Astronomers may have for the first time detected and measured the mass of an isolated stellar-mass black hole, a new study finds.
Previous research suggested that when giant stars more than 20 times the mass reach the end of their lives, they usually die in catastrophic explosions known as supernovas, and their dense cores are expected to collapse to become black holes.
Stars big enough to create black holes are estimated to make up about one out of a thousand stars, suggesting that in the Milky Way, “there should be about 100 million stellar-mass black holes,” study lead author Kailash Sahu, an astrophysicist at the Space Telescope Science Institute in Baltimore, told Space.com. (Stellar-mass black holes are up to a few times the sun‘s mass, as opposed to supermassive black holes millions of billions of solar masses large.)
Related: Where do black holes lead to?
Until now, all stellar-mass black holes detected to date have existed in binary systems with partners such as neutron stars. In contrast, the majority of the Milky Way’s stellar-mass black holes should be singletons, Sahu said.
However, “nobody has ever been able to find an isolated black hole,” Sahu said. As their name suggests, black holes absorb any light that falls into them, making them difficult to detect against the dark of space. Black holes are easier to detect in binary systems because their interactions with their partners can generate light or gravitational waves whose properties signal a black hole’s presence. In contrast, isolated black holes lack such partners to help reveal their existence.
Now, with the help of NASA’s Hubble Space Telescope, scientists have discovered an isolated stellar-mass black hole about 5,150 light-years away from Earth, in the direction of the bulge in the center of the Milky Way.
“We now know that isolated black holes exist,” Sahu said. “And they have masses similar to the black holes found in binaries. And there must be lots of them out there.”
The key behind this discovery is how powerful gravitational fields, such as those belonging to black holes, warp the fabric of space and time. As such, they can act like magnifying glasses, a phenomenon known as “gravitational lensing.”
“If one can detect and measure the bending of light caused by these massive objects, it’s possible to detect them and measure their masses,” Sahu said.
A number of ground-based survey programs monitor millions of stars every night to detect gravitational lensing events “where a star slowly brightens and fades over days or months,” Sahu said. “This microlensing phenomenon is caused by an intervening object, which can be a star or a white dwarf or a neutron star or a black hole or so on. The survey programs typically detect about 2,000 microlensing events per year. A small number of them are expected to be caused by black holes.”
The greater the mass of a gravitational lensing object, the longer the resulting brightening. Since a black hole is expected to be massive, its microlensing event is expected to have a long duration. “Also, a black hole is expected to be dark,” Sahu explained. “So we use these two as our main criteria — the event should have a long duration, and the lens should not be emitting any light.”
However, small-mass stars that move slowly in the sky may also look relatively dark and generate long-duration gravitational lensing events. One way to distinguish an isolated black hole from a small-mass star is the fact that a black hole will deflect the light from background stars “enough that it can be measured with Hubble,” Sahu said. “If the Hubble observations show large deflection but no light from the lens, then it would be a black hole.”
By combining Hubble observations with ground telescope data, the scientists discovered a 270-day-long microlensing event, called MOA-2011-BLG-191/OGLE-2011-BLG-0462, which they said likely came from an isolated black hole.
“It took two years of planning followed by six years of observing with Hubble, but it was very satisfying to see the incredible results,” Sahu said. “It was immediately clear as daylight that it’s a black hole, there was nothing else that could cause the deflections we measured.”
The researchers estimated this isolated black hole was about 7.1 times the mass of the sun. They also found this black hole is traveling at a speed of about 100,000 mph (162,000 kph). This suggested this black hole may have received a kick from the supernova explosion that gave birth to it.
The scientists detailed their findings online Jan. 31 in a study submitted to the Astrophysical Journal.
Originally published on Space.com.
James Webb Space Telescope's powers will be revealed in just weeks and scientists can't wait – Space.com
BALTIMORE — The James Webb Space Telescope’s first images are coming soon and scientists can’t wait for us to see them.
On Wednesday (June 29), NASA held a media day at the Space Telescope Science Institute (STScI) in Baltimore in advance of the release of the first science-quality images from the James Webb Space Telescope, which will occur during a live event on July 12. NASA scientists and administrators gave updates on the telescope, discussed Webb’s planned science during its first year in operation and hinted at the contents of some of Webb’s first official images.
“In a real sense, we’re sort of the first users of the observatory and using it for what it’s built for,” Klaus Pontoppidan, Webb project scientist at STScI, said during the news conference. “We recognize that we’re standing on the shoulders of all the scientists and engineers who’ve worked hard for the past six months to make this possible.”
Although NASA has already released a few images taken while aligning Webb, the images released on July 12 will be from a fully operational observatory, in full color, and they will show what each of the instruments on the telescope can contribute to science.
These first images will include a deep-field image peering farther into the past than ever before, scientists said during the briefing. NASA will also release Webb’s first spectroscopic data — precise data on the type of light that Webb detects that will allow scientists to learn more about the ingredients of distant cosmic objects. This data will include Webb’s first spectrum of an exoplanet, scientists said. While the images will be visually spectacular, the new information they reveal using Webb’s infrared-observing powers will distinguish them from images taken by other telescopes.
“The real difference is the new scientific information and then really opening up the longer wavelengths, infrared wavelengths in a way that we’ve really never seen before,” Jonathon Gardner, deputy senior project scientist for Webb, said during the news conference.
Each of the four instruments on Webb, including its main camera, two near-infrared spectrographs and a mid-infrared camera and spectrograph, will contribute to notable research in its first year of operation. They will collect data at nearly every scale and timescale, from our solar system today to the birth of our universe. Though scientists can detect radiation from near the beginning of our universe, no telescope has ever been able to detect light from some of the universe’s first stars and galaxies. Webb will be the first such observatory.
“The initial goal for this mission was to see the first stars and galaxies,” Eric Smith, Webb program scientist at NASA, said during the news conference. “Not the first light of the universe, but to watch the universe turn the lights on for the first time.”
Although Webb is already a remarkable feat, its first images represent the start of hopefully decades of science. Webb scientists said they have confirmed that the telescope has enough fuel to carry out science for the next 20 years. Data collected during these years could redefine how we understand our universe.
“This is really only the beginning,” Pontoppidan said. “We’re only scratching the surface.”
Astronauts Can Suffer a Decade of Bone Loss During Months in Space, New Research Suggests – Gizmodo
Long-term exposure to microgravity results in the loss of bone density, and new research reveals the disturbing extent to which this happens and finds that astronauts may never fully recover.
“The detrimental effect of spaceflight on skeletal tissue can be profound,” reads the opening sentence of new research published today in Scientific Reports. Profound is right. The study, led by kinesiologists Leigh Gabel and Steven Boyd from the University of Calgary, found that astronauts who participate in long-duration spaceflights (i.e. missions longer than three months) exhibit signs of incomplete bone recovery even after a full year back on Earth. Long-duration missions, it would seem, result in the premature aging of the bones, particularly bones in the weight-bearing lower extremities.
“We found that weight-bearing bones only partially recovered in most astronauts one year after spaceflight,” Gabel said in a statement. “This suggests the permanent bone loss due to spaceflight is about the same as a decade worth of age-related bone loss on Earth.”
The good news, if there is any in all of this, is that space-based resistance training can serve to limit the amount of bone loss and speed recovery. Previous research by the same team showed that “astronauts were more likely to preserve their bone density and strength if they increased in-flight lower body resistance training volume relative to preflight,” as the scientists write.
The new research shows how dependent we are on gravity for maintaining our bone strength. Each day is a constant struggle against gravity, but all this work does our body good, as it continually strengthens our bones. In space, however, astronauts just float around with barely any physical resistance, resulting in the gradual loss of bone density.
“Bone loss happens in humans—as we age, get injured, or any scenario where we can’t move the body, we lose bone,” Gabel said. “Understanding what happens to astronauts and how they recover is incredibly rare. It lets us look at the processes happening in the body in such a short time frame.”
The team traveled to NASA’s Johnson Space Center in Houston, Texas, to perform the study. In total, 17 international astronauts (14 men and three women) were studied, all of whom performed long-duration missions at some point during the past seven years. The astronauts were evaluated prior to their ISS spaceflights, and then six and 12 months after their return to Earth.
The team took bone scans of specific anatomical areas, namely the tibia, or shinbone, and the forearm. This allowed the scientists to measure the susceptibility of these bones to fracturing (or “failure load,” in the vernacular of kinesiologists), and the amount of bone mineral content and the thickness of bone tissue. They also recorded the astronauts’ workout routines during and after their space missions, including exercises such as deadlifts, running on a treadmill, and cycling.
Of the 17 astronauts studied, 16 exhibited incomplete recoveries of their shinbones (measures of their forearms didn’t really differ a year after the spaceflights). On average, the astronauts exhibited a tibia failure load capacity of 10,579 newtons prior to their spaceflights, but that dropped to 10,084 newtons upon their immediate return to Earth, for a loss of 495 newtons. The astronauts did manage to make a partial recovery in the year following their return, but they were still 152 newtons below their preflight tibia failure load values.
Their bone densities also took a beating. The astronauts had bone densities averaging 326 milligrams per cubic centimeter prior to their time in space, but this dropped to 282.5 mg per cubic centimeter upon their return—a drop of 43.5 mg per cubic centimeter.
“Our findings indicate that microgravity induces irreversible damage to bone strength, density, and trabecular bone microarchitecture,” the scientists wrote in their study. The trabecular bone is a “highly porous form of bone tissue that is organized into a network of interconnected rods and plates,” the function of which is to provide strength and channel external loads away from joints, according to unrelated research.
Unsurprisingly, the bone measures worsened depending on the length of the mission. The eight astronauts who were on the ISS for longer than six months recovered significantly less than those who participated in shorter missions, according to the study. At the same time, the astronauts who recovered the most tibia bone mineral density performed the most in-flight deadlift exercises.
“Since cramped quarters will be a limiting factor on future exploration-class missions, exercise equipment will need to be optimized for a smaller footprint,” the scientists write. “Resistance exercise training (particularly deadlifts and other lower-body exercises) will remain a mainstay for mitigating bone loss; however, adding a jumping exercise to on-orbit regimens may further prevent bone loss and reduce daily exercise time.”
These are important findings, particularly as NASA, through its upcoming Artemis program, is wanting to build a sustainable and prolonged presence on and around the Moon. The new research also speaks to future crewed missions to Mars, which will likewise feature prolonged stays in space. In addition to muscle atrophy and the loss of bone strength, microgravity imposes detrimental affects on the heart, eyes, brain, spine, cells, and overall physical fitness. It’s vital that we learn about all the risks associated with spaceflight and the best ways to mitigate them.
2022-06-29 | NDAQ:RKLB | Press Release | Rocket Lab USA Inc. – Stockhouse
Rocket Lab USA, Inc. (Nasdaq: RKLB) (“Rocket Lab” or “the Company”), a leading launch and space systems company, today announced its Lunar Photon spacecraft has successfully completed the third of seven planned orbit raising maneuvers, bringing the CAPSTONE spacecraft closer to the Moon.
This press release features multimedia. View the full release here: https://www.businesswire.com/news/home/20220629005956/en/
The CAPSTONE satellite integrated onto Rocket Lab’s Lunar Photon spacecraft before launch on the Electron rocket. (Photo: Business Wire)
Owned and operated by Advanced Space on behalf of NASA, the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) CubeSat will be the first spacecraft to test the Near Rectilinear Halo Orbit (NRHO) around the Moon. This is the same orbit intended for NASA’s Gateway, a multipurpose Moon-orbiting station that will provide essential support for long-term astronaut lunar missions as part of the Artemis program.
The orbit raising maneuvers come after Rocket Lab successfully launched CAPSTONE to an initial parking orbit on June 28 with an Electron rocket from Launch Complex 1 in New Zealand. With Electron’s role in the mission now complete, Lunar Photon has taken over the reins, providing power, communications and in-space transportation to CAPSTONE for the next five-day mission phase.
Over these days, Lunar Photon’s HyperCurie engine will perform a series of orbit raising maneuvers by igniting periodically to increase Photon’s velocity, stretching its orbit into a prominent ellipse around Earth. Six days after launch, HyperCurie will ignite one final time, accelerating Photon Lunar to 24,500 mph (39,500 km/h) and setting it on a ballistic lunar transfer. Within 20 minutes of this final burn, Photon will release CAPSTONE into space for the first leg of the CubeSat’s solo flight. CAPSTONE’s journey to NRHO is expected to take around four months from this point. Assisted by the Sun’s gravity, CAPSTONE will reach a distance of 963,000 miles from Earth – more than three times the distance between Earth and the Moon – before being pulled back towards the Earth-Moon system.
Rocket Lab founder and CEO Peter Beck said the launch of the CAPSTONE mission was the culmination of two and a half years of work and it pushed the Electron launch vehicle to the limit. “Electron lifted its heaviest payload yet at 300 kg – the combined mass of Lunar Photon and CAPSTONE. We pushed the Rutherford engines harder than we ever have before and deployed Lunar Photon and CAPSTONE exactly where they needed to go to begin the next mission phase. Now it’s Lunar Photon’s show and we’re immensely proud of its performance so far. We’re really pushing the boundaries of what’s possible for interplanetary smallsat missions with CAPSTONE and it’s exciting to think about the possibilities it opens up for more cost-effective missions to Mars, Venus and beyond.”
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+ About Rocket Lab
Founded in 2006, Rocket Lab is an end-to-end space company with an established track record of mission success. We deliver reliable launch services, satellite manufacture, spacecraft components, and on-orbit management solutions that make it faster, easier and more affordable to access space. Headquartered in Long Beach, California, Rocket Lab designs and manufactures the Electron small orbital launch vehicle and the Photon satellite platform and is developing the Neutron 8-ton payload class launch vehicle. Since its first orbital launch in January 2018, Rocket Lab’s Electron launch vehicle has become the second most frequently launched U.S. rocket annually and has delivered 147 satellites to orbit for private and public sector organizations, enabling operations in national security, scientific research, space debris mitigation, Earth observation, climate monitoring, and communications. Rocket Lab’s Photon spacecraft platform has been selected to support NASA missions to the Moon and Mars, as well as the first private commercial mission to Venus. Rocket Lab has three launch pads at two launch sites, including two launch pads at a private orbital launch site located in New Zealand and a second launch site in Virginia, USA which is expected to become operational in 2022. To learn more, visit www.rocketlabusa.com.
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