This artist’s illustration imagines the view from the surface of one of the planets in the TRAPPIST-1 planetary system. Astronomers think that some of the planets in this system may have a substantial ocean of water, a necessary ingredient for life.
Credit: NASA/JPL-Caltech

One of the most stunning astronomical discoveries of the last decade was an entire system of exoplanets, relatively close to Earth, that have the potential to host life. During a Dec. 13, 2022 conference, astronomers reported preliminary findings about the system gathered by the powerful new James Webb Space Telescope (JWST).  

This artist’s illustration shows what the TRAPPIST-1 planetary system may look like. The planetary system has seven planets that rapidly orbit close to the parent star. Three of the planets orbit within the habitable zone of the star where liquid water can exist on a planet’s surface.
Credit: NASA/JPL-Caltech

TRAPPIST-1 is a red dwarf star about 40 light-years from Earth in the constellation Aquarius. One light-year equals the distance light travels in a vacuum in a year, about 5.88 trillion miles (9.46 trillion kilometers). TRAPPIST-1 is notable for having seven orbiting planets. Astronomers classify the planets as terrestrial, meaning they have Earthlike qualities. All of them orbit the star within or near a region that astronomers call the habitable zone. That is, in that region in which liquid water can exist on a planet’s surface. Scientists consider liquid water to be an essential ingredient for life. 

The first three planets in the TRAPPIST-1 system were discovered in 2015. These were discovered by astronomers using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) robotic telescope pair, located at La Silla Observatory in Chile and Oukaïmeden Observatory in Morocco. Scientists using the Spitzer Space Telescope and the Very Large Telescope in Chile announced in 2017 that they had confirmed the discovery of those three planets and had discovered four more planets. 

The potential of these planets to host conditions favorable for life made the TRAPPIST-1 system a major target for the JWST. This advanced satellite observatory was launched in December of 2021 and began conducting scientific observations in mid-2022. Earlier that year, JWST characterized the atmosphere of the giant exoplanet WASP-96b as a proof-of-concept, setting the stage for TRAPPIST-1 observations.  

The preliminary results from two of the TRAPPIST-1 planets confirm that they do not have hydrogen atmospheres. They may have no atmospheres, or they may have atmospheres composed of other gases, including carbon dioxide, methane, and water vapor. Such atmospheres could make these planets hospitable for life. 

Because these exoplanets are so small, even the powerful JWST needs to view the system for extended periods to gather accurate data. But the system’s diminutive proportions will speed up the observation process. JWST detects minute changes to the star’s light as each planet passes in front of it. The seven planets whirl around TRAPPIST-1 with orbital periods of 1.5 to 18.8 Earth days. In contrast, Earth’s orbital period (also called a year) is about 365 days, and Mercury’s is 88 Earth days. (Because TRAPPIST-1 is a small, cool star, these tight orbits still lie within or near its habitable zone.) Astronomers are confident that they will have a good “family portrait” of the TRAPPIST-1 within a year.  

JWST has already racked up impressive observations after just a half-year of activity. With its study of TRAPPIST-1, it will help bring astronomers closer to answering one of the most fundamental questions in science: are we living things on Earth alone in the universe, or not? 

John McFall, from the United Kingdom, is a member of the ESA Astronaut Class of 2022. John McFall is one of the more than 22 500 candidates who submitted a valid application in 2021 in response to ESA’s call for new astronauts for missions to the International Space Station and beyond. ESA’s new class of astronauts includes career astronauts, members for the astronaut reserve and astronauts with a physical disability for a feasibility project. They will start a 12-month basic training at ESA’s European Astronaut Centre in spring 2023.
Credit: P. Sebirot/ESA

The European Space Agency (ESA), a cooperative space program among the nations of Europe, made history in November 2022, naming the world’s first physically disabled astronaut. Paralympian and orthopedic surgeon John McFall joined 15 others out of 22,500 applicants in the journey to space. McFall had his right leg amputated after a motorcycle accident when he was 19 years old. Before his accident, he was a runner. McFall persevered through recovery and made it to the 2008 Paralympic Games in Beijing, China. He secured the bronze medal in the 100-meter race.

McFall was born on April 25, 1981, in Frimley, England. He was a runner before his accident in 2000. Determined to reach his goals despite his new existence as an amputee, McFall worked through recovery all the way to the Paralympics. He became a professional runner in 2005, only five years after his accident. After his success as a Paralympian, McFall trained as an orthopedic surgeon.

He studied at Swansea University in Wales 2004. He continued his education to earn his master’s degree at the University of Wales Institute in Cardiff in 2005. Not one to shy away from challenges and education, McFall graduated from Cardiff University School of Medicine in 2014. He joined the Royal College of Surgeons in 2016 and works as a trauma and orthopedic specialist in the south of England.

McFall heard that the ESA was looking to hire a Paralympian as an astronaut in February 2021 as he worked in the intensive therapy unit helping patients recover from COVID-19. He started filling out an application and soon was undergoing memory and physical tests and answering difficult questions in interviews.

The ESA named McFall and 15 others as official recruits in November 2022. The group will undergo more testing to ensure their ability to fulfill the role. McFall will take part in the Parastronaut Feasibility Project which will help the ESA understand how space flight works for astronauts with physical disabilities.

A hidden star catalog on an ancient manuscript attributed to Hipparchus
Credit: Early Manuscripts Electronic Library/Lazarus Project, University of Rochester

Scholars studying Biblical texts have made an almost unimaginable find—fragments of a lost star catalog compiled by the ancient astronomer Hipparchus. Hipparchus’s work represents the earliest known project to catalog the entire night sky. The find is an example of a palimpsest—a manuscript that has been written over with other writings. The discovery was announced in the fall of 2022. 

The lost fragments were discovered by researchers examining a text taken from the library of St. Catherine’s Monastery, a Greek Orthodox monastery on the Sinai peninsula in Egypt. That text was written during the Middle Ages, a period of history that lasted form about the 400’s through the 1400’s. 

The text was written not on paper, but on a specially prepared animal skin called parchment. However, parchment and other materials could be rare in the Middle Ages. For this reason, scribes sometimes scraped the surface of the parchment, clearing the page for a new manuscript. In many cases, the scraped away writing can still be detected, forming a type of hidden manuscript called a palimpsest. 

In 2012, a biblical scholar asked his college students to study the text beneath the manuscript, hoping to find earlier Christian writings. But one student spotted an astronomical passage often attributed to the ancient Greek mathematician Eratosthenes. 

In 2017, researchers at the University of Rochester in New York analyzed the pages using multi-spectral imaging. They took 42 photos of each page at various wavelengths of light. A computer algorithm then combined the various images to search for hidden markings. The researchers discovered myths about the stars’ origins compiled by Eratosthenes, along with a poem about the constellations. 

During the COVID-19 pandemic, the house-bound scholar passed the time re-examining the images. He was surprised to find what appeared to be stellar coordinates, numbers that can be used to measure the position of a star in the night sky.  

Using radiocarbon dating, the coordinates were determined to be written in the 400’s or 500’s A.D. However, the way they were written suggested that they might have been copied from Hipparchus. Moreover, astronomers know that the stars appear to change position over time due to a wobble in Earth’s axis, an effect called precession. The coordinates were so detailed that scholars could thus determine that they were taken in 129 B.C., during Hipparchus’s life. 

The oldest surviving star catalog comes from a work called the Almagest by the astronomer Ptolemy, compiled in the 100’s A.D. Hipparchus’s earlier catalog is mentioned in ancient sources. But with no surviving evidence, it was thought to be lost forever or even never to have existed. 

The new discovery sheds an amazing light on Hipparchus’s work. Compiled nearly 2,000 years before the invention of the telescope, his catalog would have required countless hours of measurement with a sighting tube or a device called an armillary sphere. For now, only a few fragments remain, but scientists hope that they will help to identify other fragments of Hipparchus’s work in other manuscripts. 

The Mariner 4 probe was launched in 1964 and traveled toward Mars. It was the first satellite to take up close pictures of another planet.
Credit: NASA

On Earth, the blue and green planet of our solar system, we are celebrating Red Planet Day today, November 28. The red planet is a nickname for Mars, the fourth planet from the sun. On November 28, 1964, NASA launched the first mission toward Mars, with the Mariner 4 probe. We call it “the Red Planet” because the surface of Mars has a reddish color due to the weathered iron-rich minerals present in the Martian dust and surface rocks. The iron oxidizes creating rust. We should call it the rusty planet! Many ancient peoples associated the planet with war and conflict because of its blood-red appearance. Indeed, Mars is the Latin name for the ancient Roman god of war.

Mars, like Earth, has clouds in its atmosphere and deposits of ice at its poles. But unlike Earth, Mars has little to no liquid water on its surface. The rustlike color of Mars comes from the large amount of iron in the planet’s soil.
Credit: NASA/JPL/Malin Space Science Systems

Humans have been studying Mars for centuries. Visible from Earth with the unaided eye, Mars has always captivated us! Of all the planets in our solar system, Mars has the surface environment that most closely resembles that of Earth. Mars has weather and seasons and landforms that appear familiar. Salty water may flow just below the planet’s surface. Like Earth, the sun, and the rest of the solar system, Mars is about 4.6 billion years old.

Mars has a special place in popular culture, one that is unique among the planets. This fascination with Mars probably developed because the planet is relatively close to and similar to Earth. Early observations with Earth-based telescopes inspired popular speculation that Mars was home to all kinds of life, even alien civilizations. Many works of science fiction have played upon these ideas, showing humans visiting Mars or malevolent Martians invading Earth.

A Martian landscape includes jagged rocks, sand dunes, and hazy clouds. The image, taken by the United States rover Curiosity, has been adjusted to show the natural color of the planet, as it would appear to an observer on the surface.
Credit: NASA/JPL-Caltech/MSSS

In the 1960’s, the U.S. Mariner spacecraft showed Mars to be a cold, desert planet devoid of visible life. But Mars continues to fascinate people with hints of past surface water and the possibility that microscopic life once existed or still exists there. Experts also view Mars as the next likely target for human space exploration and perhaps even as a stepping stone to exploring the rest of the solar system.

Robotic spacecraft began detailed observation of Mars in the 1960′s. The United States launched to Mars the Mariner 4 probe in 1964 and Mariners 6 and 7 in 1969. The pictures they returned showed a barren surface, covered with craters like those on the moon. There was no sign of liquid water or life. The spacecraft observed few of the planet’s most interesting features because they happened to fly by only heavily cratered regions. But when Mariner 9 went into orbit around Mars in 1971, people’s view of Mars completely changed. Mariner 9 mapped about 80 percent of Mars and made the first discoveries of the planet’s canyons and volcanoes. It also found the first evidence for water, taking photographs of the outflow channels and valley networks.

The Artemis I Space Launch System (SLS) and Orion spacecraft at NASA’s Kennedy Space Center on June 14, 2022.
Credit: KSC/NASA

The National Aeronautics and Space Administration is one step closer to getting astronauts back on the moon after the Artemis-1 mission launch today, November 16th, 2022. Artemis-1 is the first mission in the three-ply plan to establish a better understanding of the moon en route to landing on Mars. The un-crewed Orion spacecraft will be launched from NASA’s Kennedy Space Center in Florida, on the Space Launch System rocket, NASA’s newest and most powerful rocket. The mission has been delayed due to Hurricane Ian and tropical storm Nicole.

The program is named after Artemis, the goddess of hunting and the moon in Greek mythology. Artemis was the twin of Apollo, the god of light. The Apollo program was NASA’s first mission to land on the moon. The Orion spacecraft is named after Orion, a handsome and energetic hunter in Greek mythology. He was a giant who could walk through the sea and on its surface. In one myth, Artemis set Orion in the sky as a constellation after his death. Orion the Hunter, is a brilliant constellation that includes two of the brightest stars in the sky.

The mission is set to send Orion beyond the moon, launching it into orbit around the moon, before returning to Earth. Orion will travel 1.3 million miles (2.1 million kilometers) over the course of 42 days while orbiting the moon. Orion’s return to Earth will be the fastest and hottest planned spacecraft return in history. It is expected to land in the Pacific Ocean near San Diego, California, on Oct. 10. The Orion spacecraft is planned to carry astronauts to the International Space Station and, eventually, to the moon and Mars. The craft is designed to sustain astronauts during a long mission into deep space and return them safely to Earth.

NASA’s Space Launch System (SLS) rocket and Orion spacecraft roll out to the Launch Complex on Aug. 16, 2022, ahead of the scheduled launch of the Artemis 1 mission on Aug. 29, 2022.

Although on this trip, Orion is heading into space without passengers. the Orion spacecraft has many advanced features to support an astronaut crew on an extended mission into space. These features include unique systems for propulsion and flight control. Astronauts will be carried in Orion’s Crew Exploration Vehicle (CEV). The CEV is equipped with advanced heat shields to withstand the temperatures generated by the high velocities required to launch the craft into deep space and to reenter Earth’s atmosphere upon return. Orion cannot make it to space on its own, it requires a push from a heavy-lift rocket. That is where the Space Launch System (SLS) helps out. The SLS uses solid-fuel rocket boosters to carry heavy loads into space. The SLS is the most powerful rocket ever built for launching a space exploration vehicle. 

The first successful unpiloted test flight of the Orion spacecraft took place in 2014. The Orion CEV was launched on an older model Delta IV heavy rocket and orbited Earth twice before it splashed down and was recovered in the Pacific Ocean. A second test flight, in 2018, also used the Delta IV heavy rocket because of delays in the development of the SLS. Future unpiloted test flights are planned to test various components of the Orion spacecraft. Orion missions with astronauts are expected to take place later, in the 2020’s. The last manned mission to the moon was in 1972 when the Apollo 17 mission completed the longest lunar landing.

Nicole Aunapu Mann became the first Indigenous American woman in space in October 2022 aboard NASA’s SpaceX Crew-5 mission to the International Space Station.
Credit: NASA

Nicole Aunapu Mann is an American astronaut and Marine Corps test pilot. Today, October 5, 2022, Mann became the first Indigenous (native) American woman in space. Mann and three other astronauts launched on National Aeronautics and Space Administration’s (NASA) SpaceX Crew-5 mission to the International Space Station (ISS). While aboard the ISS, Mann will serve as a flight engineer. Mann is a member of the Wailacki people of the Round Valley Indian Tribes. The Round Valley Indian Tribes is a confederation of tribes designated to the Round Valley Indian Reservation in Mendocino County, California.

In 2013, the NASA chose Mann to be an astronaut. Mann completed astronaut training in July 2015. She led the development of the Exploration Ground Systems (EGS) launch facility, the Orion crewed spacecraft, and Space Launch System (SLS), built to carry the Orion craft into space. NASA selected Mann to serve as mission commander on NASA’s SpaceX Crew-5 mission on the Crew Dragon capsule en route to the International Space Station. SpaceX is a private company that owns and operates the rocket and spacecraft used in the mission. A Falcon 9 rocket was scheduled to launch the mission’s Crew Dragon capsule.

Mann joined the United States Marine Corps in 1999 as a second lieutenant. She reported to the Naval Air Station in Pensacola, Florida, for flight training in 2001. Mann became a Navy pilot in 2003 and began her operational flying career in 2004.  Mann deployed twice to Afghanistan and Iraq, completing 47 combat missions. After her deployments, she completed Navy Test Pilot School and served as a test pilot for many types of naval aircraft.

Nicole Victoria Aunapu was born in Petaluma, California, on June 27, 1977. She enrolled in the United States Naval Academy in Annapolis, Maryland, in 1995. Mann earned a bachelor’s degree in mechanical engineering in 1999. She completed a master’s degree in mechanical engineering from California’s Stanford University in 2001. In 2009, she married Navy pilot Travis Mann.

This illustration shows an imagined view of NASA’s Double Asteroid Redirection Test (DART) spacecraft approaching the asteroids Didymos and Dimorphos. The smaller spacecraft is LICIACube, built by the Italian Space Agency.
Credit: NASA/Johns Hopkins, APL/Steve Gribben

Scientists and engineers have designed spacecraft for many different purposes. Some bring people safely to the moon or the International Space Station. Others roam far into space to send pictures back to Earth for scientists to study. The National Aeronautics and Space Administration (NASA) built the Double Asteroid Redirection Test (DART) as a punching bag! DART was a spacecraft that intentionally collided with an asteroid.

Scientists planned the mission to find out whether a spacecraft collision could change an asteroid’s path through space. DART’s target asteroid was not a threat to Earth. But in the future, this method could be used to redirect a threatening asteroid away from Earth. Scientists are studying the effects of the DART impact to determine how the collision affected the asteroid’s path.

DART was a type of spacecraft called an impactor. An impactor smashes into the target it is studying, such as a planet, moon, or asteroid. Usually, scientists study the effects of the impact to learn about the physical characteristics of the target. Because DART was designed to move its target, it is considered a kinetic impactor.

DART traveled to Didymos, an asteroid that is about ½ mile (780 meters) wide. Didymos has a moonlet—a second, tiny asteroid in orbit around it—called Dimorphos. Dimorphos is sometimes nicknamed “Didymoon.” Dimorphos is 525 feet (160 meters) wide. Pairs of asteroids such as this one are known as binary systems. Scientists think about 15 percent of the asteroids closest to Earth are part of a binary system. Didymos and Dimorphos were chosen for the DART mission because their position is practical for a spacecraft to reach and because changes to Dimorphos’s orbit can be measured from Earth.

On Sep. 26, 2022, DART smashed into Dimorphos at a speed of 4.1 miles (6.6 kilometers) per second. Telescopes on Earth observed a bright flash at the moment of impact. Before the impact, Dimorphos orbited Didymos once every 11 hours and 55 minutes. The impact was expected to shorten this period and to move Dimorphos slightly closer to Didymos.

DART carried only one instrument, a camera. The camera helped it to steer automatically toward its target. DART also carried a shoebox-sized spacecraft called LICIACube. DART released LICIACube before it impacts Dimorphos. LICIACube photographed the impact test and its aftermath.

The National Aeronautics and Space Administration (NASA) launched DART on Nov. 24, 2021. The mission was sponsored by NASA’s Planetary Defense Coordination Office. The Italian Space Agency (ASI) built LICIACube. It is Italy’s first deep space probe.

Cuban cosmonaut Arnaldo Tamayo Méndez
Credit: Intercosmos

People in the United States observe National Hispanic Heritage Month each year from September 15 to October 15. During this period, Latin American countries celebrate their independence. These countries include Cuba, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, and Nicaragua.

Arnaldo Tamayo Méndez is a Cuban cosmonaut and politician. In Russia and the other former republics of the Soviet Union, astronauts are called cosmonauts. In 1980, Tamayo became the first Black person in space, when he spent a week docked at the Soviet Salyut 6 space station. That same year, he became a member of Cuba’s National Assembly.

Tamayo was born on Jan. 29, 1942, in Guantánamo. After being orphaned as a baby, he was raised by his maternal aunt and uncle. As a child, Tamayo worked many odd jobs, for example shining shoes, selling vegetables, and working as an apprentice carpenter.

After the Cuban dictator Fulgencio Batista fled the country in 1959, Tamayo joined the country’s Revolutionary Army (see Cuba (The Castro revolution). In 1961, he completed studies at the Technical Institute to be an aviation technician. He was then selected to continue studying in the Soviet Union. Tamayo learned how to pilot fighter jets at the Yeisk Higher Military Aviation School in Russia, on the Sea of Azov. He returned to Cuba in 1962 to become a flight instructor for the Cuban Revolutionary Guard. During the Cuban Missile Crisis of 1962, he participated in reconnaissance missions. He also served in the Vietnam War (1957-1975). By 1976, Tamayo had reached the rank of lieutenant colonel in the Cuban air force.

The Soviet Union selected Tamayo to participate in its Intercosmos program in 1978. The program was established to send non-Soviets into space on Soviet spacecraft. Tamayo spent two and a half years training at the Yuri Gargarin Soviet Space Center. On Sept. 18, 1980, Tamayo and the Soviet cosmonaut Yuri Romanenko blasted off on the Soyuz 38 mission. Tamayo became the first person from the Caribbean, the first Cuban, the first Latin American, and the first Black person in space. On the space station Salyut 6, the crew of Soyuz 38 joined other cosmonauts and carried out various experiments designed by Cuban scientists. The mission lasted a little over a week.

Tamayo and Romanenko were both awarded honors after landing. Tamayo became the first person ever awarded the Hero of the Republic of Cuba medal. Additionally, he received medals for Hero of the Soviet Union and the Order of Lenin. Tamayo continued his military service, eventually attaining the rank of brigadier general and serving as director of Cuba’s civil defense. His space suit is displayed in the Museum of The Revolution in Havana.

James Webb Space Telescope image of NGC 3324
Credit: NASA/ESA/CSA/STScI

The first images from the James Webb Space Telescope have arrived! They are starry, stellar, and dazzling images of never before seen nebulae and star-forming regions of the universe. The images are quite the upgrade from the images taken by the Hubble Space Telescope, showing deep space in exquisite detail. U.S. President Joe Biden released the first images on Monday, June 11, 2022.

The James Webb Space Telescope was successfully launched into space atop an Ariane 5 rocket on Dec. 25, 2021. The James Webb Space Telescope, abbreviated JWST, is an observatory replacing some capabilities of the Hubble Space Telescope. The Hubble Space Telescope is a powerful orbiting telescope that provides sharp images of heavenly bodies. Webb’s main mirror is 6.5 meters (21 feet) across. Webb will have about seven times larger light-collecting area than Hubble. However, Webb is designed to study infrared light, a type of light wave with longer wavelengths than those of visible light. Thus, Webb will not replace Hubble’s visible light capabilities.

Webb is a collaboration between the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Canadian Space Agency (CSA). The Space Telescope Science Institute, which currently operates Hubble, is managing Webb’s science operations. The telescope is named after James Webb, the former NASA administrator who conceived and directed the Apollo program for most of the 1960’s. Webb has been a work in progress since 1996 and its deployment was delayed many times over the years.

The Webb telescope will enable scientists to study the history of the universe, nearly all the way back to a cosmic explosion called the big bang. It will collect information on the first stars and galaxies that formed after the big bang, the formation of planetary systems, and the evolution of planets within the solar system.

Southern Ring Nebula
Credit: NASA/ESA/CSA/STScI

The first images NASA released show a star-forming region in the Milky Way called the Carina Nebula captured in infrared light. A nebula is a cloud of dust particles and gases in space. The term nebula comes from the Latin word for cloud. Other images show the Southern Ring Nebula in near-infrared light and mid-infrared light. This image shows the remains of a white dwarf star, similar to our Sun.

Webb is equipped with several specialized cameras and spectrometers, instruments that spread out light into a band of wavelengths called a spectrum. Astronomers can study such a spectrum for signs of light given off by certain molecules or atoms. Webb also has a primary (main) mirror made of many segments, which was folded up to fit in the launch rocket. The mirror is to unfold and adjust to its proper shape before Webb reaches its permanent orbit. A large sun shield, about the size of a tennis court, will help prevent the infrared light from the sun, and the reflected sunlight from Earth and the moon, from interfering with observations. Webb is specifically designed to cool down its sensors to gather better data.

After launch, Webb traveled to a Lagrange point, a special point in space where the gravitational pulls of the sun and Earth are in balance. Webb is to remain there, 930,000 miles (1.5 million kilometers) from Earth, observing the skies for up to 10 years. During its primary mission, Webb is designed to be the world’s premier space observatory, used by thousands of astronomers worldwide.

The first image of Sagittarius A*, the supermassive black hole at the center of our galaxy.
Credit: © EHT Collaboration

Finally, the faceless monster lurking at the center of our galaxy has been photographed. Sounds like science fiction? It’s true! On Thursday, May 12, scientists with the Event Horizon Telescope (EHT) team published a photograph of Sagittarius A* (saj uh TAIR eeuhs AY star). Sagittarius A* is a supermassive (huge) black hole in the center of our galaxy, the Milky Way.

A black hole is a region of space whose gravitational force is so strong that nothing can escape from it, not even light. The event horizon is the “point of no return” for a black hole: Anything that crosses this horizon is sucked into the black hole forever. Supermassive black holes at least a million times more massive than the sun lurk at the center of many galaxies.

The EHT is a global network of ground-based telescopes that use a technique called radio interferometry to produce images of black hole event horizons. The collection of radio telescopes participating in the EHT project stretches from Hawaii to Europe and all the way south to Antarctica. Several dozen of the world’s leading observatories and universities contribute to the project. Supercomputers process the image data using special algorithms in a process called correlation.

Astronomers began using the EHT to make observations of Sagittarius A* in 2017. In 2019, the EHT released an image it had captured of the event horizon surrounding the supermassive black hole at the center of the Messier 87 galaxy (M87*). It was the first time an event horizon had been photographed.

If light can’t escape a black hole, how did EHT photograph M87* or Sagittarius A*? Technically, it didn’t: all black holes are invisible and cannot be directly photographed. But matter trapped in orbit near the event horizon is extremely energized and emits large amounts of light. The black hole lurks in the circular “shadow” within the halo of high-energy matter. Thus, the EHT can take a picture of a black hole much as we can take a picture of a doughnut hole.

Despite being closer to Earth, Sagittarius A* was still harder to image than M87*. Sagittarius A* is still 27,000 light-years from Earth. It’s also more than 1,000 times smaller and less massive than M87*. So, although the high-energy matter is orbiting both black holes at about the same speed, the matter completes an orbit around Sagittarius A* in a matter of minutes. Furthermore, Sagittarius A* is “quieter”: it emits far less energy than M87*. All these factors made it difficult for EHT to capture an image of it.

Now that EHT has imaged two black holes, astronomers can compare them. Both look remarkably similar, despite their differing sizes. Both confirm what was predicted by Einstein’s theory of relativity. But plenty of questions remain. For example, are the “blobs” in the picture actual elements, or are they artifact of the correlating process? The EHT is also considering the feasibility of creating a short video of Sagittarius A* by stringing together multiple consecutive images. And plenty more supermassive black holes are waiting for their photographic debut. A major observation campaign that concluded earlier this year featured even more telescopes. Expect more exciting results soon regarding these most extreme objects in the universe.