shuttle Discovery (STS-39). He retired from the NRL in 2002 and in 2003, was inducted into the National Inventor Hall of Fame. In 2013 was awarded the National Medal for Technology and Innovation by President Barack Obama. Dr. Carruthers died on Christmas Day, 2020.

[planetariumhub]

The Majestic Eagle Nebula (M16): Unveiling the Stellar Sculptor

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) In the depths of the cosmos lies a breathtaking celestial masterpiece known as the Eagle Nebula, or Messier 16 (M16). Located in the constellation Serpens, this nebula has captivated astronomers and stargazers with its stunning beauty and unique features. In this article, we will embark on a journey to explore the enigmatic Eagle…

[mysticstronomy]

IS QUASAR A BLACK HOLE??

Blog#289

Wednesday, April 19th, 2023

Welcome back,

A quasar is a supermassive black hole feeding on gas at the center of a distant galaxy.

Quasar is short for quasi-stellar radio source, because astronomers first discovered quasars in 1963 as objects that looked like stars but emitted radio waves.

Now, the term is a catch-all for all feeding, and therefore luminous supermassive black holes, also often called active galactic nuclei.

It’s a bit of a contradiction to call a black hole luminous; black holes themselves are, of course, black. In fact, almost every large galaxy hosts a black hole with the mass of millions to billions of Suns, and many of these black holes lurk in the dark. Our Milky Way’s behemoth weighs in at 4.3 million solar masses, but its starvation diet mutes all but faint flashes and flickers.

We know it’s there, though, from the orbits of stars around it. Other dormant black holes occasionally shred an infalling star, making their presence known by the flare of radiation that ensues.

But quasars are a different breed of black hole. They reside in galaxies with plentiful gas supplies, perhaps supplied by a recent galaxy-galaxy collision, and they gorge on the inflowing material.

The gas spirals around as it falls in, heating up in the process and emitting radiation across the electromagnetic spectrum.

Supermassive black holes in nearby galaxies typically do not have that much gas available to them, so quasars are typically found in distant galaxies. The nearest quasar is Markarian 231, which lies about 600 million light-years from Earth.

A quasar is not only the feeding black hole itself, but the light-producing structures that surround it. Visible and ultraviolet light come from the glowing disk of infalling material, while even hotter gas above the disk shines at X-ray energies. Jets shooting out along the black hole’s poles emit everything from radio waves to X-rays. Farther out from the black hole, the prolific dust and gas glow at infrared wavelengths.

The size of a quasar accretion disk, which scales with the mass of its black hole, is typically a few light-days across. That dwarfs in comparison to its host galaxy; the Milky Way for comparison is roughly 100,000 light-years across. Yet quasars often outshine their hosts.

Despite their brilliance, quasars are so small and distant that even the most powerful telescope cannot resolve all the structures within a quasar.

Astronomers have to ferret out the details using other techniques, such as analyzing spectroscopy (spreading out the light by wavelength) or light curves (spreading out the light by its arrival time).

While the details are still up for debate, we can use current knowledge to paint a general picture of a quasar. Just remember that this picture might change over time as we learn more!

Originally published on skyandtelescope.org

COMING UP!!

(Saturday, April 22nd, 2023)

"HOW LONG DO BLACK HOLES LAST??"

[nasa]

Black Scientists and Engineers Past and Present Enable NASA Space Telescope

The Nancy Grace Roman Space Telescope is NASA’s next flagship astrophysics mission, set to launch by May 2027. We’re currently integrating parts of the spacecraft in the NASA Goddard Space Flight Center clean room.

Once Roman launches, it will allow astronomers to observe the universe like never before. In celebration of Black History Month, let’s get to know some Black scientists and engineers, past and present, whose contributions will allow Roman to make history.

Dr. Beth Brown

The late Dr. Beth Brown worked at NASA Goddard as an astrophysicist. in 1998, Dr. Brown became the first Black American woman to earn a Ph.D. in astronomy at the University of Michigan. While at Goddard, Dr. Brown used data from two NASA X-ray missions – ROSAT (the ROentgen SATellite) and the Chandra X-ray Observatory – to study elliptical galaxies that she believed contained supermassive black holes.  

With Roman’s wide field of view and fast survey speeds, astronomers will be able to expand the search for black holes that wander the galaxy without anything nearby to clue us into their presence.

Dr. Harvey Washington Banks 

In 1961, Dr. Harvey Washington Banks was the first Black American to graduate with a doctorate in astronomy. His research was on spectroscopy, the study of how light and matter interact, and his research helped advance our knowledge of the field. Roman will use spectroscopy to explore how dark energy is speeding up the universe's expansion.

NOTE - Sensitive technical details have been digitally obscured in this photograph. 

Sheri Thorn 

Aerospace engineer Sheri Thorn is ensuring Roman’s primary mirror will be protected from the Sun so we can capture the best images of deep space. Thorn works on the Deployable Aperture Cover, a large, soft shade known as a space blanket. It will be mounted to the top of the telescope in the stowed position and then deployed after launch. Thorn helped in the design phase and is now working on building the flight hardware before it goes to environmental testing and is integrated to the spacecraft.

Sanetra Bailey 

Roman will be orbiting a million miles away at the second Lagrange point, or L2. Staying updated on the telescope's status and health will be an integral part of keeping the mission running. Electronics engineer Sanetra Bailey is the person who is making sure that will happen. Bailey works on circuits that will act like the brains of the spacecraft, telling it how and where to move and relaying information about its status back down to Earth.  

 Learn more about Sanetra Bailey and her journey to NASA. 

Dr. Gregory Mosby 

Roman’s field of view will be at least 100 times larger than the Hubble Space Telescope's, even though the primary mirrors are the same size. What gives Roman the larger field of view are its 18 detectors. Dr. Gregory Mosby is one of the detector scientists on the Roman mission who helped select the flight detectors that will be our “eyes” to the universe.

Dr. Beth Brown, Dr. Harvey Washington Banks, Sheri Thorn, Sanetra Bailey, and Dr. Greg Mosby are just some of the many Black scientists and engineers in astrophysics who have and continue to pave the way for others in the field. The Roman Space Telescope team promises to continue to highlight those who came before us and those who are here now to truly appreciate the amazing science to come. 

To stay up to date on the mission, check out our website and follow Roman on X and Facebook.

Make sure to follow us on Tumblr for your regular dose of space!

[blueiscoool]

Yerkes Observatory

Yerkes Observatory, astronomical observatory located at Williams Bay on Lake Geneva in southeastern Wisconsin, U.S. The Yerkes Observatory of the University of Chicago was named for its benefactor, transportation magnate Charles T. Yerkes, and was opened in 1897. It contains the largest refracting telescope (40 inches [1 metre]) in the world. The refractor has been used for solar and stellar spectroscopy, photographic parallaxes, and double-star observations, while other more modern telescopes at the site have been equipped for photoelectric, polarimetric, and spectroscopic applications.

[ryan-sometimes]

As a chem student, I love stories of element discoveries. Especially the serendipitous ones. My favourite is probably how we discovered helium!

We use spectroscopy as a way to uniquely identify elements. As you might know, light exists as a continuous spectrum, like this:

However, elements emit/absorb light at very specific frequencies. This is unique to every element, meaning we can use it as an elemental fingerprint, identifying every element specifically!

Here’s carbon.

Now for how we discovered helium.

In 1868, two French astronomers observed during a solar eclipse (!) a spectrum that did not match any known element.

Remember, every absorption spectrum is unique to each element. This spectrum being unknown meant that this was a completely new, unique substance.

They named this new element helium, after the Greek god of the sun Helios!

And that’s how we discovered helium!