Astronomy

Astrophysicist Priyamvada Natarajan predicted that black holes can form without the help of stars. New observations support her theory

A "damning" 2020 survey, conducted by the Royal Astronomical Society, reveals systemic bullying across the field of astronomy.

With liftoff now set for 29 May at 00:20 CEST (28 May, 15:20 local time), ESA’s EarthCARE satellite ready for launch at the Vandenberg Space Force Base in California. Once in orbit, this new satellite is set to revolutionise our understanding of how clouds and aerosols affect Earth’s climate.

ESA’s Solar Orbiter made the first ever connection between measurements of the solar wind around a spacecraft to high-resolution images of the Sun’s surface at a close distance. The success opens a new way for solar physicists to study the source regions of the solar wind.

ESA's EarthCARE mission is ready for lift-off! Follow the live coverage and launch today 28 May on ESA WebTV or ESA YouTube. Live coverage begins at 23:30 CEST where we'll hear from our mission scientists and spacecraft operators, then follow the launch on a SpaceX Falcon 9 from Vandenberg Space Force Base, California, expected at 00:20 CEST.

Normally you don’t want dust to get into your spacecraft. That was certainly true for the InSight mission to Mars, until it died. Now, however, it’s acting as a dust collector, and Mars Reconnaissance Orbiter (MRO) scientists couldn’t be happier.

The High Resolution Imaging Science Experiment (HiRISE) onboard MRO monitors and images the surface. In particular, it has been imaging landing sites on Mars to track dust accumulation on the surface. The idea is to see how quickly the landers and their nearby environments get covered. It doesn’t just focus on landing sites, though. It also checks places like impact craters to track surface changes in and around those regions. As you can see from its latest image above, taken on April 1st, 2024, it’s getting tough to spot the InSIGHT lander thanks to ever-growing accumulations of dust.

Monitoring Surface Changes on Mars

HiRISE has been checking in on the InSIGHT lander ever since it first deployed on Mars. Early images show the hardware in fairly good detail right after landing. Then, over time, as Martian winds take their toll, it’s obvious the spacecraft is getting coated in dust. That’s also true of other spacecraft that HiRISE images from time to time.

The best image of the InSight lander taken by HiRISE in 2019. HiRISE scientists were looking for dust devil tracks and other changes in the surface due to dust. Credit: NASA/JPL-Caltech/UArizona

Why care about dust? Although we know a great deal about Mars, there’s still a lot to figure out. Wind deposition of dust is part of the so-called aeolian processes that alter the Martian surface appearance. They’re named after the Greek wind god Aeolus. Dust storms are certainly visible on Mars from Earth, but we can’t really “see” their deposits easily without getting close to (or on) the planet. Other activities, such as dust devils, also redistribute dust around the planet. All this activity creates wind streaks, sand, and dust deposits, and covers up spacecraft on the surface.

The study of the aeolian process is one of the HiRISE instrument’s major science themes. There’s not much water action to change the surface. Nor is there any Martian volcanic activity to muck up the landscape. Impact craters do tear up the surface, but they aren’t frequent. That leaves aeolian activity as a major player in Mars surface changes. Image after image shows dunes, ripples, wind streaks, dust devil tracks, and other features created by the winds. The HiRISE imaging project gives a “wide-angle” view of aeolian effects on the Red Planet and how its various surface units change over time.

InSight’s Future on Mars

The InSight lander performed almost flawlessly during its four years in operation on Mars. Although one of its instruments, the “mole” had some difficulties performing its digging action, the mission as a whole was quite successful. The seismograph monitored Marsquakes throughout the mission, which gives details about the Martian interior. It also differentiated between quakes from Mars’s interior and those caused by impacts. The spacecraft other instruments sampled the remnants of the weak magnetic field and monitored the Martian weather.

The InSight lander not only measured seismic motions on Mars, but also sampled the atmosphere and listened to its winds. Courtesy: NASA/JPL.

As increasing levels of dust covered InSight’s solar panels, mission scientists had to power down many of its systems. The seismometer was the last one to be shut off. The spacecraft was officially considered “dead” after mission controllers didn’t hear from it after two attempts at communication. The last time anybody heard from it was December 15, 2022.

These days, although the instruments are silent and the solar panels are dead, the spacecraft is passively and rapidly accumulating dust. That gives scientists a chance to understand just how the surface changes thanks to aeolian activity.

For More Information

Revisiting InSight
Aeolian Themes for HiRISE
Winds of Mars
InSight Mission Ends

The post Mars InSight Has One Last Job: Getting Swallowed by Dust on the Red Planet appeared first on Universe Today.

Nothing lasts forever, including black holes. Over immensely long periods of time, they evaporate, as will other large objects in the Universe. This is because of Hawking Radiation, named after Stephen Hawking, who developed the idea in the 1970s.

The problem is Hawking Radiation has never been reliably observed.

A trio of European researchers think they’ve found a way to see Hawking Radiation. Their work is in a paper titled “Measuring Hawking Radiation from Black Hole Morsels in Astrophysical Black Hole Mergers.”

Black hole mergers were predicted long ago but never observed. Theory showed that these mergers should release powerful gravitational waves. Finally, in 2015, the LIGO observatory detected the first merger. Now, scientists have detected many of them.

In their brief research letter, the researchers say that these mergers are a window into Hawking Radiation (HR.) When black holes merge, they may create so-called “morsel” black holes the size of asteroids that are ejected into space. Their small size should make their HR detectable.

The HR coming from these small BHs produces gamma rays with a particular “fingerprint” of high-energy photons.

“In this letter, we explore the observational consequences of the production of a large number of small BH morsels during a catastrophic event such as the merger of two astrophysical BHs,” the authors explain. “As we shall show, the Hawking radiation stemming from these BH morsels gives rise to gamma-ray bursts (GRBs) possessing a distinctive fingerprint.”

When black hole morsels evaporate, they emit particles in a spherically symmetrical pattern. As long as the larger merged BH is not blocking their view, the HR particles should reach us. The photon energy from the bursts exceeds the trillion-electron volt (TeV) scale.

The researchers say that the energy level of the gamma-ray bursts from these morsel holes is detectable by atmospheric Cherenkov telescopes like the High-Altitude Water Cherenkov (HAWC) Gamma-ray observatory. HAWC observes photons in a range from 100 GeV to 100 TeV.

HAWC is at an altitude of 4100 meters ((2.5 miles) in Mexico. It’s one of several facilities that can detect energetic photons from morsel black holes. Image Credit: By Jordanagoodman – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=35122613

Many questions remain. The authors say that these morsel BHs will emit the most energy close to their time of evaporation. But when morsel BHs are emitted in the intense gravitational environment of a BH merger, their Hawking Radiation may be affected. The same is true if the morsels are emitted at relativistic velocities. Both of those factors could alter their spectra before they reach our detectors.

There are points in the Standard Model of Particle Physics where things break down due to our lack of understanding. The authors point out that some new physics not observed before could also distort the spectra from morsel black holes, making them tricky to observe.

There’s another really interesting aspect to these asteroid-size morsel black holes. Since the physics in the very early Universe were different, it’s possible they were created then. If they were, and if they haven’t evaporated by now, they could constitute dark matter.

“The observation of Hawking radiation from BH morsels, therefore, could enlighten us not only about the production of such morsels but also about particle physics at energies beyond the reach of current and future collider experiments, carrying imprints from new physics based on supersymmetry, composite dynamics, or extra dimensions, to name a few,” the authors write.

The post Merging Black Holes Could Give Astronomers a Way to Detect Hawking Radiation appeared first on Universe Today.

Image: Last look at EarthCARE

A single dose of genetically engineered immune cells reduced asthma symptoms in mice for at least a year

A single dose of genetically engineered immune cells reduced asthma symptoms in mice for at least a year

Observations made by the Magellan spacecraft in the 1990s include signs of recent lava flows, highlighting possible exploration targets for probes heading to Venus in the 2030s

Observations made by the Magellan spacecraft in the 1990s include signs of recent lava flows, highlighting possible exploration targets for probes heading to Venus in the 2030s

A new theory of quantum gravity, which attempts to unite quantum physics with Einstein's relativity, could help solve the puzzle of the universe's expansion, a theoretical paper suggests.

The evidence is in: Venus is volcanically active.

The post Venus’s Volcanoes Live appeared first on Sky & Telescope.

One way to explain why time only moves forward is the quantum arrow of time, and it has major implications for both the universe's early period and its eventual demise

One way to explain why time only moves forward is the quantum arrow of time, and it has major implications for both the universe's early period and its eventual demise

High school students in Russellville, Alabama win the American Rocketry Challenge after months of designing and building a victorious rocket.

A new official clip has just been released by Disney+ for "Star Wars: The Acolyte" showing off the martial arts fight choreography featured in the upcoming miniseries.

"Adoption of this alloy will lead to more sustainable aviation and space exploration."

SpaceX is set to launch yet another batch of its Starlink internet satellites from Florida on Tuesday morning (May 28).