The Earth sets from the far side of the moon just beyond the Orion spacecraft in this video taken on the sixth day of the Artemis I mission.NASA
NASA’s Orion spaceship is hurtling around the moon for the first time, in the Artemis I mission.
Photos from the spacecraft show it leaving Earth and speeding to the far side of the moon.
It’s the first time a spacecraft made for humans has flown to the moon since the Apollo program ended 50 years ago.
NASA’s new Orion spaceship is beyond the far side of the moon, and it’s beaming gorgeous photos back to Earth.
The space capsule launched aboard the Space Launch System (SLS) rocket on November 15. Both the capsule and the rocket are designed to send humans back to the moon for the first time since the last Apollo mission in 1972 — reviving NASA’s moon ambitions in a new program called Artemis. Both the capsule and the rocket were flying for the first time.
The rocket’s job is done, but Orion is now completing a 25-day journey around the moon and back. The mission is called Artemis I. It’s a test flight to ensure the spacecraft can safely carry astronauts.
As Orion zipped away from Earth, its camera turned back to look at our planet.
One of Orion’s four solar arrays deploys shortly after launch, high above Earth.NASA
Orion entered the “lunar sphere of influence” on Sunday, where the moon overtakes Earth as the primary gravitational force.
The Orion spacecraft with the moon beyond was captured by a camera on the tip of one of Orion’s solar arrays.NASA
Then it skimmed past the moon on Monday, flying about 81 miles above the lunar surface, passing over three Apollo landing sites. The spaceship screamed past at about 5,102 miles per hour, then slowed to careen through space at 3,489 mph, according to NASA.
A portion of the far side of the Moon looms large the day Orion makes its close approach.NASA
Now Orion is on the far side of the moon. No humans have experienced this view firsthand since the Apollo missions. But if Orion succeeds on its first flight, NASA plans to send it with astronauts next time.
On Friday, Orion is set to reach its furthest point from the moon, about 57,287 miles past it.
Then on Monday, the spaceship should reach its farthest point from Earth, about 20,000 miles farther than any spacecraft made to transport humans has ever traveled.
This mission is designed to test the spaceship’s limits. Orion is carrying three mannequins fitted with scientific instruments and sensors, to measure the acceleration, vibration, and radiation that could impact future passengers.
The inside of the Orion crew module on flight day one of the Artemis I mission, with a “Moonikin” mannequin in the commander’s seat.NASA
The moon’s gravity should catapult Orion back toward Earth, hurtling the spaceship into a fiery fall through the atmosphere, which will test its heat shield’s capacity to protect passengers. Then Orion should release its parachutes and drift to a splashdown in the Pacific Ocean.
An artist’s illustration of the Orion capsule reentering Earth’s atmosphere and plummeting toward splashdown.NASA/Liam Yanulis
NASA plans to use SLS, Orion, and SpaceX’s Starship to land astronauts on the moon again in 2025. Eventually, the agency plans to set up a permanent base on the lunar surface and build a new space station in lunar orbit.
In May, the Event Horizon Telescope Collaboration shocked the world when it released an image of what appears to be a splotchy French cruller on fire. In reality, this wasn’t a doughnut. It was a stunning portrait of Sagittarius A*, the mighty black hole anchoring our galaxy, its gravitational pull silently brushing every star, planet and asteroid within.
This marked the first time we ever laid eyes on her majesty — a tremendous moment in its own right — but scientists weren’t done yet. There was far more to learn from Sgr A*.
From Earth’s vantage point, about 27,000 light-years away from this black hole, astronomers have been vigilantly watching and studying the void in an attempt to decode how, exactly, the Milky Way’s mighty engine works. And last month, a crew working with a powerful radio telescope called the Atacama Large Millimeter/submillimeter Array Observatory gleaned some novel clues.
After checking out ALMA data recorded in tandem with EHT observations of Sgr A*, during the black hole’s monumental imaging procedure, the team spotted what it calls a “hot spot” flitting around the abyss. This spot, they say, seems to be dimming and brightening while traveling clockwise around Sgr A*.
“We think we’re looking at a hot bubble of gas zipping around Sagittarius A* on an orbit similar in size to that of the planet Mercury, but making a full loop in just around 70 minutes,” Maciek Wielgus, of the Max Planck Institute for Radio Astronomy in Germany and lead author of the study published in Astronomy & Astrophysics, said in a statement.
For context, it takes Mercury 88 Earth days to make one orbit around the sun — and, at nearly 29 miles per second, this egg-shaped orb is considered the fastest planet.
So strikingly, for the hot ball of gas to totally make its way around Sgr A* in a mere 70 minutes, Wielgus said, “this requires a mind blowing velocity of about 30% of the speed of light.”
Plus, the researchers believe the bubble’s orbit sits at a distance from the void that’s about five times larger than what’s known as the black hole’s event horizon. Basically, there’s a barrier around every black hole beyond which light can’t escape. It signifies the firm boundary between our visible universe and whatever lies inside the beast. That’s the event horizon.
What’s the story with this bubble?
The study scientists think their newly located hot spot, according to the European Southern Observatory, is associated with bursts, or flares, of X-ray energy emitted from the Milky Way’s center. In fact, such flares have been detected in the past through both X-ray and infrared observations of Sagittarius A*, but this is the first time anyone has discovered them through radio telescope data — and with a “very strong indication” at that.
Possibly, the reason we’re seeing this energetic activity at varying wavelengths — X-ray, infrared and radio — is that their properties are changing over time.
“Perhaps these hot spots detected at infrared wavelengths are a manifestation of the same physical phenomenon: as infrared-emitting hot spots cool down, they become visible at longer wavelengths, like the ones observed by ALMA and the EHT,” Jesse Vos, a Ph.D. student at Radboud University in the Netherlands and co-author of the study, said in a statement.
This visible light, wide-field view shows rich star clouds in the constellation of Sagittarius. It’s pointed in the direction of the center of our Milky Way galaxy.
ESO and Digitized Sky Survey 2. Acknowledgment: Davide De Martin and S. Guisard
Further, findings of the team’s new study also appear to be in line with another long-theorized hypothesis: that flares spit from the Milky Way’s center are rooted in magnetic interactions stemming from hot gas swirling near Sgr A*.
“Now we find strong evidence for a magnetic origin of these flares and our observations give us a clue about the geometry of the process. The new data are extremely helpful for building a theoretical interpretation of these events,” Monika Mościbrodzka, of Radboud University and co-author of the study, said in a statement.
Those interpretations, the team explains, could include a peek into the black hole’s elusive magnetic field as a whole, or insight into the environment around the strange hot spot. Ultimately, perhaps they could paint a picture of what really is going on at the heart of the Milky Way — the quietly chaotic place where a monstrous black hole takes residence.
“In the future we should be able to track hot spots across frequencies using coordinated multi-wavelength observations with both GRAVITY and ALMA,” Ivan Marti-Vidal, of the University of Valencia in Spain and co-author of the study, said in a statement, referring to another of ESO’s astronomy instruments.
“The success of such an endeavor would be a true milestone for our understanding of the physics of flares in the Galactic center.”
Astronomers have spotted signs of a ‘hot spot’ orbiting Sagittarius A*, the black hole at the center of our galaxy.
Astronomers have spotted signs of a ‘hot spot’ orbiting Sagittarius A*, the
This shows a still image of the supermassive black hole Sagittarius A*, as seen by the Event Horizon Collaboration (EHT), with an artist’s illustration indicating where the modeling of the ALMA data predicts the hot spot to be and its orbit around the black hole. Credit: EHT Collaboration, ESO/M. Kornmesser (Acknowledgment: M. Wielgus)
The observations were made with ALMA in the Chilean Andes, during a campaign by the Event Horizon Telescope (EHT) Collaboration to image black holes. ALMA is — a radio telescope co-owned by the European Southern Observatory (ESO). In April 2017 the EHT linked together eight existing radio telescopes worldwide, including ALMA, resulting in the recently released first-ever image of Sagittarius A*. To calibrate the EHT data, Wielgus and his colleagues, who are members of the EHT Collaboration, used ALMA data recorded simultaneously with the EHT observations of Sagittarius A*. To the research team’s surprise, there were more clues to the nature of the black hole hidden in the ALMA-only measurements.
Using ALMA, astronomers have found a hot bubble of gas that swirls around Sagittarius A*, the black hole at the center of our galaxy, at 30% of the speed of light.
By chance, some of the observations were done shortly after a burst or flare of X-ray energy was emitted from the center of our galaxy, which was spotted by This video shows an animation of a hot spot, a bubble of hot gas, in orbit around Sagittarius A*, a black hole four million times more massive than our Sun that resides at the center of our
Credit: EHT Collaboration, ESO/L. Calçada (Acknowledgment: M. Wielgus)
“Perhaps these hot spots detected at infrared wavelengths are a manifestation of the same physical phenomenon: as infrared-emitting hot spots cool down, they become visible at longer wavelengths, like the ones observed by ALMA and the EHT,” adds Jesse Vos. He is a PhD student at Radboud University, the Netherlands, and was also involved in this study.
The flares were long thought to originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A*, and the new findings support this idea. “Now we find strong evidence for a magnetic origin of these flares and our observations give us a clue about the geometry of the process. The new data are extremely helpful for building a theoretical interpretation of these events,” says co-author Monika Moscibrodzka from Radboud University.
This is the first image of Sgr A*, the supermassive black hole at the center of our galaxy. It’s the first direct visual evidence of the presence of this black hole. It was captured by the Event Horizon Telescope (EHT), an array that linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. The telescope is named after the event horizon, the boundary of the black hole beyond which no light can escape. Credit: EHT Collaboration
ALMA allows astronomers to study polarized radio emission from Sagittarius A*, which can be used to unveil the black hole’s magnetic field. The team used these observations together with theoretical models to learn more about the formation of the hot spot and the environment it is embedded in, including the magnetic field around Sagittarius A*. Their research provides stronger constraints on the shape of this magnetic field than previous observations, helping astronomers uncover the nature of our black hole and its surroundings.
This image shows the Atacama Large Millimeter/submillimeter Array (ALMA) looking up at the Milky Way as well as the location of Sagittarius A*, the supermassive black hole at our galactic center. Highlighted in the box is the image of Sagittarius A* taken by the Event Horizon Telescope (EHT) Collaboration. Located in the Atacama Desert in Chile, ALMA is the most sensitive of all the observatories in the EHT array, and ESO is a co-owner of ALMA on behalf of its European Member States. Credit: ESO/José Francisco Salgado (josefrancisco.org), EHT Collaboration
The observations confirm some of the previous discoveries made by the GRAVITY instrument at ESO’s
Wide-field view of the center of the Milky Way. This visible light wide-field view shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the center of our Milky Way galaxy. The entire image is filled with vast numbers of stars — but far more remain hidden behind clouds of dust and are only revealed in infrared images. This view was created from photographs in red and blue light and forming part of the Digitized Sky Survey 2. The field of view is approximately 3.5 degrees x 3.6 degrees. Credit: ESO and Digitized Sky Survey 2. Acknowledgment: Davide De Martin and S. Guisard (www.eso.org/~sguisard)
The team is also hoping to be able to directly observe the orbiting gas clumps with the EHT, to probe ever closer to the black hole and learn more about it. “Hopefully, one day, we will be comfortable saying that we ‘know’ what is going on in Sagittarius A*,” Wielgus concludes.
More information
Reference: “Orbital motion near Sagittarius A* – Constraints from polarimetric ALMA observations” by M. Wielgus, M. Moscibrodzka, J. Vos, Z. Gelles, I. Martí-Vidal, J. Farah, N. Marchili, C. Goddi and H. Messias, 22 September 2022, Astronomy & Astrophysics. DOI: 10.1051/0004-6361/202244493
The team is composed of M. Wielgus (Max-Planck-Institut für Radioastronomie, Germany [MPIfR]; Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Poland; Black Hole Initiative at Harvard University, USA [BHI]), M. Moscibrodzka (Department of Astrophysics, Radboud University, The Netherlands [Radboud]), J. Vos (Radboud), Z. Gelles (Center for Astrophysics | Harvard & Smithsonian, USA and BHI), I. Martí-Vidal (Universitat de València, Spain), J. Farah (Las Cumbres Observatory, USA; University of California, Santa Barbara, USA), N. Marchili (Italian ALMA Regional Centre, INAF-Istituto di Radioastronomia, Italy and MPIfR), C. Goddi (Dipartimento di Fisica, Università degli Studi di Cagliari, Italy and Universidade de São Paulo, Brazil), and H. Messias (Joint ALMA Observatory, Chile).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning, and operation of ALMA.
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration in astronomy. Established as an intergovernmental organization in 1962, today ESO is supported by 16 Member States (Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland, and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor center and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvelous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal, and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates APEX and ALMA on Chajnantor, two facilities that observe the skies in the millimeter and submillimeter range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.
Astronomers have spotted signs of a ‘hot spot’ orbiting Sagittarius A*, the black hole at the center of our galaxy.
Astronomers have spotted signs of a ‘hot spot’ orbiting Sagittarius A*, the
This shows a still image of the supermassive black hole Sagittarius A*, as seen by the Event Horizon Collaboration (EHT), with an artist’s illustration indicating where the modeling of the ALMA data predicts the hot spot to be and its orbit around the black hole. Credit: EHT Collaboration, ESO/M. Kornmesser (Acknowledgment: M. Wielgus)
The observations were made with ALMA in the Chilean Andes, during a campaign by the Event Horizon Telescope (EHT) Collaboration to image black holes. ALMA is — a radio telescope co-owned by the European Southern Observatory (ESO). In April 2017 the EHT linked together eight existing radio telescopes worldwide, including ALMA, resulting in the recently released first-ever image of Sagittarius A*. To calibrate the EHT data, Wielgus and his colleagues, who are members of the EHT Collaboration, used ALMA data recorded simultaneously with the EHT observations of Sagittarius A*. To the research team’s surprise, there were more clues to the nature of the black hole hidden in the ALMA-only measurements.
Using ALMA, astronomers have found a hot bubble of gas that swirls around Sagittarius A*, the black hole at the center of our galaxy, at 30% of the speed of light.
By chance, some of the observations were done shortly after a burst or flare of X-ray energy was emitted from the center of our galaxy, which was spotted by This video shows an animation of a hot spot, a bubble of hot gas, in orbit around Sagittarius A*, a black hole four million times more massive than our Sun that resides at the center of our
Credit: EHT Collaboration, ESO/L. Calçada (Acknowledgment: M. Wielgus)
“Perhaps these hot spots detected at infrared wavelengths are a manifestation of the same physical phenomenon: as infrared-emitting hot spots cool down, they become visible at longer wavelengths, like the ones observed by ALMA and the EHT,” adds Jesse Vos. He is a PhD student at Radboud University, the Netherlands, and was also involved in this study.
The flares were long thought to originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A*, and the new findings support this idea. “Now we find strong evidence for a magnetic origin of these flares and our observations give us a clue about the geometry of the process. The new data are extremely helpful for building a theoretical interpretation of these events,” says co-author Monika Moscibrodzka from Radboud University.
This is the first image of Sgr A*, the supermassive black hole at the center of our galaxy. It’s the first direct visual evidence of the presence of this black hole. It was captured by the Event Horizon Telescope (EHT), an array that linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. The telescope is named after the event horizon, the boundary of the black hole beyond which no light can escape. Credit: EHT Collaboration
ALMA allows astronomers to study polarized radio emission from Sagittarius A*, which can be used to unveil the black hole’s magnetic field. The team used these observations together with theoretical models to learn more about the formation of the hot spot and the environment it is embedded in, including the magnetic field around Sagittarius A*. Their research provides stronger constraints on the shape of this magnetic field than previous observations, helping astronomers uncover the nature of our black hole and its surroundings.
This image shows the Atacama Large Millimeter/submillimeter Array (ALMA) looking up at the Milky Way as well as the location of Sagittarius A*, the supermassive black hole at our galactic center. Highlighted in the box is the image of Sagittarius A* taken by the Event Horizon Telescope (EHT) Collaboration. Located in the Atacama Desert in Chile, ALMA is the most sensitive of all the observatories in the EHT array, and ESO is a co-owner of ALMA on behalf of its European Member States. Credit: ESO/José Francisco Salgado (josefrancisco.org), EHT Collaboration
The observations confirm some of the previous discoveries made by the GRAVITY instrument at ESO’s
Wide-field view of the center of the Milky Way. This visible light wide-field view shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the center of our Milky Way galaxy. The entire image is filled with vast numbers of stars — but far more remain hidden behind clouds of dust and are only revealed in infrared images. This view was created from photographs in red and blue light and forming part of the Digitized Sky Survey 2. The field of view is approximately 3.5 degrees x 3.6 degrees. Credit: ESO and Digitized Sky Survey 2. Acknowledgment: Davide De Martin and S. Guisard (www.eso.org/~sguisard)
The team is also hoping to be able to directly observe the orbiting gas clumps with the EHT, to probe ever closer to the black hole and learn more about it. “Hopefully, one day, we will be comfortable saying that we ‘know’ what is going on in Sagittarius A*,” Wielgus concludes.
More information
Reference: “Orbital motion near Sagittarius A* – Constraints from polarimetric ALMA observations” by M. Wielgus, M. Moscibrodzka, J. Vos, Z. Gelles, I. Martí-Vidal, J. Farah, N. Marchili, C. Goddi and H. Messias, 22 September 2022, Astronomy & Astrophysics. DOI: 10.1051/0004-6361/202244493
The team is composed of M. Wielgus (Max-Planck-Institut für Radioastronomie, Germany [MPIfR]; Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Poland; Black Hole Initiative at Harvard University, USA [BHI]), M. Moscibrodzka (Department of Astrophysics, Radboud University, The Netherlands [Radboud]), J. Vos (Radboud), Z. Gelles (Center for Astrophysics | Harvard & Smithsonian, USA and BHI), I. Martí-Vidal (Universitat de València, Spain), J. Farah (Las Cumbres Observatory, USA; University of California, Santa Barbara, USA), N. Marchili (Italian ALMA Regional Centre, INAF-Istituto di Radioastronomia, Italy and MPIfR), C. Goddi (Dipartimento di Fisica, Università degli Studi di Cagliari, Italy and Universidade de São Paulo, Brazil), and H. Messias (Joint ALMA Observatory, Chile).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning, and operation of ALMA.
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration in astronomy. Established as an intergovernmental organization in 1962, today ESO is supported by 16 Member States (Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland, and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor center and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvelous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal, and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates APEX and ALMA on Chajnantor, two facilities that observe the skies in the millimeter and submillimeter range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.
An underwater volcano erupted in January near the Pacific nation of Tonga and sent massive pressure waves racing through Earth’s atmosphere, where they lapped the planet several times. The last volcano to generate such large ripples in the atmosphere was Krakatau in 1883, during one of the most destructive volcanic eruptions in recorded history, a new study shows.
“This atmospheric wave event was unprecedented in the modern geophysical record,” said first author Robin Matoza, an associate professor in the Department of Earth Science at the University of California, Santa Barbara. The research, published Thursday (May 12) in the journal Science, revealed that the pressure pulse generated by the Tonga volcano was “comparable in amplitude to that of the 1883 Krakatau eruption and over an order of magnitude greater than that of the 1980 Mount St. Helens eruption,” Matoza told Live Science in an email. The higher the amplitude of a wave, the more powerful it is.
A second study, also published May 12 in Science, suggested that this powerful pulse not only jiggled the atmosphere, but it also sent ripples racing across the ocean below. In fact, the atmospheric waves generated small, fast-traveling meteotsunamis — meaning series of waves driven by air-pressure disturbances — which reached the shore hours before the conventional, seismically-driven tsunamis generated by the volcano’s blast.
These small “forerunner” tsunamis were observed all around the world, primarily in the Pacific Ocean, but also in the Atlantic Ocean and Mediterranean Sea, surprisingly, said Tatsuya Kubota, a research fellow at the National Research Institute for Earth Science and Disaster Resilience in Japan and first author of the second study. “The height of the ‘forerunner’ tsunamis … was approximately a few centimeters or so, although it depends on the location,” Kubota told Live Science in an email.
Related: Dramatic photos show horrific aftermath of massive Tonga eruption and tsunami
An extremely energetic eruption
The Tonga volcano — called Hunga Tonga-Hunga Ha’apai, or just Hunga — lies about 40 miles (65 kilometers) northwest of the Tongan capital of Nuku’alofa. It’s one of 12 known underwater volcanoes in the Tonga-Kermadec volcanic arc, a geological structure that runs along the western edge of the Pacific plate of the Earth‘s crust, according to the Smithsonian’s Global Volcanism Program.
When Hunga erupted in mid-January, the resulting plume of gas and particles hit the mesosphere — the third layer of the atmosphere above Earth’s surface — making it the largest volcanic plume in the satellite record. The amount of energy released in the eruption was comparable to what might be generated by 4 to 18 megatons of TNT exploding, or more than 100 Hiroshima-scale bombs detonating at once.
Following the record-shattering eruption, Matoza and a team of more than 70 scientists from 17 nations set out to document what atmospheric waves were generated by the blast. To do so, they pulled data from numerous ground-based and spaceborne monitoring systems that had recorded the eruption as it unfolded.
The team found that, of all the atmospheric waves produced by the blast, so-called Lamb waves stood out as most prominent. Lamb waves run along the surface of the Earth and are similar to sound waves in that they produce vibrations in the medium they’re traveling through. However, Lamb waves propagate at extremely low frequencies, “where the effects of gravity become significant,” Matoza said.
These stereoscopic images show the Jan. 15 Hunga eruption from above. (Image credit: NASA Earth Observatory images and video by Joshua Stevens, using data courtesy of Kristopher Bedka and Konstantin Khlopenkov/NASA Langley Research Center, and GOES-17 imagery courtesy of NOAA and the National Environmental Satellite, Data, and Information Service (NESDIS))
Researchers rarely record Lamb waves, because they only arise from enormous explosions in the atmosphere, on the scale of large volcanic eruptions and nuclear tests. “They are not usually observed for smaller volcanic eruptions,” Matoza told Live Science.
Related: 4-foot tsunami hits Tonga after explosive eruption of underwater volcano
At their tallest, the Lamb waves generated by the Hunga eruption had an amplitude of 280 miles (450 km), meaning they hit the ionosphere — a dense layer of electrically charged particles that lies about 35 to 620 miles (60 to 1,000 km) above the planet’s surface. Over the course of six days, these waves radiated outwards from the volcano site, circling the Earth four times in one direction and three times in the other. Based on historical data, the 1883 Krakatau eruption generated Lamb waves that circled the Earth the same number of times, the researchers reported.
The team’s Lamb wave observations align with earlier models of the Hunga eruption event that were produced by Nedjeljka Žagar, a professor of theoretical meteorology at University of Hamburg, and her colleagues. “We were able to simulate the Hunga Tonga Lamb wave just two days after the event,” and now, the new Science study has provided more detail as to how these waves propagated, using various geophysical measurements, Žagar told Live Science in an email.
In their own Science study, Kubota and his colleagues connected the dots between these Lamb waves and the speediest tsunamis observed after the eruption. The timing of the Lamb waves and “forerunner” tsunamis seemed to coincide, they found. What’s striking is that these forerunner waves landed ashore more than two hours earlier than would be expected for conventional tsunamis, which are largely driven by sudden deformations in the seafloor.
In addition to huge Lamb waves and fast-moving tsunamis, the Hunga eruption also produced incredibly long-range sound waves and infrasound waves — meaning acoustic waves too low in frequency to be heard by humans, Matoza and his colleagues reported. The prominent Lamb waves led the pack, followed by the infrasound waves and then the audible sound waves. Remarkably, audible sounds, consisting of short, repeated “booms,” were reported all across Alaska, more than 6,200 miles (10,000 km) from the Hunga eruption.
An asteroid the size of the Eiffel Tower will zip past Earth Friday (March 5) and be out of our planetary neighborhood until 2029.
The space rock, dubbed Apophis (an ancient Egyptian demon), was first spotted in 2004 and won’t pose any danger to Earth during this week’s flyby; it will travel past the planet at more than 40 times the distance from Earth to the moon.
But scientists are using this week as a dress rehearsal for the asteroid’s next pass, on April 13, 2029, when Apophis will get as close to Earth as some of the highest-orbit satellites.
Related: Top 10 ways to destroy Earth
“Apophis in 2029 is going to be a really incredible observing opportunity for us,” Marina Brozović, a radar scientist at NASA’s Jet Propulsion Laboratory in California, told Live Science’s sister site Space.com. “But before we get to 2029, we are preparing.”
A brief flyby
Apophis is 1,120 feet (340-meter-wide) wide and made of rock, iron, and nickel. It is probably shaped roughly like a peanut, though astronomers will have a better idea of its form when it passes by Earth this week, according to NASA.
The asteroid takes a full orbit around the sun about every 11 months. On March 5, it will come within 10,471,577 miles (16,852,369 km) of Earth at 8:15 pm EST (0115 GMT on March 6).
That’s too far to be seen with the naked eye, but scientists will use planetary radar to image Apophis as it flies by using NASA’s Goldstone Deep Space Communications Complex in California and the Green Bank Telescope in West Virginia. They hope to determine the asteroid’s shape and learn more about the way it rotates.
“We know Apophis is in a very complicated spin state, it’s sort of spinning and tumbling at the same time,” Richard Binzel, a planetary scientist at the Massachusetts Institute of Technology, told Space.com.
Getting closer
This planetary radar study will provide researchers with a baseline for the much closer fly-by in 2029, when Apophis will get as close as 19,800 miles (31,900 kilometers) to Earth.
That’s close enough that Earth’s gravity might change the shape of the asteroid or scatter the boulders on its surface. How and if the asteroid changes as it flies by will help reveal details about the asteroid’s inner structure, Binzel said.
At its closest approach in 2029, Apophis will be briefly visible to the naked eye over western Australia, growing as bright as the stars in the Big Dipper.
It will be closest to Earth at 6 pm EDT on April 13, 2029, when it will be over the Atlantic – an ocean it will cross in only an hour. The asteroid will cross over the United States by 7 pm EDT.
Apophis is named after an ancient Egyptian demon who personified chaos and evil, largely because astronomers initially calculated that there was a 3 percent chance the asteroid could impact Earth on its 2029 flyby.
They’ve now shown that the asteroid won’t collide with Earth in 2029, nor on its next pass in 2036.
There’s still a slight chance that the asteroid could hit Earth in 2068, but the 2021 and 2029 flybys should give astronomers more information with which to calculate Apophis’ future.
Editor’s Note (6 March 2020): This article has been updated to correct how close Apophis will get to Earth during its flyby.
This article was originally published by Live Science. Read the original article here.
