Month: December 2018

Mars orbiters studying global dust storm

Scientists hope to learn why some annual local dust storms become global events.

NASA’s Mars orbiters have been taking advantage of the rare dust storm that has engulfed the Red Planet for weeks to study its  effects on the Martian atmosphere and surface.

Dust storms that envelop the entire planet occur approximately once every three to four Martian years, or every six to eight Earth years.

In this case, a small, localized dust storm that formed on May 30 began a series of runaway storms that by June 20 created a dust cloud surrounding the entire planet.

On the ground, NASA’s Opportunity rover, which requires sunlight to recharge its batteries, went dormant and stopped communicating with Earth. However, the dust covering the rover acts as insulation, preventing its temperatures from dropping too low.

NASA’s Curiosity rover, which is nuclear-powered, can operate without sunlight and is studying the storm from its surface vantage point.

The majority of data on the storm is being collected by NASA’s Mars Reconnaissance Orbiter (MRO), Mars Odyssey, and Mars Atmosphere and Volatile EvolutioN (MAVEN).

Two MRO science instruments, the Mars Color Imager (MARCI) and the Mars Climate Sounder (MCS) are actively studying the storm. MARCI is tracing the storm’s evolution by mapping the planet during Martian afternoons while MCS is measuring changes in atmospheric temperatures at various altitudes.

When dust in the Martian atmosphere is heated by the Sun, wind patterns across the planet and even circulation of the entire atmosphere are altered. These temperature changes affect the storm by altering wind directions and carrying more surface dust into the atmosphere.

“The very fact that you can start with something that’s a local storm, no bigger than a small [U.S.] state, and then trigger something that raises more dust and produces a haze that covers almost the entire planet is remarkable,” said MRO project scientist Rich Zurek of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.

Through its Thermal Emission Imaging System (THEMIS), Mars Odyssey is tracking Mars’s surface and atmospheric temperatures and measuring atmospheric dust levels, all of which help scientists learn how such storms grow, evolve, and dissipate.

“This is one of the largest weather events we’ve seen on Mars. Having another example of a dust storm really helps us to understand what’s going on,” emphasized Michael Smith of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who works on THEMIS.

MRO has increased its atmospheric observations from every 10 days to twice a week since the storm began.

Instead of studying the storm, MAVEN is focusing on how it impacts Mars’s upper atmosphere approximately 62 miles (100 km) above the surface. This orbiter’s primary goal is to determine the fate of ancient Mars’s atmosphere, and its findings suggest that atmosphere was stripped by the solar wind between 3.5 and four billion years ago.

MAVEN scientists hope to learn whether atmospheric escape is altered when dust traps heat from the Sun. A warmer atmosphere may have caused ancient water vapor to rise to a position where it was broken up by sunlight, causing its hydrogen atoms to escape into space.

 

Distant star caught devouring planet

Researchers have finally observed a star devouring a planet.

For the first time in history astronomers have witnessed a star devouring a planet, a new study published in the Astronomical Journal reports.

This discovery comes from a team of international scientists who used NASA’s Chandra X-Ray Observatory to capture the event, which took place 450 light years from Earth.

They believe a large star known as RW Aur A swallowed a pair of newborn planets that smashed into each other before collapsing down into the fiery body’s rotating disk.

The team first took note RW Aur A some 80 years ago. Since that time, they have noted that it sits in the constellation Taurus-Auriga and is part of a binary system with another star that weighs as much as the sun. 

However, what makes it particularly interesting is that it goes through a pattern where it dims for extended periods of time before slowly brightening again.

To explain its recent dimming, the team in the new study took a closer look at the star. They found that it may have gotten blocked by a thick cloud of gas and dust created by two planets smashing together and then falling into the star. That would have blocked out its light.

While computer models have long predicted that young stars can devour planets, this is the first scientists have observed such an event.

“If our interpretation of the data is correct, this would be the first time that we directly observe a young star devouring a planet or planets,” said lead author Hans Moritz Guenther, a researcher at the Massachusetts Institute of Technology, according to Tech Times.

This new information is important because, not only does it mark a never-before-seen event, it could explain previous dimming episodes as well. For example, if two planets or the remains of past collisions crashed into each other it may have created debris that spun off on rogue orbits.

The new finding marks a brand new phenomenon. Researchers hope they can shed more light on it in the future.

“Computer simulations have long predicted that planets can fall into a young star, but we have never before observed that,” added Guenther, according to Science Daily. “If our interpretation of the data is correct, this would be the first time that we directly observe a young star devouring a planet or planets.”

Passing star may have perturbed outer solar system

Orbits of outer solar system objects are warped and distorted.

A star that passed close to our solar system several billion years ago may have perturbed outer solar system objects, according to a new study based on computer simulations led by Susanne Pfalzner of the Max Planck Institute for Radio Astronomy in Bonn, Germany.

Many dwarf planets and smaller Trans-Neptunian Objects (TNOs) beyond the orbit of Pluto have extremely inclined, eccentric orbits, which scientists are hard pressed to explain. For example, dwarf planet Sedna takes 11,400 years to complete a single orbit around the Sun.

Additionally, the outer solar system is emptier than researchers think it should be.

Although Neptune orbits further from the Sun than Uranus, it is more massive, posing yet another puzzle.

These anomalies led researchers to propose a rogue star passed close to the solar system in its early days, in the process scattering thousands of distant, icy worlds into unusual positions and orbits.

“You could well have a hybrid scenario, where the movement of the planets is responsible for the things we find in the inner solar system, like the low mass of Mars, and a flyby [is responsible] for the properties of the outer solar system,” Pfalzner said.

Using data on the behavior of young stars, the researchers conducted a computer simulation of a stellar flyby to determine whether the passage of a rogue star could have caused the current arrangement of the outer solar system.

According to the simulation, the chances of a star having done this over a period of one billion years are approximately one in four, meaning this likely occurred at some point in the solar system’s early years.

Specifically, the simulation determined that a star with a mass similar to that of our Sun could have created the dynamics seen in the outer solar system if it passed within 80 to 100 astronomical units (AU, with one AU equal to the average Earth-Sun distance or 93 million miles) while the system was still forming.

During its passage, the star could have flung thousands of tiny, icy worlds beyond Pluto into interstellar space, leaving the outer solar system with the empty regions it has today.

The researchers plan to further test their theory by adding more detail to their computer simulations.

A paper on their findings has been accepted for publication in the Astrophysical Journal.

 

Astronomers capture first-time images of planet formation

Scientists have spotted the formation of a gas giant 370 light years from Earth.

Astronomers say that they have captured the first confirmed image of the formation of a planet, reports Nicola Davis for The Guardian. The image shows a bright object travelling through the dust and gas surrounding PDS70, a young star about 370 light years from Earth. The event was captured by the European Southern Observatory’s Very Large Telescope.

Astronomers report that the newly formed planet is a gas giant with a mass greater than Jupiter, and far away from its star—about as far as Uranus is from our sun. “These discs around young stars are the birthplaces of planets, but so far only a handful of observations have detected hints of baby planets in them,” explains Miriam Keppler of the Max Planck Institute for Astronomy in Germany, and lead author of the research. “The advantage of our detection is that we have detected [the new planet] with several different observing instruments, different filter bands and different years,” she added. She explains that the star around which the new planet orbits is just five to six million years old, which could make the planet even younger.

It is possible that the planet has neighbors, or that other planets could appear over time, as Dr. Zoe Leinhardt, a computational astrophysicist explained about the discovery. “The way that planets form, a large Jupiter-mass planet would be the easiest to see … and also those large planets would form more quickly.” She believes that this indicates planet formation is ongoing in the system. Astronomers now have the task of carrying out observations to explore how the planet develops, especially in light of its distance from its star—one that defies current planet formation theories.

New interferometer telescope array will spy on satellites

The observatory could give optical interferometry a boost in future decadal reviews.

Over the next few years, there are plans to build 1.4 meter telescopes similar to the instrument being installed this month atop South Baldy Mountain in New Mexico. Despite the billion-dollar telescopes grabbing headlines, these smaller lensed telescopes will surpass any other optical telescope in its eye for detail, writes Adam Mann for Science.

The $200 million Magdalena Ridge Observatory Interferometer (MROI) is set to be completed by 2025, and will have the equivalent resolution of a large telescope 347 meters across. Combining light from the spread-out telescopes will allow the instrument to make out small structures on stellar surfaces, image dust around newborn stars, and view supermassive black holes at the center of some galaxies. It will even be able to spy on spy satellites making out details as small as a centimeter across on satellites 36,000 kilometers above Earth. The U.S. Air Force is funding MROI to take advantage of these capabilities. As Michelle Creech-Eakman, an astronomer at the New Mexico Institute of Mining and Technology, explains it, “they want to know: Did the boom break or did some part of the photovoltaic panels collapse?”

Still, MROI, and optical interferometry in general, has made slow progress. Because the short wavelengths of visible light cannot yet be digitized by any electrical system, the light must be merged in real time, with nanometer precision. “Interferometry is still something of a dirty word around NASA,” says Gerard van Belle, chief scientist at the Navy Precision Optical Interferometer. But, support is still there for this instrument. Once complete, MROI’s telescopes will be more widely separated than any other interferometer, enabling its superior resolution.

Hayabusa2 captures closeup image of asteroid Ryugu

Boulders and dust photographed following free fall experiment.

Japan’s Hayabusa2, a spacecraft on a mission to return an asteroid sample to Earth, captured a closeup image of its target revealing surface features just a few feet in diameter.

The Japan Aerospace Exploration Agency’s (JAXA) Hayabusa2 probe entered orbit around asteroid 162173 Ryugu on June 27 of this year. In practice for its eventual landing on the asteroid, it descended from a height of 12.5 miles (20 km) to a distance of just 2,792 feet (851 meters) above the surface after spending 21 hours in free fall.

From a distance of just 0.6 miles (one km), Hayabusa2 trained its Optical Navigation Camera–Wide Angle on Ryugu’s surface, revealing large rocks and dust.

Mission controllers conducted the descent on August 6 for the purpose of gaining a better understanding of the asteroid’s gravity.

“By monitoring the exact movement of the Hayabusa2, we can see how strong the gravitational attraction is from Ryugu,” a JAXA statement explained.

Several images of Ryugu were taken as the spacecraft fell toward the asteroid.

Although Ryugu occasionally crosses Earth’s orbit and is classified as a potentially hazardous asteroid, it poses no threat to our planet. However, by studying its composition, scientists will likely gain valuable insight into appropriate methods of deflecting or destroying any similar asteroids that may one day pose such threats.

Studying Ryugu’s composition will also provide researchers with important information about the history of the solar system.

In 2010, JAXA’s first asteroid sample return mission, Hayabusa, successfully brought back samples of asteroid 25143 Itokawa to Earth.

The Hayabusa2 spacecraft, launched in December 2014, was built with improved ion engines, navigation technology, guidance technology, antennas, and attitude control systems. It will drop a lander and three rovers onto Ryugu’s surface and use an explosive device to obtain samples of its subsurface.

After collecting samples multiple times, Hayabusa2 will leave Ryugu in December 2019 and return home a year later.

Following its successful closeups of the asteroid, Hayabusa2 fired its thrusters and returned to an altitude of approximately 3.1 miles (five km) above its target’s surface.

Satellite data shows acceleration of Arctic carbon cycle

Region is behaving more like a boreal forest than a tundra.

Satellite data collected under NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) confirms the Arctic carbon cycle is speeding up due to warming temperatures, causing the region to act more like a North American boreal forest than like icy tundra.

Boreal forests are those found in regions south of the Arctic, specifically cold, temperate regions.

A NASA research team analyzed over 40 years of carbon dioxide surface measurements acquired by the National Oceanic and Atmospheric Administration’s (NOAA) observatory in Barrow, Alaska, using a standard computer model geared toward ecosystem carbon balance in a study to determine the rate at which carbon is moving into and out of Alaska’s North Slope.

While computer models used in earlier studies indicated an acceleration in the region’s carbon cycle, satellite data, along with information collected from the area’s air and surface, show that acceleration to be greater than any of the models predicted.

Carbon in the North Slope’s tundra regions now spends 13 percent less time trapped in frozen soil than it did four decades ago, the researchers determined.

“Warming temperatures mean that essentially we have one ecosystem–the tundra–developing some of the characteristics of a different ecosystem–a boreal forest,” said Anthony Bloom of NASA’s Jet Propulsion Laboratory (JPL) in California. “While various factors regulate how fast this transformation will continue to occur, studies using Landsat and MODIS satellite imagery with field measurements over the past decades have observed a northward migration of shrubs and trees.”

Landsat is a joint program between NASA and the United States Geological Survey (USGS) of Earth-observing satellites that provide the longest continuous space-based Earth observations. The Moderate Resolution Imaging Spectroradiometer (MODIS) is a satellite that observes every point on Earth in discrete spectral bands every one to two days.

The Arctic carbon cycle involves the release of carbon dioxide during Arctic summers, when warmer temperatures melt the top layers of permafrost, allowing microbes to break down organic matter that had been frozen in colder weather. This triggers plant growth, with plants removing the carbon dioxide as they conduct photosynthesis.

Overall warmer temperatures mean the carbon dioxide spends less time frozen in the soil and more time in the atmosphere, a phenomenon that could have global consequences.

“The balance between these two dynamics will determine whether Arctic ecosystems will ultimately remove or add atmospheric carbon dioxide in the future climate. Our study finds the latter is more likely. We anticipate that residence time of Arctic carbon will lead to faster and more pronounced seasonal and long-term changes in global atmospheric carbon dioxide,” said former JPL researcher Sujong Jeong of Seoul National University.

A paper on the study has been published in the journal Science Advances.

Perseid meteor shower to peak this weekend

Lack of visible Moon will make this the year’s best meteor shower.

Skywatchers will have ideal viewing conditions to watch the annual Perseid meteor shower, which will peak this weekend, between August 10 and 13.

Named for the Perseus constellation from which it originates, this meteor shower is visible every year in August when Earth passes through debris from the comet Swift-Tuttle. A short-period comet, Swift-Tuttle takes 133 years to circle the Sun. Each time it makes its closest approach, the Sun’s heat and tidal forces cause pieces of it to break off, leaving behind a debris field.

The Perseids will be especially bright this year because the meteor shower occurs at the new Moon, when the Moon will not be present to brighten the sky and obscure the meteors. Night skies without a Moon are darker and provide the best opportunities for meteor viewing.

“This year, the Moon will be near new Moon; it will be a crescent, which means it will set before the Perseid show gets underway after midnight. The Moon is very favorable for the Perseids this year, and that’ll make the Perseids probably the best shower of 2018 for people who want to go out and view it,” NASA meteor specialist Bill Cooke told the website Space.com.

On Saturday night August 11, viewers with dark skies should be able to see between 60 and 70 meteors per hour. An online map of areas across the country with the least light pollution, created by a research team at the Cooperative Institute for Research in Environmental Sciences (CIRES) and Chris Elvidge of the National Oceanic and Atmospheric Administration (NOAA) is available to guide viewers to the best locations.

Both the brightness of meteor showers and the number of meteors visible are determined by several factors, including the density of the debris field, the debris field’s relative speed in relation to Earth, the distance between Earth and the debris field, and the degree of light pollution at a viewing site.

Observers should allow approximately 30 minutes for their eyes to adapt to the dark.

While the shower peaks this weekend, Perseid meteors can be seen any clear night between July 17 and August 24.

Spitzer telescope images supernova remnant

Precursor star exploded between 80,000 and one million years ago.

NASA’s Spitzer Space Telescope, which observes in infrared wavelengths, photographed one of the Milky Way’s largest supernova remnants in exquisite color and detail.

Supernova remnants are clouds left behind after a massive star explodes in a supernova after running out of fuel. Designated HBH 3, this particular remnant, which has a diameter of approximately 150 light years, was first detected by radio telescopes in 1966.

In addition to being one of the largest known supernova remnants, HBH 3 is also one of the oldest. Scientists estimate its precursor star exploded sometime between 80,000 and one million years ago.

Extremely high-energy light in the form of gamma rays was detected coming from near HBH 3 in 2016 by NASA’s Fermi Gamma-Ray Telescope.  Some scientists theorize that particles being emitted by the supernova remnant are exciting gas in nearby star-forming regions.

Supernova remnants emit both infrared and optical light. A white, cloud-like feature toward the left side of the Spitzer image is actually three separate star-forming regions, designated as W3, W4, and W5. Located 6,400 light years away, these regions extend far beyond what is seen in the image.

Red filaments seen in the center and top of the photo are made up of molecular gases, which were both produced and energized in the supernova explosion, causing them to radiate infrared light.

Infrared light is slightly less energetic than optical light. In this photo of HBH 3, infrared wavelengths of 3.6 microns are mapped to blue while those of 4.5 microns are mapped to red. The filaments radiate light solely at the 4.5-micron wavelength.

The white, star -forming region is a combination of both wavelengths.

To end their lives as supernovae, stars must have a minimum of eight to 15 solar masses.

As of August 25, Spitzer will mark 15 years of being in space.

 

“Green” comet makes closest approach to Earth

Originating from the Oort Cloud, comet is on its first trip to the inner solar system.

A green-colored comet is making its closest approach to Earth on Tuesday, August 7, as it travels on its first ever journey through the inner solar system.

Discovered with the PanSTARRS telescopes in Haleakala, Hawaii, on September 23, 2017, and designated C/2017 S3, the comet has undergone two recent outbursts, one on June 30, and the other two weeks later.

Many comets experience outbursts in which they brighten. For this unusually large comet, which came from the Oort Cloud, a reservoir of comets in the outer solar system beyond the Kuiper Belt, these outbursts give it a greenish tinge. Its second eruption produced a large gas cloud surrounding the comet that swelled to 161,000 miles (260,000 km) in diameter.

C2017 S3’s green color is the result of the ionization of its carbon and cyanide molecules due to warming from the Sun. Ionization involves the separation of electrons and protons, which produces the trademark green glow, as explained by Brian Koberlein of the Rochester Institute of Technology (RIT) in New York.

At closest approach, the comet will come within 70 million miles (112 million km) of the Earth, then head toward the Sun. It will swing around the Sun on August 16 and then head back to the distant Oort Cloud.

While C2017/S3 is currently too close to the Sun to be visible, observers will get the chance to see it after it begins heading back toward the outer solar system later this month, noted Paul Chodas, manager of the Jet Propulsion Laboratory’s (JPL) Center for Near-Earth Object Studies (CNEOS).

Regular outbursts by comets were long thought to be caused by surface heating and pressure buildup that produce explosions on their surfaces as they head toward the Sun. However, this theory was called into question by the Rosetta spacecraft’s close observations of Comet 67P/Churyumov-Gerasimenko, whose data pointed to dust kicked up and out into space by landslides on the comet’s surface as the outbursts’ cause.

The comet’s close approach involves no threat to Earth.

A 3D interactive  visualization of the comet produced by JPL is available for public viewing.