Origin of Supermassive Black Hole Flares Identified: Magnetic “Reconnection” Near the Event Horizon

By SIMONS FOUNDATION FEBRUARY 5, 2022

A top-down view of a black hole during the lead-up to a flare. Hot plasma initially flows into the black hole. As the magnetic field evolves, this flow reverses and launches some material outward. That accelerated material generates the flare. Credit: B. Ripperda et al., Astrophysical Journal Letters 202

Largest-ever simulations suggest flickering powered by magnetic ‘reconnection.’

Researchers at the Flatiron Institute and their collaborators found that breaking and reconnecting magnetic field lines near the event horizon release energy from a black hole’s magnetic field, accelerating particles that generate intense flares. The findings hint at exciting new possibilities in black hole observation.

Black holes aren’t always in the dark. Astronomers have spotted intense light shows shining from just outside the event horizon of supermassive black holes, including the one at our galaxy’s core. However, scientists couldn’t identify the cause of these flares beyond the suspected involvement of magnetic fields.

By employing computer simulations of unparalleled power and resolution, physicists say they’ve solved the mystery: Energy released near a black hole’s event horizon during the reconnection of magnetic field lines powers the flares, the researchers report in The Astrophysical Journal Letters.

The new simulations show that interactions between the magnetic field and material falling into the black hole’s maw cause the field to compress, flatten, break and reconnect. That process ultimately uses magnetic energy to slingshot hot plasma particles at near light speed into the black hole or out into space. Those particles can then directly radiate away some of their kinetic energy as photons and give nearby photons an energy boost. Those energetic photons make up the mysterious black hole flares.

A snapshot from one of the new black hole simulations. Credit: B. Ripperda et al., Astrophysical Journal Letters 2022

In this model, the disk of previously infalling material is ejected during flares, clearing the area around the event horizon. This tidying up could provide astronomers an unhindered view of the usually obscured processes happening just outside the event horizon.

“The fundamental process of reconnecting magnetic field lines near the event horizon can tap the magnetic energy of the black hole’s magnetosphere to power rapid and bright flares,” says study co-lead author Bart Ripperda, a joint postdoctoral fellow at the Flatiron Institute’s Center for Computational Astrophysics (CCA) in New York City and Princeton University. “This is really where we’re connecting plasma physics with astrophysics.”

Ripperda co-authored the new study with CCA associate research scientist Alexander Philippov, Harvard University scientists Matthew Liska and Koushik Chatterjee, University of Amsterdam scientists Gibwa Musoke and Sera Markoff, Northwestern University scientist Alexander Tchekhovskoy and University College London scientist Ziri Younsi.

A top-down view of a black hole during the lead-up to a flare. Hot plasma initially flows into the black hole. As the magnetic field evolves, this flow reverses and launches some material outward. That accelerated material generates the flare. Credit: B. Ripperda et al., Astrophysical Journal Letters 202

A black hole, true to its name, emits no light. So flares must originate from outside the black hole’s event horizon — the boundary where the black hole’s gravitational pull becomes so strong that not even light can escape. Orbiting and infalling material surrounds black holes in the form of an accretion disk, like the one around the behemoth black hole found in the M87 galaxy. This material cascades toward the event horizon near the black hole’s equator. At the north and south poles of some of these black holes, jets of particles shoot out into space at nearly the speed of light.

Identifying where the flares form in a black hole’s anatomy is incredibly difficult because of the physics involved. Black holes bend time and space and are surrounded by powerful magnetic fields, radiation fields and turbulent plasma — matter so hot that electrons detach from their atoms. Even with the help of powerful computers, previous efforts could only simulate black hole systems at resolutions too low to see the mechanism that powers the flares.

Ripperda and his colleagues went all in on boosting the level of detail in their simulations. They used computing time on three supercomputers — the Summit supercomputer at Oak Ridge National Laboratory in Tennessee, the Longhorn supercomputer at the University of Texas at Austin, and the Flatiron Institute’s Popeye supercomputer located at the University of California, San Diego. In total, the project took millions of computing hours. The result of all this computational muscle was by far the highest-resolution simulation of a black hole’s surroundings ever made, with over 1,000 times the resolution of previous efforts.

The increased resolution gave the researchers an unprecedented picture of the mechanisms leading to a black hole flare. The process centers on the black hole’s magnetic field, which has magnetic field lines that spring out from the black hole’s event horizon, forming the jet and connecting to the accretion disk. Previous simulations revealed that material flowing into the black hole’s equator drags magnetic field lines toward the event horizon. The dragged field lines begin stacking up near the event horizon, eventually pushing back and blocking the material flowing in.

A snapshot from one of the new black hole simulations. Here, green magnetic field lines are overlaid on a map of hot plasma. Just outside the black hole’s event horizon, the connection of magnetic field lines pointing in opposite directions makes an X-point where they crisscross. This process of reconnection launches some particles in the plasma into the black hole and others into space, an important step in the generation of black hole flares. Credit: B. Ripperda et al., Astrophysical Journal Letters 2022

With its exceptional resolution, the new simulation for the first time captured how the magnetic field at the border between the flowing material and the black hole’s jets intensifies, squeezing and flattening the equatorial field lines. Those field lines are now in alternating lanes pointing toward the black hole or away from it. When two lines pointing in opposite directions meet, they can break, reconnect and tangle. In between connection points, a pocket forms in the magnetic field. Those pockets are filled with hot plasma that either falls into the black hole or is accelerated out into space at tremendous speeds, thanks to energy taken from the magnetic field in the jets.

“Without the high resolution of our simulations, you couldn’t capture the subdynamics and the substructures,” Ripperda says. “In the low-resolution models, reconnection doesn’t occur, so there’s no mechanism that could accelerate particles.”

Plasma particles in the catapulted material immediately radiate some energy away as photons. The plasma particles can further dip into the energy range needed to give nearby photons an energy boost. Those photons, either passersby or the photons initially created by the launched plasma, make up the most energetic flares. The material itself ends up in a hot blob orbiting in the vicinity of the black hole. Such a blob has been spotted near the Milky Way’s supermassive black hole. “Magnetic reconnection powering such a hot spot is a smoking gun for explaining that observation,” Ripperda says.

The researchers also observed that after the black hole flares for a while, the magnetic field energy wanes, and the system resets. Then, over time, the process begins anew. This cyclical mechanism explains why black holes emit flares on set schedules ranging from every day (for our Milky Way’s supermassive black hole) to every few years (for M87 and other black holes).

Ripperda thinks that observations from the recently launched James Webb Space Telescope combined with those from the Event Horizon Telescope could confirm whether the process seen in the new simulations is happening and if it changes images of a black hole’s shadow. “We’ll have to see,” Ripperda says. For now, he and his colleagues are working to improve their simulations with even more detail.

Reference: “Black Hole Flares: Ejection of Accreted Magnetic Flux through 3D Plasmoid-mediated Reconnection” by B. Ripperda, M. Liska, K. Chatterjee, G. Musoke, A. A. Philippov, S. B. Markoff, A. Tchekhovskoy and Z. Younsi, 14 January 2022, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ac46a1

The Falcon 9 may now be the safest rocket ever launched

The Falcon 9 also recently surpassed the space shuttle in total flights.

ERIC BERGER - 2/3/2022, 9:06 AM

Enlarge / A Falcon 9 rocket launches on a pillar of fire in January 2022.
SpaceX

SpaceX has been launching Falcon 9 rockets thick and fast of late. With 10 launches since the beginning of December, the company has flown rockets at a rate greater than one mission a week. And another launch could happen as soon as today, shortly after noon (18:13 UTC), with a Starlink satellite launch planned from Florida.

Lost amid the flurry of activity are some pretty significant milestones for the Falcon 9 rocket, which made its debut a little more than a decade ago.
Number of launches

The Falcon 9 rocket has now launched a total of 139 times. Of those, one mission failed, the launch of an International Space Station supply mission for NASA, in June 2015. Not included in this launch tally is the pre-flight failure of a Falcon 9 rocket and its Amos-6 satellite during a static fire test in September 2016.

Since the year 2020, the Falcon 9 has been the most experienced, active rocket in the United States, when it surpassed the Atlas V rocket in total launches. Globally, the still-flying Russian Soyuz and Proton rockets have more experience than the Falcon 9 fleet. The Soyuz, of course, remains the king of all rockets. It has more than 1,900 launches across about a dozen variants of the booster dating back to 1957, with more than 100 failures.

The Falcon 9 reached a notable US milestone in January, equaling and then exceeding the tally of space shuttle launches. During its more than three decades in service, NASA's space shuttle launched 135 times, with 133 successes. To put the Falcon 9's flight rate into perspective, it surpassed the larger shuttle in flights in about one-third of the time.

There is no way to know how many missions the Falcon 9 will ultimately fly. At its current rate, the rocket could reach 500 flights before the end of this decade. However, SpaceX is also actively working to put its own booster out of business. The success of the company's Starship project will probably ultimately determine how long the Falcon 9 will remain a workhorse.

Nevertheless, it seems likely the Falcon 9 will fly for a long time yet. That is because it now provides the only means for US astronauts to get into space. And while NASA's deep-space Orion vehicle and Boeing's Starliner spacecraft should come online within the next couple of years, the Falcon 9 rocket and Crew Dragon spacecraft will very likely remain the lowest risk, and lowest cost, means of putting humans into orbit for at least the next decade.Advertisement

Consecutive successes

Speaking of safety, this is where the Falcon 9 rocket has really shone of late. Since the Amos-6 failure during its static fire test, SpaceX has completed a record-setting run of 111 successful Falcon 9 missions in a row. It probably will be 112 after Thursday.

There are only two other rockets with a string of successful flights comparable to the Falcon 9. One is the Soyuz-U variant of the Russian rocket, which launched 786 times from 1973 to 2017. The other is the American Delta II rocket, which recently retired. (Eventually, the Atlas V rocket could also exceed 100 consecutive successes before its retirement later this decade.)

According to Wikipedia, amid its long run, the Soyuz-U rocket had a streak of 112 consecutive successful launches between July 1990 and May 1996. However this period includes the Cosmos 2243 launch in April 1993. This mission should more properly be classified as a failure. According to noted space scientist Jonathan McDowell, the control system of the rocket failed during the final phase of the Blok-I burn, and the payload was auto-destructed.

Taking this failure into account, the Soyuz-U had a run of 100 successful launches from 1983 to 1986. This happens to be the exact same number of consecutive successes by the Delta II rocket, originally designed and built by McDonnell Douglas and later flown by Boeing and United Launch Alliance. Overall the Delta II rocket launched 155 times, with two failures. Its final flight, in 2018, was the rocket's 100th consecutive successful mission.

So the Falcon 9 has now exceeded both the Soyuz-U and Delta II rockets for consecutive mission successes, and apparently its low flight insurance costs reflect this.

What seems remarkable about all of this is that the Falcon 9 amassed this safety record at the very same time SpaceX was experimenting with and demonstrating reuse. At the time of the Amos-6 failure in 2016, the company had yet to re-fly a single Falcon 9 first stage. Now it has pushed some of its boosters to fly 11 flights, and SpaceX has never lost a mission on a reused first stage, even though founder Elon Musk and other officials have explicitly said they are pushing the technology to find its limits.

That would seem to be a fairly powerful argument in favor of the safety of reusable launch.

SpaceX Shares Breathtaking Video Of Rocket Separating At 5,984 Km/h!

By Ramish Zafar
Feb 6, 2022

The first stage of the SpaceX Falcon 9 standing tall after completing the COSMO SkyMed launch at the end of January. Image: SpaceX/Twitter

Space Exploration Technologies Corporation (SpaceX) has shared breathtaking footage of the company's Falcon 9 rocket. The footage is from SpaceX's recent launch for the Italian Space Agency, which saw the company launch the COSMO-SkyMed earth observation satellite. The footage marks a rare occasion where color and high-definition views of the Falcon 9's two separate stages separating were captured during flight, as SpaceX managed to land the first stage booster on land as opposed to on its traditional sea-based platforms.

SpaceX Video Shows Falcon 9 Separating In Mid-Air While Travelling Faster Than A Bullet

SpaceX is the only entity in the world, public or private, that is capable of landing the first stage rocket boosters of a medium-lift launch vehicle. According to the National Aeronautics and Space Administration (NASA), a medium-lift rocket is one that can carry 5 to 20 tons of payload to orbit, and the Falcon 9 is capable of delivering up to 22.8 tons to orbit according to its latest specifications.

Additionally, the Falcon 9 is also one of the cheapest rockets in the world, once it has been reflown a handful of times. This is due to the rocket being able to land its first-stage booster, which allows SpaceX to massively save up on the costs of building a rocket. In fact, statements made by the company's chief executive officer Mr. Elon Musk have suggested that the bulk of the costs for a Falcon 9 launch that reuses its first stage are those for the second or upper stage, which is incapable of landing.

The SpaceX Falcon 9 as it soars to the sky to deliver the Italian Space Agency's COSMO 

SkyMed satellite earlier this week. Image: SpaceX/YouTube

During the flight, the first stage is responsible for doing most of the work of pushing the rocket's payload out of the Earth's atmosphere. During this period, the Falcon 9 travels at least as fast as 5,000 kilometers per hour, and once its main engines shut off, the first stage detaches itself from the rocket to land back on Earth.

After detaching, and once it is safely away from the second stage, the first stage then reorients itself to make sure its engines are pointing towards its landing site. Following this, its Merlin engines reignite to slow down the half-rocket to ensure that it can successfully land.



The first (left) and second (right) stages of the Falcon 9 after separating during the COSMO

The second stage, visible at the right above, then ignites its Merlin vacuum engine to continue the remainder of the journey. This engine is also capable of shutting down and reigniting, and the number of times it does so depends on the trajectory of its payloads. Payloads with destinations higher in altitude often require more thrust before they can reach their destination.

SpaceX's latest video is a rare occasion where the entire sequence of events has been captured in color, providing us with a detailed peek into what occurs in the skies after the Falcons take off. Following the stage separation, pictured above, the Merlin engine on the second stage successfully ignited, and soon afterward, the payload fairings present on the second stage also successfully separated. The payload fairing is what is dubbed in the space industry as the 'shell' surrounding a payload, and both events are also clearly visible in the video

SpaceX Melts New Rocket Engine During Test Shows Fiery Video

The Cosmo SkyMed, short for 'COnstellation of small Satellites for the Mediterranean basin Observation', is an Earth observation satellite system funded by the Italian government and intended for both civilian and military use. It is built by the French-Italian aerospace manufacturer Thales Alenia Space, and each satellite weighs roughly four tons. SpaceX launched the second of the four satellites, with the previous one having taken to the skies on a Russian Soyuz rocket last year. The remaining two are planned to fly on the ISA and Ariannespace's Vega-C rocket.

You can take a look at the full footage from SpaceX below:

The author has no position in any of the stocks mentioned. WCCF TECH INC has a disclosure and ethics policy.

 

 SkyMed launch. Some of the white plumes are from the first stage's cold gas thrusters which fire at pre-determined times for reorientation before its primary engines reignite. Prior to this, the rocket was traveling at 5,984 km/h according to telemetry data from SpaceX's live stream. Image: SpaceX/YouTube

Cognitive Capitalism

Carlo Vercellone

Published 2008

9 Views25 Pages

2 Files ▾

Knowledge,

Division of Labour

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et a ̀ la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

‘ A starving mob has no respect’.

 Urban markets and food riots in the Roman world, 100 BC - AD 400

Paul Erdkamp

19 Pages

1 File ▾

Ancient History,

Roman History,

Food History,

Mobs, Riots, and Revolutionary Crowds                                                                                                                                             

Bakers and the Baking Trade in the Roman Empire: Social and Political Responses from the Principate to Late Antiquity

Harry Morgan

53 Pages

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Ancient History,

Cultural History,

Roman History,

Sociology of Work,

Social History,

Roman Economy,

Baking,

Bread History

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A baker’s funerary relief from Rome

     Published 2009

539 ViewsPaperRank: 4.824 Pages

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Rome, City of,

Roman Funerary Art

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This article presents a previously unpublished Roman travertine relief showing scenes of breadmaking, currently in the restaurant Romolo in Trastevere in Rome. It presumably came originally from a tomb monument, possibly in the vicinity, and might be dated on grounds of material and style anywhere between the very late Republic and the Flavian period. From left to right it shows two men delivering of sacks of grain, a man loading grain into an animal-driven mill, three men keading dough by hand, three more shaping loaves, and one putting loaves into the oven. The article discusses parallels in other reliefs of bakery scenes, and highlights the importance of this one for the evidence that it provides for the extent of division of labour in a fairly large-scale bakery. Despite points of comparison with other better-known bakery scenes, notably that from the tomb of Eurysaces, the narrative sequence is clearer and not directly paralleled, and the relief is the only one to show the manual kneading of dough. 

           

The First Fruits of God's Creatures: Bread, Eucharist, and the Ancient Economy

Andrew McGowan

2019, Full of Your Glory

260 ViewsPaperRank: 2.023 Pages

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Early Christianity,

Liturgical History,

Bread History

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Publication Date: 2019

Publication Name: Full of Your Glory                                                                                                                                                                          

 

Animal genomes: Chromosomes almost unchanged for over 600 million years

by University of Vienna

Credit: Pixabay/CC0 Public Domain

By comparing chromosomes of different animal groups scientists at the University of Vienna led by Oleg Simakov and at the University of California made an astonishing discovery: Every animal species has almost the same chromosomal units that appear over and over again—and this has been the case since the first animals emerged about 600 million years ago. Using new principles, human chromosomes can now also be dissected into these primordial "elements." The new study has just been published in the journal Science Advances.

Animal diversity is fascinating, but how is this reflected in their genetic material, the genome? Is it possible to definitely distinguish animals from one another based on genetic information, and perhaps even make predictions about how genetic information changes over time? This has been the great hope since the beginning of the "genome era" in 2000, when the human genome was sequenced for the first time. More than 20 years later, scientists now have access to technologies that can reveal the complete sequence of entire chromosomes that comprise the genome. Before, they could only study smaller fragments of chromosomes.

In their new study, the researchers compared chromosomes from different animal groups. Their conclusion: every animal species has almost the same chromosomal units. These chromosomal units, also called "elements," have remained constant in evolution, so that genomes of almost every animal can be represented exactly by listing the combinations of these basic building blocks.

Genomic diversity through mixing of these elements

Although these chromosomal elements remain constant during evolution, they can mix in different ways. The researchers succeeded in classifying these mixtures and deriving general principles that can be viewed as simple mathematical formulas. Until then, it was only possible to determine how many chromosomes an animal had, but not which ones exactly and their evolutionary history. "So now, for example, we can break down each human chromosome into its elements using algebraic notation. Then we deduce what happened to these primordial elements in different species and genera such as corals, molluscs, birds and many others, and what new chromosomes these elements had assembled into," explains molecular biologist Oleg Simakov from the University of Vienna.

Mixing of elements is irreversible

Another finding from the study: the individual chromosomal elements never return to their original, separate state once they have mixed together to form a new chromosome. "Such events are irreversible in evolution and every group of animals—from corals to humans—has such unique combinations that will forever distinguish the descendants of these groups and set these groups apart from others," Simakov said.

The researchers were also able to determine the origin of many animal chromosomal elements and show that the single-celled organisms most closely related to animals have only a few of these elements—many elements therefore only evolved in the very first animals. Why the chromosomal elements are so well conserved, what role the mixing of the elements might play in evolution and many other questions remain open and are still being researched.Unravelling the ancient stories hidden in DNA

More information: Oleg Simakov et al, Deeply conserved synteny and the evolution of metazoan chromosomes, Science Advances (2022). DOI: 10.1126/sciadv.abi5884. www.science.org/doi/10.1126/sciadv.abi5884

Journal information: Science Advances 

Provided by University of Vienna 

Martian Atmospheric Breakdown: Helicopters Flying on Mars May Glow at Dusk

By BILL STEIGERWALD, NASA GODDARD SPACE FLIGHT CENTER FEBRUARY 4, 2022

This is an artist’s concept of a glow surrounding a drone at Mars during flight. The glow, exaggerated for visibility, might happen if the drone’s spinning rotor blades generate an electric field that causes electric currents to flow in the Martian air around the craft. Although the currents generated by the drone in the atmosphere are small, they might be large enough to cause the air around the blades and other parts of the craft to glow a blue-purple color. Credit: NASA/Jay Friedlander

The whirling blades on drones flying above Mars may cause tiny electric currents to flow in the Martian atmosphere, according to a NASA study. These currents, if large enough, might cause the air surrounding the craft to glow. This process occurs naturally at much larger scales on Earth as a corona or electrical glow sometimes seen on aircraft and ships in electrical storms known as Saint Elmo’s Fire.

“The faint glow would be most visible during evening hours when the background sky is darker,” said William Farrell of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of a paper on this research published in Planetary Science Journal. “NASA’s experimental Ingenuity helicopter does not fly during this time, but future drones could be cleared for evening flight and look for this glow.”

“The electric currents generated by the fast-rotating blades on drones are too small to be a threat to the craft or the Martian environment, but they offer an opportunity to do some additional science to improve our understanding of an accumulation of electric charge called ‘triboelectric charging’,” added Farrell.

Triboelectric charging happens when friction transfers electric charge between objects, like when a person rubs a balloon against their hair or sweater. The electrified balloon will attract the person’s hair causing it to lift toward the balloon– which indicates that the balloon has developed a large electric field from the triboelectric charging process.

The team applied laboratory measurements and used computer modeling to investigate how electric charge could build up on a drone’s rotor blades. Charge buildup also happens on terrestrial helicopter blades, especially in dusty environments, so the team also used interpretations and modeling of the charging from terrestrial helicopters as a basis for understanding the Mars case.

They found that as the drone’s blades spin, they run into tiny dust grains in the Martian air, especially when the helicopter is near the surface and blowing dust around. As the blades impact the grains, charge is transferred, building up on the blades and creating an electric field. As charge builds to high levels, the atmosphere starts to conduct electricity, a process known as “atmospheric breakdown,” creating a population of electrons that form an enhanced electric current that acts to dissipate or offset the charge build-up on the rotorcraft.

The team found that breakdown begins as an invisible “electron avalanche.” Electrons are very small particles with negative electric charge. The charge makes electrons respond to electric fields – attracted to a field generated by positive charge and repelled from a field generated by negative charge. Free electrons – those not bound to an atom – in an electrically conducting material such as a copper wire are responsible for the flow of electric current. Atmospheres can have free electrons as well, and the few free electrons in the Martian air feel the force of the electric field from the rotorcraft and crash into atmospheric carbon dioxide (CO₂) molecules. The impact liberates more electrons from CO₂ molecules, which amplifies the current.

The Martian atmosphere is extremely thin, at the surface just about one percent of the pressure of Earth’s atmosphere at sea level. This very low pressure makes breakdown more likely. On Mars, the molecules that make up the atmosphere are spaced further apart than in an atmosphere like Earth’s, since they are less dense. Think of the electric field propelling the free electrons much like a car at the start of a drag race. If there are many large obstacles along the path, the accelerating car may hit them and slow down (or stop). The collisions limit the car’s speed to remain relatively slow. However, if the obstacles are very widely spaced, that same car will now accelerate to high velocities before hitting the obstacle. Similarly, the extra space in Martian air gives free electrons a greater path for acceleration before they ‘crash’ into a molecule, so they can reach the required velocity to kick off other electrons from the CO₂ molecules and start an electron avalanche within a relatively low electric field of around 30,000 volts per meter (1 meter is about 3.3 feet). On Earth, the same electron avalanche can occur, but in the denser atmosphere, the electric fields must be much larger, about 3,000,000 volts per meter.

Although the currents generated by a drone flying in the atmosphere are small, they might be large enough to cause the air around the blades and other parts of the craft to begin the electron avalanche and possibly even glow a blue-purple color.

However, the researchers acknowledge that their result is a prediction, and sometimes nature has other plans. “In theory, there should be some effect, but whether the electron avalanche is strong enough to create a glow, and if any weak glow is observable during operations all remain to be determined in future drone flights on Mars,” says Farrell “In fact, one could even place small electrometers up near the blade and at the legs to monitor the effects of any charging. This kind of electrical monitor could be of both scientific value and provide critical input on drone health during the flight.”

Reference: “Will the Mars Helicopter Induce Local Martian Atmospheric Breakdown?” by W. M. Farrell, J. L. McLain, J. R. Marshall and A. Wang, 10 March 2021, The Planetary Science Journal.
DOI: 10.3847/PSJ/abe1c3

The research was funded by NASA under the NASA Internal Science Funding Model and its Fundamental Laboratory Research (FLaRe) program, as well as a NASA grant funded under the Solar System Workings program.

This Is Real: NASA Camera – A Million Miles Away – Shows Moon Crossing Face of Earth

By COLIN KOVARIK FEBRUARY 5, 2022

This animation features actual satellite images of the far side of the moon, illuminated by the sun, as it crosses between the DSCOVR spacecraft’s Earth Polychromatic Imaging Camera (EPIC) and telescope, and the Earth – one million miles away. Credit: NASA/NOAA

Although it looks fake, this viral footage of the Moon orbiting Earth is actually real. It’s just not new, despite making the rounds again this week; it actually was captured over 6 years ago.

Back in 2015, a NASA camera aboard the Deep Space Climate Observatory (DSCOVR) captured this unique series of images displaying the ‘dark side’ of the moon. The ‘dark side’ of the moon is often used to refer to the hemisphere of the moon that is facing away from Earth. However, it is more properly called the ‘far side’ as it is exposed to an equal amount of sunlight as the side facing Earth. We can never view the ‘far side’ from Earth due to a phenomenon called tidal locking, which occurs when an astronomical body takes the same amount of time to complete a full rotation around its axis and fully orbit around its partner.

Although DSCOVR’s primary purpose is to monitor solar winds for the National Oceanic and Atmospheric Administration (NOAA), the satellite also houses NASA’s Earth Polychromatic Imaging Camera (EPIC) which captured these images. This four-megapixel CCD camera and telescope maintains a constant view of Earth as it orbits and takes 13-22 images every day.

In order to capture Earth’s ‘natural color’, NASA combines three different monochrome exposures taken 30 seconds apart. The final combined image has a slight green offset to the right of the moon and thin blue and red offsets to the left of it which is due to the Moon’s movement between each exposure.

If you wish to view more images taken by EPIC, NASA publishes daily color images of different views of the Earth as it rotates throughout the day.