Month: November 2018

Cosmic rays traced back to massive black hole

For the first time ever researchers have found an origin of the mysterious cosmic rays that come to Earth from outer space.

A team of international scientists have confirmed the source of ultra high-energy cosmic rays that beam to Earth from space, according to a new study published in the journal Science

Occasionally, our planet gets hit with protons and atomic nuclei that shoot out of space with energy so high that scientists cannot replicate it. Researchers first discovered those “cosmic rays” over 100 years ago, but they never knew where they came from until now.

In the new study, the team combined data from light and a single high-energy neutrino particle and found that the rays originate from a blazar — a supermassive black hole at the center of a galaxy.

That discovery could open up new insight into the universe and provide a brand new way to study the cosmos.

“We have been looking for the sources of cosmic rays for more than a century, and we finally found one,” study co-author Francis Halzen, lead scientist at the IceCube Neutrino Observatory and a professor of physics at the University of Wisconsin-Madison, told Space.com.

This finding came about when the IceCube detector at the South Pole spotted a neutrino particle that had an incredible amount of energy. The detector’s computers quickly calculated where it came from and sent the coordinates to astronomers across the globe.

Six days later, the Fermi Large Area Telescope found a distant blazer known as TXS 0506+056 in the same spot.

Further research showed the blazar is able to produce high-energy protons and nuclei, which then creates neutrinos. In that way, it can create the ultra high-energy cosmic rays that have eluded astronomers for the past century.

That is an exciting discovery, but it is just one source. As a result, more research needs to be done to explain all cosmic rays and how they get made.

“We clearly need more data. One source is not enough,” study co-author Spencer Klein, a physicist at Lawrence Berkeley National Lab, told Gizmodo. “Now that we found one accelerator, we’d like to find more and find out how they work.”

Exoplanet could potentially host life, study reports

A new method for determining a planet’s chemical makeup reveals that a distant rocky world has the potential to host life.

A newly discovered exoplanet known as Ross 128 b has the necessary makeup to support life, according to a recent study published in The Astrophysical Journal Letters.

A team of international astronomers at Brazil’s Observatório Nacional first spotted the rocky world last year. It sits 11 light years from Earth and orbits around a star known as Ross 128.

Though the planet is intriguing, it was the star that was at the center of the study.

Using the APOGEE spectrograph, researchers uncovered the body’s near-infrared light to determine its specific chemical makeup. That then revealed new information about Ross 128 b.

Ross 128 is a red dwarf. Though most stars in the galaxy — around 70 percent — classify as red dwarfs, they still of interest to astronomers because they are cooler than the sun and most of them have planets.

Those lower temperatures are important because their habitable Goldilocks zone — the temperate region around a host star where a planet needs to exist in order to theoretically support life — is a lot closer than the distance between the Earth and the sun.

Unfortunately, most red dwarfs are quite active. They belch out dangerous flares that are so hot they would burn any life on nearby planets.

In contrast, Ross 128 has minimal flare activity, suggesting its a good place to look for life.

Though the team initially wanted to study Ross 128 b, it orbits the star at such an angle that makes it impossible to study directly. As a result, analyzing the star is the next best choice.

“The ability of APOGEE to measure near-infrared light, where Ross 128 is brightest, was key for this study,” said study co-author Johanna Teske, a researcher at the Carnegie Institution for Science, in a statement. “It allowed us to address some fundamental questions about Ross 128b’s ‘Earth-like-ness.'”

Researchers used the APOGEE spectrograph to analyze the star’s near infrared spectrum and determine how much carbon, oxygen, magnesium, aluminum, potassium, calcium, titanium, and iron it contains. That then allowed them to understand its composition.

For instance, the analysis revealed that Ross 128 b is likely a rocky planet that is larger than Earth and sits in the Goldilocks zone.

There are still many unanswered questions about the world, including what its magnetic field is like, if it has an atmosphere, and what weather conditions are hospitable for life.

Even so, this study shows the validity of using a star to study planets that cannot directly be observed and suggests the method could one day uncover information about other far-off exoplanets.

“It’s exciting what we can learn about another planet by determining what the light from its host star tells us about the system’s chemistry,”said lead author Diego Sauto, a researcher at the Observatorio Nacional in Brazil, according to Science Alert.

Near-Earth asteroid is actually a binary system

Discovery gives scientists opportunity to better understand binary asteroids’ formation processes and compositions.

A near-Earth asteroid discovered last year is actually a binary system of two objects that orbit one another, according to observations conducted by three of the world’s largest radio telescopes.

Asteroid 2017 YE5, found by the Morocco Oukaimeden Sky Survey on December 21, 2017, is the fourth “equal mass” binary near-Earth asteroid ever found. “Equal mass” binaries are systems of two objects almost identical in size and mass orbiting but not touching one another.

Exactly six months after 2017 YE5’s discovery, on June 21 of this year, the asteroid made its closest approach to Earth for the next 170 years, coming about 16 times the Earth-Moon distance, or 3.7 million miles (six million km) of our planet.

Because nothing was known about the asteroid’s physical properties, researchers at three separate observatories took advantage of its close approach and turned their radio telescopes to the object.

NASA’s Goldstone Solar System Radar (GSSR), located in California, found the first signs that the asteroid is really two objects, revealing two lobes.  Scientists could not tell whether the lobes were or were not attached to one another until the objects’ rotations revealed a gap between them.

After being alerted to the fact that 2017 YE5 showed signs of being a binary, scientists at the Arecibo Observatory in Puerto Rico and at the Green Bank Observatory (GBO) in West Virginia set up their radio telescopes to work together to study the object through an arrangement known as a “bi-static radio configuration.” The setup involved Arecibo transmitting a radio signal and Green Bank receiving the return signal.

The joint effort confirmed the asteroid’s status as a binary system, revealing the two objects orbit each other once every 20 to 24 hours.

Observations of the asteroid in visible light by astronomers at the Center for Solar System Studies in Rancho Cucamonga, California, confirmed the rotation data.

Radar data revealed the objects do not reflect the level of sunlight typical of rocky asteroids, meaning they have dark surfaces. The two objects show different levels of radar reflectivity, an unusual feature for binary asteroid systems. Differences in their radar reflectivity could indicate they have different density levels, surface roughness, and near-surface compositions.

According to scientists’ estimates, approximately 15 percent of near-Earth asteroids 650 feet (200 meters) or larger are binaries, but most consist of a larger object orbited by a smaller one rather than two equal-mass bodies. Another 15 percent of near-Earth asteroids this size or larger are contact binaries, in which two objects of roughly the same size touch one another while orbiting each other.

As a next step, researchers hope to determine the densities of 2017 YE5’s two components by analysis of both radar and optical observations.

 

Scientists examine Voyager-1 data in search of dark matter particles

Voyager’s pristine cosmic ray data is allowing researchers to form the bounds of the cosmos’ dark matter.

NASA’s Voyager-1 spacecraft is sending back cosmic ray data that has allowed researchers to better understand the cosmos’ exotic dark matter, reports Bruce Dorminey for Forbes Magazine. What they found was that analysis of the spacecraft’s cosmic ray detections beyond the heliopause (where the solar wind’s influence ends and the flux of low energy galactic cosmic rays begins), provided no evidence of dark matter. The researchers theorized that if dark matter was present, they would have found a higher density of lower energy cosmic rays in the data.

Caltech physicist Alan Cummings, who is part of the Voyager science team, explains that Voyager’s cosmic ray detector was designed specifically to look for galactic cosmic rays—low-energy cosmic rays that can only be detected outside our solar system. While most scientists believe cosmic rays originate within supernova remnants, some are thought to be related to dark matter. These rays—charged elemental particles that sometimes move at velocities approaching that of light—are helping researchers understand dark matter’s lower mass limits. The idea is that at least some dark matter particles present in the galaxy will annihilate into particle-antiparticle pairs, Dorminey writes—however, this is rare.

Scientists have proposed that dark matter could be made of microscopic black holes. A microscopic black hole would be no bigger than a nucleus of the element Xenon, explains Pierre Salati, a physicist at France’s Laboratoire d’Annecy-le-Vieux de Physique théorique. Researchers hoped that analyzing the new Voyager data to look for the evaporation of black holes emitting cosmic rays would be observable. But it wasn’t, leading Salati to conclude that these cosmic rays may not exist. “The idea is that the black holes evaporate and that evaporation emits cosmic rays,” he said. Despite the lack of evidence, researchers still plan to analyze data sent back from Voyager as long as possible.

Nearby rocky exoplanet could be habitable

Chemical composition of host star can inform scientists about the nature of orbiting planets.

A rocky exoplanet 11 light years away may not be an Earth twin but likely has a temperate climate that could sustain liquid water on its surface.

Known as Ross 128 b, the planet was discovered last fall by researchers who used the Sloan Digital Sky Survey’s (SDSS) APOGEE spectroscopic instrument. It orbits a red dwarf star, Ross 128, that is smaller, cooler, and dimmer than our Sun.

Scientists estimate 70 percent of stars in the galaxy are red dwarfs, most of which likely have at least one orbiting planet.

Now, a group of researchers led by Diogo Souto of Brazil’s Observatorio Nacional and by Johanna Teske of the Carnegie Institution for Science measured the chemical composition the star using APOGEE in the near-infrared and found signs of carbon, oxygen, magnesium, aluminum, potassium, calcium, titanium, and iron.

Knowing which elements are present in a star helps researchers predict the type of exoplanets that might be orbiting that star and whether any of those planets could be habitable.

“Until recently, it was difficult to obtain detailed chemical abundances for this type of star,” explained Souto, who last year pioneered a new technique to obtain this information.

“The ability of APOGEE to measure near-infrared light, where Ross 128 is brightest, was key for this study. It allowed us to address some fundamental questions about Ross 128 b’s ‘Earth-like-ness,'” Teske explained.

A star’s chemical content influences the protoplanetary disk of gas and dust that rotates around it in its early days. Planets form within these disks, and a star’s chemistry therefore influences its interior structure, mineraology, mass, and layering.

Ross 128 was found to have an iron level similar to that of our Sun. Based on its ratio of iron to magnesium, the researchers believe Ross 128 b has a larger core than the Earth has.

Once they had a good estimate of the planet’s mass and chemical abundance, the scientists were able to come up with a range for its radius.

Knowing a planet’s mass and radius enables scientists to calculate its bulk density.

Planets with 1.7 or more Earth radii are not considered habitable, as they are likely surrounded by a layer of gas, meaning they resemble our solar system’s ice giants.

In contrast, planets with lower radii, as Ross 128 b appears to have, are expected to be more rocky than gaseous.

The researchers also measured the exoplanet’s temperature and estimated how much of the star’s light reflects off its surface, which indicated it has a temperate climate.

“It’s exciting what we can learn about another planet by determining what the light from its host star tells us about the system’s chemistry,” Souto  noted. “Although Ross 128 b is not Earth’s twin, and there is still much we don’t know about its potential geologic activity, we were able to strengthen the argument that it’s a temperate planet that could potentially have liquid water on its surface.”

A paper detailing these findings has been published in The Astrophysical Journal Letters.

 

Pieces of ‘fireball’ meteorite found in Botswana

Researchers have successfully tracked down pieces of the small meteorite that recently exploded above Africa.

Meteorite hunters have recovered a fragment of a small asteroid that crashed down to Earth on June 2nd after burning up in the atmosphere above Botswana.

The space rock exploded a few hours after researchers first detected it, breaking into several pieces upon contact with Earth’s atmosphere.

After that initial impact, the asteroid then exploded and turned into what is known as a “fireball” meteor. That means it created a bright flash of light as it sped across the sky.

As soon as skywatchers spotted the falling rock, teams of meteor experts set out to find any pieces that may have survived the harsh trip down to the ground.

Five days after the hunt began, a team made up of geoscientists from local universities and research institutes uncovered the first piece. Soon after, a group of international scientists joined the search and recovered a second piece in Botswana’s Central Kalahari Game Reserve.

Astronomers then further narrowed down potential locations by collecting and analyzing footage from surveillance cameras.

“After disruption, the asteroid fragments were blown by the wind while falling down, scattering over a wide area,” said officials with the University of Helsinki, according to Space.com. Studying the footage allowed them to “get better constraints on the position and altitude of the fireball’s explosion.”

Astronomers at the Catalina Sky Survey first detected the asteroid 8 hours before it hit Earth. At the time they determined the rock measured roughly 6 feet across.

While that size was much too small to send an alert, the team did use impact prediction models to see where it may have landed and help in the search.

Some of the pieces have been recovered, and astronomers will continue to look for more as the days go on. Finding the fragments is important because they could lead to new research and help scientists get a better idea of what the rock was like.

“We see it as our mandate and duty to respond quickly to events like this one and to recover the material, both for research purposes and as part of the heritage of Botswana,” said Alexander Proyer, leader of the expedition, according to Popular Mechanics. “This meteorite is a priceless piece of rock that the people of Botswana will want to enjoy seeing on display for generations to come.”

First global maps of Pluto and Charon published

Maps created in painstaking process from digital images captured by New Horizons’ cameras.

Using images and data returned by NASA’s New Horizons spacecraft in 2015, members of the mission science team have created and published global topographic maps of Pluto and its largest moon Charon.

Led by New Horizons senior staff scientist Paul Schenk of the Lunar and Planetary Institute (LPI), the scientists embarked on the labor-intensive project by gathering all the images taken by the spacecraft’s Long Range Reconnaissance Imager (LORRI) and Multispectral Visible Imaging Camera (MVIC).

They then assembled mosaics for both worlds, carefully aligning surface features in overlapping images. For each region, the scientists used digital analysis of photos taken by both cameras to  create topographic maps. These maps were then integrated into complete topographic maps for both Pluto and Charon.

Over the year-and-a-half during which New Horizons sent back its Pluto data, the researchers were able to create higher quality geographic and topographic maps.

In the final product, each area on Pluto and Charon lit by the Sun is depicted in the highest possible resolution. Individual elevations and the wide variety of terrains on both worlds are clearly visible.

On the Pluto map, viewers can see the steep, icy tops of the planet’s highest mountains, known as the Tenzig Montes range. Located to the southwest of the left side of Pluto’s heart feature, a nitrogen glacier known as Sputnik Planitia, these mountains have slopes of 40 degrees or greater.  The tallest peak sits 3.7 miles (six km) above the mountain range’s base.

Tenzig Montes’s mountains are made up of hard water ice, the only ice powerful enough to hold them up. Other volatile ices on Pluto’s surface, such as methane and nitrogen ice, are not strong enough to hold up such structures and keep them from collapsing.

Several large-scale features not visible in the global mosaic map can be seen in the topographic map. Among these are differences in ice depth in the center versus the outer edges of Sputnik Planitia. Ice depth at the center of the 625-mile (1,000-km) glacier extends 1.5 miles (2.5 km) while at the outer edges reaches as far as 2.2 miles (3.5 km) below Pluto’s sea level, also known as its mean elevation.

Also visible in the topographic map are highly eroded areas of ridges and troughs stretching north to south for about 2,000 miles (3,000 km) close to Sputnik Planitia’s western edge. While this feature is considered evidence of ancient fracturing, scientists do not know why such fracturing would have occurred only in this one area.

Mountain ridges reaching heights between 2.5 and 3.1 miles (four and five km) are also seen on Charon. Scientists believe these formed when the large moon’s outer crust fractured as a subsurface ocean froze.

Fractured terrain and blocky regions may have been caused by cryovolcanism. Trouphs up to 8.7 miles deep (14 km) are seen near Charon’s north pole and in its equatorial regions.

Available for use by the scientific community and the public, the maps have been archived with NASA’s Planetary Data System.