The Large Magellanic Cloud is the largest of the dozens of small satellite galaxies that orbit the Milky Way. The Tarantula Nebula is the largest and brightest star-forming region not just in the Large Magellanic Cloud, but in the entire group of nearby galaxies to which the Milky Way belongs.

The Tarantula Nebula is home to the most massive stars known, some of which are roughly 200 times as massive as our Sun. The scene pictured here is located away from the centre of the nebula, where there is a super star cluster called R136, but very close to a rare type of star called a Wolf-Rayet star. Wolf-Rayet stars are massive stars that have lost their outer shell of hydrogen and are extremely hot and luminous, powering dense and furious stellar winds.

This nebula is a frequent target for Hubble, whose multiwavelength capabilities are critical for capturing sculptural details in the nebula’s dusty clouds. The data used to create this image come from an observing program called Scylla, named for a multi-headed sea monster from the Greek myth of Ulysses. The Scylla program was designed to complement another Hubble observing program called ULLYSSES (Ultraviolet Legacy Library of Young Stars as Essential Standards). ULLYSSES targets massive young stars in the Small and Large Magellanic Clouds, while Scylla investigates the structures of gas and dust that surround these stars.

NASA’s Lunar Trailblazer ended its mission to the Moon on July 31. Despite extensive efforts, mission operators were unable to establish two-way communications after losing contact with the spacecraft the day following its Feb. 26 launch.

The mission aimed to produce high-resolution maps of water on the Moon’s surface and determine what form the water is in, how much is there, and how it changes over time. The maps would have supported future robotic and human exploration of the Moon as well as commercial interests while also contributing to the understanding of water cycles on airless bodies throughout the solar system.

Lunar Trailblazer shared a ride on the second Intuitive Machines robotic lunar lander mission, IM-2, which lifted off at 7:16 p.m. EST on Feb. 26 aboard a SpaceX Falcon 9 rocket from the agency’s Kennedy Space Center in Florida. The small satellite separated as planned from the rocket about 48 minutes after launch to begin its flight to the Moon. Mission operators at Caltech’s IPAC in Pasadena established communications with the small spacecraft at 8:13 p.m. EST. Contact was lost the next day.

Without two-way communications, the team was unable to fully diagnose the spacecraft or perform the thruster operations needed to keep Lunar Trailblazer on its flight path.

“At NASA, we undertake high-risk, high-reward missions like Lunar Trailblazer to find revolutionary ways of doing new science,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington. “While it was not the outcome we had hoped for, mission experiences like Lunar Trailblazer help us to learn and reduce the risk for future, low-cost small satellites to do innovative science as we prepare for a sustained human presence on the Moon. Thank you to the Lunar Trailblazer team for their dedication in working on and learning from this mission through to the end.”

The limited data the mission team had received from Lunar Trailblazer indicated that the spacecraft’s solar arrays were not properly oriented toward the Sun, which caused its batteries to become depleted.

For several months, collaborating organizations around the world — many of which volunteered their assistance — listened for the spacecraft’s radio signal and tracked its position. Ground radar and optical observations indicated that Lunar Trailblazer was in a slow spin as it headed farther into deep space.

“As Lunar Trailblazer drifted far beyond the Moon, our models showed that the solar panels might receive more sunlight, perhaps charging the spacecraft’s batteries to a point it could turn on its radio,” said Andrew Klesh, Lunar Trailblazer’s project systems engineer at NASA’s Jet Propulsion Laboratory in Southern California. “The global community’s support helped us better understand the spacecraft’s spin, pointing, and trajectory. In space exploration, collaboration is critical — this gave us the best chance to try to regain contact.”

However, as time passed, Lunar Trailblazer became too distant to recover as its telecommunications signals would have been too weak for the mission to receive telemetry and to command.

Technological Legacy

The small satellite’s High-resolution Volatiles and Minerals Moon Mapper (HVM3) imaging spectrometer was built by JPL to detect and map the locations of water and minerals. The mission’s Lunar Thermal Mapper (LTM) instrument was built by the University of Oxford in the United Kingdom and funded by the UK Space Agency to gather temperature data and determine the composition of silicate rocks and soils to improve understanding of why water content varies over time.

“We’re immensely disappointed that our spacecraft didn’t get to the Moon, but the two science instruments we developed, like the teams we brought together, are world class,” said Bethany Ehlmann, the mission’s principal investigator at Caltech. “This collective knowledge and the technology developed will cross-pollinate to other projects as the planetary science community continues work to better understand the Moon’s water.”

Some of that technology will live on in the JPL-built Ultra Compact Imaging Spectrometer for the Moon (UCIS-Moon) instrument that NASA recently selected for a future orbital flight opportunity. The instrument, which has has an identical spectrometer design as HVM3, will provide the Moon’s highest spatial resolution data of surface lunar water and minerals.

More About Lunar Trailblazer

Lunar Trailblazer was selected by NASA’s SIMPLEx (Small Innovative Missions for Planetary Exploration) competition, which provides opportunities for low-cost science spacecraft to ride-share with selected primary missions. To maintain the lower overall cost, SIMPLEx missions have a higher risk posture and less-stringent requirements for oversight and management. This higher risk acceptance bolsters NASA’s portfolio of targeted science missions designed to test pioneering mission approaches.

Caltech, which manages JPL for NASA, led Lunar Trailblazer’s science investigation, and Caltech’s IPAC led mission operations, which included planning, scheduling, and sequencing of all spacecraft activities. Along with managing Lunar Trailblazer, NASA JPL provided system engineering, mission assurance, the HVM3 instrument, and mission design and navigation. Lockheed Martin Space provided the spacecraft, integrated the flight system, and supported operations under contract with Caltech. The University of Oxford developed and provided the LTM instrument, funded by the UK Space Agency. Lunar Trailblazer, a project of NASA’s Lunar Discovery and Exploration Program, was managed by NASA’s Planetary Missions Program Office at Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.

Reporting in the Cell Press journal iScience, Bambi outlines the blueprint for turning this interstellar voyage to a black hole into a reality. If successful, this century-long mission could return data from nearby black holes that completely alter our understanding of general relativity and the rules of physics.

“We don’t have the technology now,” says author Cosimo Bambi of Fudan University in China. “But in 20 or 30 years, we might.”

The mission hinges on two key challenges — finding a black hole close enough to target and developing probes capable of withstanding the journey.

Previous knowledge on how stars evolve suggests that there could be a black hole lurking just 20 to 25 light-years from Earth, but finding it won’t be easy, says Bambi. Because black holes don’t emit or reflect light, they are virtually invisible to telescopes. Instead, scientists detect and study them based on how they influence nearby stars or distort light.

“There have been new techniques to discover black holes,” says Bambi. “I think it’s reasonable to expect we could find a nearby one within the next decade.”

Once the target is identified, the next hurdle is getting there. Traditional spacecrafts, powered by chemical fuel, are too clunky and slow to make the journey. Bambi points to nanocrafts — gram-scale probes consisting of a microchip and light sail — as a possible solution. Earth-based lasers would blast the sail with photons, accelerating the craft to a third of the speed of light.

At that pace, the craft could reach a black hole 20 to 25 light-years away in about 70 years. The data it gathers would take another two decades to get back to Earth, making the total mission duration around 80 to 100 years.

Once the craft is near the black hole, researchers could run experiments to answer some of the most pressing questions in physics. Does a black hole truly have an event horizon, the boundary beyond which not even light can escape its gravitational pull? Do the rules of physics change near a black hole? Does Einstein’s theory of general relativity hold under the universe’s most extreme conditions?

Bambi notes that the lasers alone would cost around one trillion euros today, and the technology to create a nanocraft does not yet exist. But in 30 years, he says that costs may fall and technology may catch up to these bold ideas.

“It may sound really crazy, and in a sense closer to science fiction,” says Bambi. “But people said we’d never detect gravitational waves because they’re too weak. We did — 100 years later. People thought we’d never observe the shadows of black holes. Now, 50 years later, we have images of two.”

This work was supported by funding from the National Natural Science Foundation of China.

The cosmic behemoth is close to the theoretical upper limit of what is possible in the universe and is 10,000 times heavier than the black hole at the center of our own Milky Way galaxy.

It exists in one of the most massive galaxies ever observed – the Cosmic Horseshoe – which is so big it distorts spacetime and warps the passing light of a background galaxy into a giant horseshoe-shaped Einstein ring.

Such is the enormousness of the ultramassive black hole’s size, it equates to 36 billion solar masses, according to a new paper published on August 7 in Monthly Notices of the Royal Astronomical Society.

It is thought that every galaxy in the universe has a supermassive black hole at its center and that bigger galaxies host bigger ones, known as ultramassive black holes.

“This is amongst the top 10 most massive black holes ever discovered, and quite possibly the most massive,” said researcher Professor Thomas Collett, of the University of Portsmouth.

“Most of the other black hole mass measurements are indirect and have quite large uncertainties, so we really don’t know for sure which is biggest. However, we’ve got much more certainty about the mass of this black hole thanks to our new method.”

Researchers detected the Cosmic Horseshoe black hole using a combination of gravitational lensing and stellar kinematics (the study of the motion of stars within galaxies and the speed and way they move around black holes).

The latter is seen as the gold standard for measuring black hole masses, but doesn’t really work outside of the very nearby universe because galaxies appear too small on the sky to resolve the region where a supermassive or ultramassive black hole lies.

Adding in gravitational lensing helped the team “push much further out into the universe,” Professor Collett said.

“We detected the effect of the black hole in two ways – it is altering the path that light takes as it travels past the black hole and it is causing the stars in the inner regions of its host galaxy to move extremely quickly (almost 400 km/s).

“By combining these two measurements we can be completely confident that the black hole is real.”

Lead researcher, PhD candidate Carlos Melo, of the Universidade Federal do Rio Grande do Sul (UFRGS) in Brazil, added: “This discovery was made for a ‘dormant’ black hole – one that isn’t actively accreting material at the time of observation.

“Its detection relied purely on its immense gravitational pull and the effect it has on its surroundings.

“What is particularly exciting is that this method allows us to detect and measure the mass of these hidden ultramassive black holes across the universe, even when they are completely silent.”

The Cosmic Horseshoe black hole is located a long way away from Earth, at a distance of some 5 billion light-years.

“Typically, for such remote systems, black hole mass measurements are only possible when the black hole is active,” Melo said. “But those accretion-based estimates often come with significant uncertainties.

“Our approach, combining strong lensing with stellar dynamics, offers a more direct and robust measurement, even for these distant systems.”

The discovery is significant because it will help astronomers understand the connection between supermassive black holes and their host galaxies.

“We think the size of both is intimately linked,” Professor Collett added, “because when galaxies grow they can funnel matter down onto the central black hole.

“Some of this matter grows the black hole but lots of it shines away in an incredibly bright source called a quasar. These quasars dump huge amounts of energy into their host galaxies, which stops gas clouds condensing into new stars.”

Our own galaxy, the Milky Way, hosts a 4 million solar mass black hole. Currently it’s not growing fast enough to blast out energy as a quasar but we know it has done in the past, and it may will do again in the future.

The Andromeda Galaxy and our Milky Way are moving together and are expected to merge in about 4.5 billion years, which is the most likely time for our supermassive black hole to become a quasar once again, the researchers say.

An interesting feature of the Cosmic Horseshoe system is that the host galaxy is a so-called fossil group.

Fossil groups are the end state of the most massive gravitationally bound structures in the universe, arising when they have collapsed down to a single extremely massive galaxy, with no bright companions.

“It is likely that all of the supermassive black holes that were originally in the companion galaxies have also now merged to form the ultramassive black hole that we have detected,” said Professor Collett.

“So we’re seeing the end state of galaxy formation and the end state of black hole formation.”

The discovery of the Cosmic Horseshoe black hole was somewhat of a serendipitous discovery. It came about as the researchers were studying the galaxy’s dark matter distribution in an attempt to learn more about the mysterious hypothetical substance.

Now that they’ve realized their new method works for black holes, they hope to use data from the European Space Agency’s Euclid space telescope to detect more supermassive black holes and their hosts to help understand how black holes stop galaxies forming stars.

Increasing the density and improving the spacing of seismic stations around the state could add 5 to 15 seconds to these estimated warning times, write Alexander Fozkos and Michael West at the University of Alaska Fairbanks. Alaska experiences tens of thousands of earthquakes each year, and has been the site some of the world’s largest and most destructive seismic events.

The study’s findings published in the Bulletin of the Seismological Society of America could help lay the groundwork for the expansion of the U.S. ShakeAlert earthquake early warning system, which now covers California, Oregon and Washington State.

“There were a lot of studies before EEW was widely available on the West Coast, where people were looking at different scenarios,” said Fozkos. “So we wanted a similar kind of science up here with numbers that are Alaska specific.”

For earthquakes along well-known faults in southcentral and southeast coastal Alaska, Fozkos and West estimated potential warning times of 10 to 120 seconds for magnitude 8.3 scenarios.

For magnitude 7.3 earthquake scenarios in crustal faults in interior and southcentral Alaska, the researchers estimated potential warning times ranging from 0 to 44 seconds.

And for a set of magnitude 7.8 earthquake scenarios along the dip of the subducting slab beneath Alaska, estimated warning times ranged from 0 to 73 seconds.

“I was expecting decent warning times along the coast and for most of the subduction zone events,” said Fozkos, because there is dense seismic station coverage in these areas. “I was not expecting decent warning times for the shallow crustal events, so that was the biggest surprise to me.”

The scenarios used in the study vary in earthquake magnitude, depth, location and fault style — all of which impacted warning times. The researchers’ models estimated how many seconds after an earthquake’s origin the quake could be detected, how many seconds after origin time an alert could be available, and minimum and maximum warning times at a location.

Warning times were defined as the time difference between the time of the alert and the time that peak ground motion from an earthquake arrived at a location. This definition differs from a more common definition used in EEW systems, which ties warning time to the arrival of the initial S-wave or shear wave of an earthquake.

The researchers wanted to use peak ground motion instead, to create a warning time measurement that might be more relevant to people as they respond to an earthquake. The initial S-wave may not always cause significant ground motion, and strong shaking can arrive tens of seconds after the initial S-wave in large earthquakes, they explain.

The study doesn’t analyze “the time it takes to disseminate the alert — the time it actually takes to send the alert from a radio tower or from a satellite to somebody’s phone and then for them to take out their phone and react to it,” Fozkos noted.

The potential lag time in transmitting data and sharing an alert with the public “could be a big challenge for Alaska, but I don’t think it’s going to be insurmountable,” he added.

The harsh Alaskan winters and wilderness locations of some seismic stations could also be challenging for an early warning system, if stations go down and can’t be repaired quickly. “I think there is definitely a need for adding stations to cover redundancy for remote stations,” Fozkos said.

Ocean-bottom seismometers (OBS) and more earthquake detection via distributed acoustic sensing or DAS would also be welcome additions to a warning system, he added. “Coupled with the fact that some of our biggest earthquakes are going to be offshore, tsunamigenic threats, I think OBS and DAS are probably big targets for the future.”