Month: January 2019

Spanish telescope images meteorites impacting the Moon

Brief “flashes” caused by impacts on the Moon have been seen for at least 1,000 years.

The European Space Agency (ESA) has released images of two meteorites impacting the Moon in mid-July, captured by the Moon Impacts Detection and Analysis System (MIDAS) installed on three separate telescopes in Spain.

Equipped with high-resolution CCD video cameras, the lunar observing system was built to record the brief flashes, known as “transient lunar phenomena,” produced when meteorites hit the Moon.

“For at least a thousand years, people have claimed to witness short-lived phenomena occurring on the face of the Moon. By definition, these transient flashes are hard to study, and determining their cause remains a challenge,” the ESA noted in a public statement.

“For this reason, scientists are studying these ‘transient lunar phenomena’ with great interest, not only for what they can tell us about the Moon and its history, but also about Earth and its future.”

The meteorites that hit the Moon on July 17 and 18, less than 24 hours apart, were likely pieces of the Alpha Capricornids summer meteor shower, which originates from the tail of Comet 169P/NEAT, the ESA statement reported.

Each of the parent meteoroids were no larger than an average walnut, scientists estimate.

Studying meteorite impacts on the Moon helps scientists better understand such impacts on objects throughout the solar system.

“By studying meteoroids on the Moon, we can determine how many rocks impact it and how often, and from this, we can infer the chance of impacts on Earth,” said MIDAS member and meteorite specialist Jose Maria Madiedo of the University of Huelva in Spain.

“At MIDAS, we observe impacts on the ‘dark side’ of the Moon, meaning impact flashes stand out against the dark lunar ground.”

The Moon’s “dark side” is any lunar region not lit by the Sun at a given time and should be distinguished from its “far side,” which perpetually faces away from the Earth.

Video footage of both impacts is available for viewing on the ESA website.

Distant galaxy forms stars at incredible pace, study reports

A newly discovered galaxy makes stars much, much faster than the Milky Way does.

Scientists working with Chile’s Atacama Large Millimeter/submillimeter Array (ALMA) have observed a galaxy that forms stars at an unprecedented rate, a new study published in Nature reports.

The distant “Monster Galaxy” — known as COSMOS-AzTEC-1 — came about roughly 2 billion years after the Big Bang. While it appears normal at first glance, it is unique because it generates over a thousand Suns worth of gas of stars each year.

That trait is important because, while scientists do not understand early galaxies, the new discovery could shed light on why certain systems form stars so fast.

When studying the new system, astronomers found that the clumpy gas inside of it has a stronger gravitational pull on itself than the force of the galaxy’s rotation from stars and supernovae. In addition, they also discovered it had two extra areas of gas-generating stars, rather than just one dense cloud of material.

“We found that there are two distinct large clouds several thousand light-years away from the center,” said lead author Ken-ichi Tadaki, a researcher at the Japan Society for the Promotion of Science and Japan’s National Astronomical Observatory, according to Space.com. “In most distant starburst galaxies, stars are actively formed in the center. So it is surprising to find off-center clouds.”

A team of international researchers found the galaxy while using ALMA’s 66 radio telescope dishes in the Chilean desert to look for signatures of carbon monoxide gas. Once they discovered it, they created a map based on what they found.

That showed the large, dense gas clumps inside AzTEC-1 are quite unstable and likely burn out within 100 million years of their formation. However, they form stars extremely quickly in that time.

Scientists are still not sure how galaxies like AzTEC-1 manage to build up so much gas before beginning their star formation, but they believe it could be the result of a galactic merger. Even so, as there is no evidence to support that process, more observations need to be done on such systems in the coming years to get a better idea of how they work.

“At this moment, we have no evidence of merger in this galaxy,” added Tadaki, according to Phys.org. “But by observing other similar galaxies with ALMA, we want to unveil the relation between galaxy mergers and monster galaxies.“

Intermediate black holes can bring stars back to life

A new study reveals that medium-sized black holes are able to briefly reignite dead stars.

If a dead star passes close to a medium-sized black hole it can come back to life for a brief moment, according to a new study published on the preprint site Arxiv.org and accepted for publication in The Astrophysical Journal.

This finding comes from a group of international astronomers, who performed a series of computer simulations that revealed what happens when a burned-out stellar corpse — also called a white dwarf — moves by an intermediate-mass black hole.

After analyzing the data, researchers found that the hole’s strong gravity can stretch and distort the dwarf in such a way that the elements inside its core reignite for a few seconds.

Those so-called “tidal disruption events” can also create gravitational waves that, while not detectable by current technology, could be picked up for study in the future.

The new study is important for a few reasons, but one of the biggest is that it sheds light on medium-sized black holes, which have proven difficult to study. Though many smaller and larger holes are on record, the middle ones are not easy to pin down. As a result, the more information on them, the better.

“It is important to know how many intermediate mass black holes exist, as this will help answer the question of where supermassive black holes come from,” study co-author Chris Fragile, a professor of physics and astronomy at the College of Charleston in South Carolina, according to Space.com.“Finding intermediate mass black holes through tidal disruption events would be a tremendous advancement.”

Another reason the finding is important is because it shows how the sun could die in the distant future. Every star that begins its life with about 8 solar masses or fewer will end up as a superdense white dwarf, and analyzing our star in light could provide more insight into the universe’s larger mechanisms.

New Horizons takes first picture of distant second target

Spacecraft’s photographs will help mission team refine the path to Ultima Thule.

More than four months before its scheduled flyby of Kuiper Belt Object (KBO) Ultima Thule, NASA’s New Horizons spacecraft captured its first image of its small second target.

The spacecraft’s Long Range Reconnaissance Imager (LORRI) photographed the dim KBO on August 16 from a distance of more than 100 million miles, surprising mission scientists, who did not expect any images of the object until September.

LORRI took a total of 48 images of the faint KBO against a dense background of stars, which it transmitted back to Earth via NASA’s Deep Space Network (DSN).

All previous images of Ultima Thule were either captured by the Hubble Space Telescope (HST) or obtained via ground-based telescopes when the KBO passed in front of a background star, casting a shadow.

Observations made between now and the January 1, 2019, flyby are of critical importance to the mission team, who will use them to refine the probe’s path to its closest approach, which will occur at 12:33 AM EST on New Year’s Day.

This initial detection confirms Ultima Thule is at the exact location where mission scientists expected it to be and indicates their calculations of its orbit are correct.

“Our team worked hard to determine if Ultima was detected by LORRI at such a great distance, and the result is a clear yes,” New Horizons principal investigator Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado, emphasized.  “We now have Ultima in our sights from much farther out than once thought possible. We are on Ultima’s doorstep, and an amazing exploration awaits.”

Hal Weaver of the Johns Hopkins University Applied Physics Laboratory (JHUAPL), New Horizons project scientist and LORRI principal investigator, described the challenge mission scientists faced in directing the spacecraft to photograph Ultima Thule from such a great distance.

“The image field is extremely rich with background stars, which makes it difficult to detect faint objects. It really is like finding a needle in a haystack. In these first images, Ultima appears only as a bump on the side of a background star that’s roughly 17 times brighter, but Ultima will be getting brighter–and easier to see–as the spacecraft gets closer.”

Located around one billion miles beyond Pluto, Ultima Thule will be the most distant object ever visited by a spacecraft and the first small KBO studied up close. New Horizons will break its own record in the flyby, set when it explored Pluto in July 2015.

Other records set by the spacecraft include taking the most distant photo of the Sun, imaging a galactic open cluster, and capturing distant images of two remote KBOs.

NASA releases image, video, of Saturn’s auroras

Data from Hubble and Cassini reveal remarkable similarities with Earth’s auroras.

Last year, while the Cassini spacecraft was still orbiting Saturn, NASA’s Hubble Space Telescope (HST) captured a stunning view of the planet’s northern aurora, which, after being combined with Cassini data, was just released as an image and video.

When Saturn experienced its summer solstice on May 24, 2017, meaning its north pole was tilted toward the Sun, both Hubble and Cassini observed and measured the northern aurora.

Although the aurora appears blue, it actually glows in ultraviolet wavelengths, which can only be seen from space. When hydrogen gas at the north pole interacts with energetic electrons generated by the planet’s powerful magnetic field, intense auroras are created. Because Saturn rotates rapidly on its axis, with a Saturn “day” taking just 11 hours, the auroras’ appearances constantly change.

The actual image and video released by NASA are composites that include images of the aurora taken in early 2018 and transformation of the May 2017 photos from ultraviolet wavelengths to visible light.

One of Cassini’s last images before it plunged into Saturn’s atmosphere last September revealed a never-previously-seen auroral storm produced by interactions between plasma in the planet’s magnetosphere and its upper atmosphere.

The spacecraft also tracked an arc-shaped structure within the aurora as it grew and eventually disappeared.

In a paper published in the journal Geophysical Research Letters, Cassini scientists noted the aurora bears a striking resemblance to auroras seen on Earth and attributed its creation to the solar wind, a stream of charged particles emanating from the Sun.

From the combined observations of both Hubble and Cassini, scientists learned that Saturn’s aurora strongly peaked just prior to the planet’s midnight, then did so again around dawn. Both midnight and dawn auroral spikes also occur on Earth.

New Horizons sets its sights on Kuiper Belt object

For the first time in history, the New Horizons spacecraft has glimpsed images of the space object Ultima Thule.

The New Horizons spacecraft has glimpsed the mysterious Kuiper Belt object known as Ultima Thule for the first time.

After spending quite a bit of time observing Pluto, NASA’s New Horizons has a new course set towards the Kuiper Belt. More specifically, its goal is the distant object Ultima Thule — an object that sits roughly 44 AU from the Sun.

Though it is still 107 million miles from Ultima Thule, the craft’s Long Range Reconnaissance Imager managed to snap roughly four dozen images of the celestial body. It then sent that data back to Earth, where NASA scientists used it to create a composite image and discern the dim object from all the background stars.

That revealed Ultimate Thule sits where astronomers originally thought it did, showing New Horizons is right on track.

“The image field is extremely rich with background stars, which makes it difficult to detect faint objects,” said Hal Weaver, a New Horizons project scientist,  according to Gizmodo. “It really is like finding a needle in a haystack. In these first images, Ultima appears only as a bump on the side of a background star that’s roughly 17 times brighter, but Ultima will be getting brighter—and easier to see—as the spacecraft gets closer.”

There are two reasons the newly compiled picture is so important. Not only does it give new insight into the Kuiper Belt, but it is also marks the most distant images ever taken from Earth. In addition, New Horizons also showed it has the ability to detect its target, which means the astronomers will be able to adjust the craft if needed.

NASA reports that New Horizons will move past Ultima Thule on January 1, 2019. That passing will mark the most distant object ever visited by a human-built spacecraft and give even more insight into Ultima Thune.

“Our team worked hard to determine if Ultima was detected by LORRI at such a great distance, and the result is a clear yes,” said Alan Stern, a researcher at the Southwest Research Institute, according to Phys.org. “We now have Ultima in our sights from much farther out than once thought possible. We are on Ultima’s doorstep, and an amazing exploration awaits!”

Japanese scientists determine age of asteroid Itokawa

Analysis indicates it came from large ancient parent body later destroyed in an impact.

Japanese scientists who analyzed samples taken from asteroid Itokawa and returned to Earth in 2010 by the Hayabusa probe determined the asteroid came from a parent body that formed 4.6 billion years ago, at the dawn of the solar system.

That body was destroyed in an impact with another asteroid approximately 1.5 billion years ago. Remnants from that impact stuck together over time, producing Itokawa.

Between 100,000 and 400,000 years ago, Itokawa was ejected from the asteroid belt between Mars and Jupiter and propelled into its current near-Earth orbit, where asteroids usually do not survive very long.

Scientists estimate Itokawa will either break apart or hit the Earth within the next million years.

Hayabusa was launched by the Japan Aerospace and Exploration Agency (JAXA) in 2003 with the goal of studying the near-Earth asteroid and returning a sample of it to Earth for analysis.

While Itokawa itself poses no current threat to Earth, near-Earth asteroids could potentially pose hazards to our planet. Understanding their formation and evolution processes is important for scientists in terms of both predicting and addressing potential impacts.

The Japanese scientists, including some from Osaka University, looked at tiny, phosphate-rich minerals found in the particles taken from Itokawa’s surface. They then measured the level of uranium inside the particles and determine how much of it had broken down into lead, a process that always occurs at the same pace. This allowed them to put together the asteroid’s history.

From this analysis, the scientists learned that the asteroid’s phosphate minerals crystallized during a time when the parent body experienced shock from an impacting object.

Another discovery the researchers made is that Itokawa’s mineralogy and geochemistry match those of low-iron, low-metal chondrite meteorites that often land on Earth. Chondrites are rocky, non-metallic meteorites that were never modified by melting of their parent bodies.

A paper detailing the scientists’ findings has been published in the journal Scientific Reports.

 

Scientists directly observe growth of infant exoplanet

Observation will give scientists new insights into the early stages of planet formation.

For the first time ever, scientists have observed a baby exoplanet in the process of growing by accreting material from the disk surrounding the star it orbits.

Using adaptive optics on the 6.5-meter Magellan Clay Telescope in Chile, a team of astronomers led by Kevin Wagner of the University of Arizona, Amherst College, NExSS and Earths in Other Solar Systems studied the 10-million-year old parent star, an orange dwarf known as PDS 70, located 370 light years from Earth.

Unlike most planets in the process of forming, which can be imaged only indirectly as gaps in the circumstellar disks surrounding young stars, PDS 70b has been seen directly as it accretes material from the disk surrounding its star.

“These disks around young stars are the birthplaces of planets, but so far, only a handful of observations have detected hints of baby planets in them. The problem is that until now, most of these planet candidates could just have been features in the disk,” said Miriam Keppler of the Max Planck Institute for Astronomy in Heidelberg, Germany, and leader of the group that initially discovered PDS 70b.

The researchers observed the system in hydrogen alpha and similar wavelengths on two nights last May. They detected hydrogen alpha emissions at the site of the planet, indicating hot hydrogen gas is falling onto it, a clear sign that it is still accreting material.

Even though it is a baby planet still in the process of forming, PDS 70b is already larger than Jupiter. Scientists estimate it has completed 90 percent of its growth and that it likely accreted material at a much faster rate in its early years than it is doing so now.

PDS 70b’s surface temperature is estimated to be approximately 1,382 degrees Fahrenheit (1,000 degrees Celsius), and its atmosphere is thought to be cloudy.

Being able to observe the process of a planet growing by gathering materials from a star’s circumstellar disk will give scientists new insight into the planet formation process.

The research team’s findings have been published in The Astrophysical Journal Letters.

OSIRIS-REx captures first image of its target asteroid Bennu

Probe that will return asteroid surface samples to Earth will arrive at its target in three months.

NASA’s OSIRIS-REx spacecraft has taken its first image of asteroid Bennu, from which it will retrieve soil samples that will be sent back to Earth for analysis.

Launched in September 2016, NASA’s first probe to a near-Earth asteroid has traveled approximately 1.1 billion miles. It will arrive at Bennu in December of this year and fly by the asteroid’s poles and equator before entering orbit.

From a distance of 1.4 millon miles, the spacecraft’s PolyCam camera photographed its target on August 17.

“Right now, Bennu just looks like a star, a point source. That will change in November, when we begin detailed observations, and we’ll start seeing craters and boulders. You could say that’s when our asteroid will transition from being an astronomical object to an actual geological object,” said OSIRIS-REx working group lead and University of Arizona Lunar and Planetary Laboratory (LPL) staff scientist Carl Hergenrother.

Between now and the probe’s arrival date, its science instruments, which include a thermal spectrometer, a visible and infrared spectrometer, a laser altimeter, and an X-ray spectrometer, will gather data about Bennu.

Early flybys will occur at distances ranging from 4.4 to 11.8 miles above the asteroid’s surface, a challenging maneuver because Bennu is so small and has very weak gravity.

Based on the spacecraft’s studies of Bennu, the mission team will select two possible sample collection sites. Collection will occur in July 2020, followed by a return to Earth. The samples will be placed in a Sample Return Capsule, which the probe will eject to land in the Utah desert in September 2023.

“The story of this asteroid is the story of our solar system. When we understand Bennu, we will understand something fundamental about our solar system,” stated OSIRIS-REx Camera Suite (OCAMS) instrument scientist Bashar Rizk.

PolyCam, one of three cameras on the spacecraft,  is designed to function as both a long-range acquisition camera that will photograph Bennu on approach, and as a reconnaissance camera, which will take detailed images of Bennu once OSIRIS-REx arrives at its target.

After conducting a slingshot or gravity assist maneuver around the Earth last December to raise it to Bennu’s orbital plane, OSIRIS-REx has been traveling close to 32,000 miles per hour on its way to Bennu.

“Now that OSIRIS-REx is close enough to observe Bennu, the mission team will spend the next few months learning as much as possible about Bennu’s size, shape, surface features, and surroundings before the spacecraft arrives at the asteroid,” explained OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona.

“After spending so long planning for this moment, I can’t wait to see what Bennu reveals to us.”

NASA hopes to return astronauts to the Moon in ten years

Plan calls for lunar space station to be crewed by 2024.

NASA is planning to send astronauts to a space station in lunar orbit by 2024 and return them to the surface of the Moon within 10 years.

These goals were announced on Monday, August 27, during a NASA presentation on the proposed lunar space station dubbed the Deep Space Gateway, which will be designed as an outpost for astronauts who will eventually travel into deep space.

Gateway’s features will include a habitat module for astronauts, a module to generate power and propulsion, and an airlock space vehicles can use to dock at the space station.

Like the International Space Station (ISS), Gateway will also serve as a site for science research.

While NASA hopes to build the power module through a partnership with a private company, no contracts for its construction have yet been awarded.  The space agency hopes to launch this module by 2022.

The power module will be launched on a commercial rocket while the habitat module will launch on NASA’s new large rocket, the Space Launch System (SLS), which will undergo its first flight, Exploration Mission 1 (EM-1), carrying an un-crewed Orion capsule around the Moon.

A second SLS mission, EM-2, is scheduled to carry astronauts around the Moon on the Orion capsule in 2022.

Following a third SLS launch, this time of a robotic mission to Jupiter’s moon Europa, NASA plans to launch the habitat module along with astronauts into lunar orbit on EM-3 in 2024. This launch will require a more powerful version of SLS, whose development is still in its early stages.

Last week, Vice President Mike Pence, in a speech at NASA’s Johnson Space Center in Houston, announced the goal of sending astronauts to Gateway before the end of President Donald Trump’s possible second term. That milestone will be followed by human landings on the Moon, possibly as soon as 2026.

Returning astronauts to the Moon will require construction of a lander that can carry them from Gateway to the lunar surface and back again. NASA plans to accomplish this in a partnership with private aerospace companies, starting with robotic landers and working up to crewed landers.

Meeting these goals will require development of much new technology and avoidance of the delays that have plagued the SLS program over the last few years.