(NASA) NASA's Mars Rover Opportunity catches its own late-afternoon shadow in this dramatically lit view eastward across Endeavour Crater on Mars.
The rover used the panoramic camera (Pancam) between about 4:30 and 5:00 p.m. local Mars time to record images taken through different filters and combined into this mosaic view.
Most of the component images were recorded during the 2,888th Martian day, or sol, of Opportunity's work on Mars (March 9, 2012). At that time, Opportunity was spending low-solar-energy weeks of the Martian winter at the Greeley Haven outcrop on the Cape York segment of Endeavour's western rim. In order to give the mosaic a rectangular aspect, some small parts of the edges of the mosaic and sky were filled in with parts of an image acquired earlier as part of a 360-degree panorama from the same location.
Opportunity has been studying the western rim of Endeavour Crater since arriving there in August 2011. This crater spans 14 miles (22 kilometers) in diameter, or about the same area as the city of Seattle. This is more than 20 times wider than Victoria Crater, the largest impact crater that Opportunity had previously examined. The interior basin of Endeavour is in the upper half of this view.
The mosaic combines about a dozen images taken through Pancam filters centered on wavelengths of 753 nanometers (near infrared), 535 nanometers (green) and 432 nanometers (violet). The view is presented in false color to make some differences between materials easier to see, such as the dark sandy ripples and dunes on the crater's distant floor.
Researchers at the IceCube Neutrino Observatory in Antarctica have discovered high-energy astrophysical neutrinos which are being produced in central parsec-scale regions of radio-bright active galaxies and quasars including 3C 279, NRAO 530, PKS 1741-038, and 4C +06.69. The first confirmed source of these high-energy cosmic neutrinos have eluded scientists for decades, but last September, that changed when such a particle struck a detector buried in ice at the South-Pole, research published in Science revealed. The event was coupled with the detection of a flaring ‘blazar’ by NASA’s Fermi Gamma-Ray Telescope giving us a clue as to the origin of these high-energy neutrinos. This discovery is not just significant for our knowledge of these particles however, it may help usher in a whole new age of ‘multi-messenger’ astronomy.
The IceCube Neutrino Observatory is the first detector of its kind, designed to observe the cosmos from deep within the South Pole ice. An international group of scientists responsible for the scientific research makes up the IceCube Collaboration. Encompassing a cubic kilometer of ice, IceCube searches for nearly massless subatomic particles called neutrinos. These high-energy astronomical messengers provide information to probe the most violent astrophysical sources: events like exploding stars, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars.
The Antarctic neutrino observatory, which also includes the surface array IceTop and the dense infill array DeepCore, was designed as a multipurpose experiment. IceCube collaborators address several big questions in physics, like the nature of dark matter and the properties of the neutrino itself. IceCube also observes cosmic rays that interact with the Earth’s atmosphere, which have revealed fascinating structures that are not presently understood.
The IceCube Lab at the South Pole in Antarctica. Image: S. Lidstrom/NSF
Approximately 300 physicists from 52 institutions in 12 countries make up the IceCube Collaboration. The international team is responsible for the scientific program, and many of the collaborators contributed to the design and construction of the detector. Exciting new research conducted by the collaboration is opening a new window for exploring our universe. The National Science Foundation (NSF) provided the primary funding for the IceCube Neutrino Observatory, with assistance from partner funding agencies around the world. The University of Wisconsin–Madison is the lead institution, responsible for the maintenance and operations of the detector. Funding Agencies in each collaborating country support their scientific research efforts.
Astronomers have observed that most star systems usually fall into one of two categories: alive and dead. While there are many healthy yellow and red stars which are hosting planets, there are also dead white dwarf stars which are unlike future versions of our sun, many of which feature disks of dust, gas, and shattered debris. How does a dying star reduce the first system to the second? In part by pulverizing its asteroids with next-level sunlight, recent research suggests.
When the Sun in 5 to 6 billion years balloons into a red giant, swallowing Mercury and Venus whole and scorching Earth, this will be just its first step in transforming the solar system. Since the Sun will grow so much larger, it will flood space with thousands of times more light than it currently does, like swapping out a lamp for a searchlight.
One of the most dramatic effects of this increased energy abundance will be to spin asteroids into much smaller pieces, suggests a recent publication in the Monthly Notices of the Royal Astronomical Society. The phenomenon could explain why astronomers see so many mini-asteroids falling into white dwarf stars. "We need to know where the debris is by the time the star becomes a white dwarf to understand how discs are formed. So the YORP effect provides important context for determining where that debris would originate."
The root cause of this mass destruction is electromagnetic radiation, according to modelling, and it has much to do with the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, named after the four scientists who contributed to understanding how this process works. The YORP effect occurs when the heat of a star changes the rotation of a small Solar System object - an asteroid, for example. The YORP effect could explain how the asteroid metals got. As asteroids crumble, they form a disc of asteroid dust around the white dwarf, some of which gets slurped down into the dead star.
Asteroids: Crash Course Astronomy from CrashCourse on YouTube:
Light energy from the expanded Sun is then absorbed by the asteroid, warming it up considerably. The heat then makes its way through the rock until it is emitted again in different directions as thermal radiation. This emission additionally generates a tiny amount of thrust over short time periods, this doesn't really change much, but over longer periods, it can cause an asteroid to spin or wobble off-axis.
"When a typical star reaches the giant branch stage, its luminosity reaches a maximum of between 1,000 and 10,000 times the luminosity of our Sun," explained astrophysicist Dimitri Veras of the University of Warwick.
The study of white dwarf stars as planetary systems is a fairly new field. When a sunlike star dies, it swells, expels a lot of its material, and eventually collapses, cramming a sun-like mass into an Earth-like space. That creates a powerful gravitational field that drags the star’s heavier elements into its center, leaving a pristine atmosphere of hydrogen with some helium. “I think of [white dwarves] as a blank sheet of paper,” says Mark Hollands, an astronomer at Warwick University.
A mysterious object located in a galaxy about 500 million light-years away from Earth is befuddling scientists with its highly unusual signals. It appears to be transmitting signals that reach Earth in a repeating, 16-day pattern, but researchers have no idea why.
Until now, such radio pulses appeared to be very random in timing. That changed when the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project (CHIME/FRB) discovered a repeating pattern.
The recently detected FRB, known as FRB 180916.J0158+65, sends out bursts that last for four days before stopping for 12 days and then repeating. The first 28 cycles were observed between September 2018 and October 2019 using the CHIME radio telescope in British Columbia.
"We conclude that this is the first detected periodicity of any kind in an FRB source," the study's authors said. "The discovery of a 16.35-day periodicity in a repeating FRB source is an important clue to the nature of this object."
Scientists recently pinpointed this specific FRB to a spiral galaxy known as SDSS J015800.28+654253.0, located half a billion light-years from Earth — making it the closest FRB ever detected. Researchers hope that tracing the burst's origin will help them to determine what caused it.
The very first FRB was discovered in 2007, and the signals have mystified scientists ever since. Most of the time they only last for a thousandth of a second, making them very difficult to study. Hundreds of these signals have been spotted so far, but only two have ever repeated themselves — and they seem to come from locations all over the universe.
While the cause of the repeating pattern is unknown, researchers said the FRB could be orbiting a black hole-like object, flashing its signal at a specific point in its orbital period.
According to another study looking at the same data, the pattern could be consistent with that of a binary star system containing a massive star and a dense neutron star. The neutron star could be emitting the bursts, which are sometimes hidden by winds caused by its massive friend.
"Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven't identified a possible natural source with any confidence," Avi Loeb, a Harvard-Smithsonian Center for Astrophysics theorist, said in a press release back in 2017.
There is one source most scientists have generally ruled out: aliens. But discovering more repeating FRBs may be the only way to know for sure.
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Credit: NASA's Mars Rover Opportunity
The IceCube Lab at the South Pole in Antarctica. Image: S. Lidstrom/NSF
Credit: Space.com