Space: The Final Frontier

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Meteor showers dig up water on the moon

Water molecules released from the surface suggest water is buried in the moon’s soil

Meteor showers bring moon geysers. A lunar orbiter spotted extra water around the moon when the moon passed through streams of cosmic dust that can cause meteor showers on Earth.

The water was probably released from lunar soil by tiny meteorite impacts, planetary scientist Mehdi Benna of NASA Goddard Space Flight Center in Greenbelt, Md., and colleagues report April 15 in in Nature Geoscience. Those random impacts suggest water is buried all over the moon, rather than isolated in freezing dark craters — and that the moon has been wet for billions of years.

Samples of lunar soil brought back by the Apollo astronauts suggested that the moon is bone dry. But in the last decade or so, several remote missions have found water deposits on the moon, including signs of frozen surface water in regions of permanent shadow near the poles (SN: 10/24/09, p. 10).

“We knew there was water in the soil,” Benna says. What scientists didn’t know was how widespread that water was, or how long it had been there.

Benna and colleagues used observations from NASA’s LADEE spacecraft, which orbited the moon from November 2013 to April 2014 (SN Online: 4/18/14). LADEE’s spectrometers detected dozens of sharp increases in the abundance of water molecules in the moon’s exosphere, the tenuous atmosphere of gas molecules that clings to the moon. Twenty-nine of those measurements coincided with known streams of space dust.

When Earth passes through those streams, the dust burns up in the atmosphere, producing annual meteor showers like the Leonids and the Geminids. But because the moon has no true atmosphere, bits of dust from the same showers strike the moon’s surface directly, stirring up what lies beneath.

Benna and colleagues calculated that only meteorites heavier than about 0.15 grams could have released the water. That means the top eight centimeters or so of lunar soil are indeed dry — smaller impacts would have released water if any was there. Beneath that dry coating is a global layer of hydrated soil, with water ice clinging to dust grains.

But the moon is by no means soggy. Squeezing half a ton of lunar soil would yield barely a small bottle of water, Benna says. “It’s not a lot of water by any measure, but it’s still water.” And it’s too much water to have arrived at the moon recently, he says. The moon may have held on to at least some of this water since the time of its formation (SN: 4/15/17, p. 18).

Future studies could help figure out whether and how that water could be useful for human explorers.

The finding is “plausible and certainly provocative,” says planetary scientist Erik Asphaug of the University of Arizona in Tucson. “It’s the kind of paper that is good to see published so we can debate it.”

https://www.sciencenews.org/article/meteor-showers-dig-water-moon-nasa

 

 

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A Massive asteroid will pass closer to Earth than the Moon, Nasa warns

Anthony Cuthbertson

An asteroid purportedly the size of a 10-storey building will pass by the Earth at half the distance to the Moon, Nasa has warned.

Asteroid 2019 GC6 will pass within roughly 136,000 miles of Earth on Thursday, safely avoiding a devastating collision.

Nasa warned the orbital trajectory of the asteroid means it may still pose a risk in the future, with estimations suggesting it could be anywhere between 7.5 metres and 30 metres in length.

Shortly after it was discovered on 9 April by astronomers at the Catalina Sky Survey in Arizona, scientists at Nasa’s Jet Propulsion Laboratory in California placed it on a list of asteroids that risk colliding with Earth in the next 100 years.

It is difficult to accurately predict its exact path but it is set to pass close to the Earth again in 2034, 2041 and 2048.

It is not uncommon for rogue space debris to collide with Earth, with tons of cosmic material passing through the atmosphere every day.

The vast majority burns up before it reaches the ground, but every decade or so a larger asteroid collides with Earth.

In 2013, an asteroid 20m in diameter entered the Earth’s atmosphere over the city of Chelyabinsk in Russia, causing a massive explosion.

A subsequent study calculated it released more than 30 times the explosive energy of the Hiroshima bomb, contributing to more than 1,500 people in the local area seeking medical treatment.

“If humanity does not want to go the way of the dinosaurs, we need to study an event like this in detail,” Professor Qing-Zhu Yin of the University of California said at the time.

“Chelyabinsk serves as a unique calibration point for high-energy meteorite impact events for our future studies.”

But due to their relatively tiny size, asteroids are notoriously difficult to spot and often go undetected until a few days before they are due to pass or collide with Earth.

© Provided by Independent Digital News & Media Limited The impact site of the main mass of the Chelyabinsk meteorite in the ice of Lake Chebarkul (PA)

Astronomers at the Jet Propulsion Laboratory recently described it as like spotting a lump of coal in the night’s sky.

“Near-Earth objects [NEOs] are intrinsically faint because they are mostly really small and far away from us in space. Add to this the fact that some of them are as dark as printer toner, and trying to spot them against the black of space is very hard,” said Amy Mainzer, principal investigator of Nasa’s asteroid-hunting mission at the lab.

“If we find an object only a few days from impact, it greatly limits our choices, so in our search efforts we’ve focussed on finding NEOs when they are further away from Earth, providing a maximum amount of time and opening up a wider range of mitigation possibilities.”

https://www.msn.com/en-gb/news/techandscience/massive-asteroid-will-pass-closer-to-earth-than-the-moon-nasa-warns/ar-BBW2aAC?ocid=chromentp

 

Edited April 18, 2019 by CaaC - John

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SpaceX capsule suffers 'anomaly' during tests in Florida

SpaceX has confirmed that its Crew Dragon capsule suffered an "anomaly" during routine engine tests in Florida.

A US Air Force spokesperson told the local press the incident, at Cape Canaveral Air Force Station, had been contained and no-one had been injured.

An unmanned Crew Dragon successfully flew for the first time last month.

This latest incident, however, could delay plans to launch a manned mission to the International Space Station later this year.

Not since the end of the Space Shuttle programme in 2011 has the US been able to send its own astronauts into orbit. It has had to rely instead on Russia and its Soyuz spacecraft.

 

SpaceX, founded by Elon Musk in 2002, said it had opened an investigation and was committed to ensuring its systems met "rigorous safety standards".

Images of smoke coming from the space capsule have been circulating on social media.

https://www.bbc.co.uk/news/world-us-canada-48001382

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11 hours ago, CaaC - John said:

SpaceX capsule suffers 'anomaly' during tests in Florida

"Anomaly" is a very mild way to describe it... The capsule is completely destroyed.

That's very serious and a huge setback for their plans. Depending on the cause of the explosion, significant delays are to be expected to both the planned in-flight abort system test in July as well as the subsequent crew launch later in autumn...

[CaaC (John)+]

 

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China to build moon station in 'about 10 years'

Beijing plans to send a manned mission to the moon and to build a research station there within the next decade, state media reported Wednesday, citing a top space official.

China aims to achieve space superpower status and took a major step towards that goal when it became the first nation to land a rover on the far side of the moon in January.

It now plans to build a scientific research station on the moon's south pole within the next 10 years, China National Space Administration head Zhang Kejian said during a speech marking "Space Day", the official Xinhua news agency reported.

He also added that Beijing plans to launch a Mars probe by 2020 and confirmed that a fourth lunar probe, the Chang'e-5, will be launched by the end of the year.

Originally scheduled to collect moon samples in the second half of 2017, the Chang'e-5 was delayed after its planned carrier, the powerful Long March 5 Y2 rocket, failed during a separate launch in July 2017.

China on Wednesday also announced its Long March-5B rocket will make its maiden flight in the first half of 2020, carrying the core parts of a planned space station.

The Tiangong—or "Heavenly Palace"—will go into orbit in 2022, the China Manned Space Engineering Office said.

It is set to replace the International Space Station—a collaboration between the United States, Russia, Canada, Europe and Japan—which is due to be retired in 2024.

Beijing last week also said it would launch an asteroid exploration mission and invited collaborators to place their experiments on the probe.

The current Chang'e-4 moon lander carried equipment from Germany, the Netherlands and Sweden.

China now spends more on its civil and military space programmes than do Russia and Japan, and is second only to the United States. Although opaque, its 2017 budget was estimated at $8.4 billion by the Organization for Economic Cooperation and Development.

https://phys.org/news/2019-04-china-moon-station-years.html

 

 

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The universe is mysteriously expanding faster than scientists thought

New data gathered by NASA’s Hubble Space Telescope has reportedly widened the “mystery of the universe’s expansion rate.”

 

 

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Hayabusa-2: Spacecraft's 'bomb' crater found

The Hayabusa-2 spacecraft has sent back images of the crater made when it detonated an explosive charge next to the asteroid it is investigating.

On 5 April, the Japanese probe released a 14kg device packed with plastic explosive towards the asteroid Ryugu.

The blast drove a copper projectile into the surface, hoping to create a 10m-wide depression.

Scientists want to get a "fresh" sample of rock to help them better understand how Earth and the other planets formed.

Hayabusa-2 has now taken pictures of the area below where the "small carry-on impactor" (SCI) device was to have detonated and identified a dark disturbance in which fresh material has been excavated from beneath the surface.

Scientists working on the Japanese Aerospace Agency (Jaxa) mission said the blast area on the surface measures about 20m in diameter - twice the size of the crater they expected to see.

The mission's official account tweeted: "We did not expect such a big alteration, so a lively debate has been initiated in the project!"

Because of the debris that would have been thrown up in this event, Hayabusa-2 manoeuvred itself before the detonation to the far side of 800m-wide Ryugu - out of harm's way and out of sight.

But the probe left a small camera behind called DCAM3 to observe the explosion.

Hayabusa-2 later returned to its "home position" about 20km above the asteroid's surface. From here, it conducted a search for the crater produced in the explosion.

In coming weeks, scientists will command the probe to descend into the crater to collect its fresh samples.

Because they will come from within the asteroid, they will be less altered by the harsh environment of space.

Bombardment with cosmic radiation over the aeons is thought to change the surfaces of these planetary building blocks.

Ryugu belongs to a particularly primitive type of space rock known as a C-type asteroid. It's a relic left over from the early days of our Solar System, and therefore records the conditions and chemistry of that time - some 4.5 billion years ago.

https://www.bbc.co.uk/news/science-environment-48065282

Edited April 27, 2019 by CaaC - John

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Planetary Defense Conference 2019 has started yesterday. For those who are not sure what that is - every two years, asteroid experts from across the globe come together to pretend an asteroid impact is imminent. During these week-long impact scenarios, participants don’t know how the situation will evolve from one day to the next but must make plans based on the daily updates they are given. Very fascinating exercise to see how such a scenario could play out and ESA is covering it live this year...

This year’s asteroid – "2019 PDC"

The scene has been set for this year’s hypothetical impact scenario. Although realistic, it is completely fictional and does NOT describe an actual asteroid impact.

— An asteroid was discovered on 26 March 2019 and has been given the name “2019 PDC” by the IAU’s Minor Planet Center.

— Initial calculations suggest the orbit of 2019 PDC will bring it within 7.5 million km of Earth’s orbit. (Or, within 0.05 AU of Earth’s orbit. One AU is the mean distance between the Sun and Earth, equal to 149 597 870.7 km).— 2019 PDC is travelling in an eccentric orbit, extending 2.94 AU at its farthest point from the Sun (in the middle of the main asteroid belt), and 0.94 AU at its closest. It completes one full orbit around the Sun every 971 days (2.66 years). See its orbit in more detail here.

— The day after 2019 PDC is discovered, ESA and NASA’s impact monitoring systems identify several future dates when the asteroid could hit Earth. Both systems agree that the asteroid is most likely to strike on 29 April 2027 – more than eight years away – with a very low probability of impact of about 1 in 50 000.

— When it was first detected, asteroid 2019 PDC was about 57 million km from Earth, equal to 0.38 Astronomical Units. It was travelling about 14 km/s, and slowly getting brighter.

— As observations continue, the likelihood of an impact in 2027 increases. Three weeks after the discovery, after observations were paused during the full Moon (and reduced visibility), the chance of impact has risen to 0.4% – that’s a chance of 1 in 250.— Very little is known about the asteroid’s physical properties. From its brightness, experts determine that the asteroid’s mean size could be anywhere from 100-300 meters.

— Asteroid #2019PDC continued to approach Earth for more than a month after discovery, reaching its closest point on 13 May. Unfortunately, the asteroid was too far away to be detected, and it is not expected to pass close to Earth until 2027 – the year of impact.

— Astronomers continued to monitor the asteroid for a month after its initial detection, which provided them with more information about the object’s trajectory, and have now discovered that the chance of impact is rapidly increasing. By 29 April 2019, (the first day of the Planetary Defence Conference), the probability of impact has risen to 1 in 100.

Day 1:

Asteroid impact chance 1 in 100.

Day 2:

Four months after asteroid 2019 PDC is detected, observations now show the chance of Earth impact has increased to 1 in 10.

All the live updates here on ESA's twitter... https://twitter.com/esaoperations

Or the website: https://blogs.esa.int/rocketscience/2019/04/25/hypothetical_impact/

 

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Nasa instrument heads to space station to map CO2

Nasa has sent up an instrument to the International Space Station (ISS) to help track carbon dioxide on Earth.

OCO-3, as the observer is called, was launched on a Falcon rocket from Florida in the early hours of Saturday.

The instrument is made from the spare components left over after the assembly of a satellite, OCO-2, which was put in orbit to do the same job in 2014.

The data from two missions should give scientists a clearer idea of how CO2 moves through the atmosphere.

One way this will be achieved is through the different perspectives OCO-2 and OCO-3 will get.

The former flies around the entire globe in what's termed a sun-synchronous polar orbit, which leads to it seeing any given location at the same time of day.

The latter, on the other hand, because it will fly aboard the station, will only see locations up to 51 degrees North and South; and see them at many different times of the day.

That's interesting because plants' ability to absorb CO2 varies during the course of daylight hours. OCO-3's dataset will, therefore, have much to add to that of its predecessor.

"Getting this different time of day information from the orbit of the space station is going to be really valuable," Nasa project scientist Dr Annmarie Eldering told BBC News.

"We have a lot of good arguments about diurnal variability: plants' performance over different times of day; what possibly could we learn? So, I think that's going to be exciting scientifically."

The Orbiting Carbon Observatory (OCO) missions are trying to tie down the uncertainties in the cycling of CO2 - how and where the greenhouse gas is emitted (sources), versus how and where it's absorbed (sinks).

Humans are driving an imbalance in this cycle, increasing the concentration of the gas in the air.

Currently, anthropogenic activities pump out just under 40 billion tonnes of CO2 year-on-year, principally from the burning of fossil fuels.

Only about half of this sum stays in the atmosphere, where it adds to warming

About half of the other half is absorbed into the ocean, with the remainder pulled down into land "sinks". But these "budgets" are imperfectly characterised. Some sizeable sources and sinks - both human and natural - need a fuller description.

The OCO instruments incorporate spectrometers that break the sunlight reflected off the Earth's surface into its constituent colours, and then analyse the spectrum to determine how much carbon dioxide is present.

The analysis of the data is complex because it requires the use of models to explain how the gas is mixed through the atmosphere.

The space station instrument brings a new trick to the OCO observations - a swivelling mirror system that allows the spectrometer system to scan a much wider swath of the Earth's surface than would ordinarily be the case.

This snapshot mode means CO2 maps can be built up in a single pass over a target of special interest such as a megacity - a task that will take OCO-2 several days.

"The snapshot mode allows us to grab snippets of data over an area of about 80km by 80km in two minutes. Right now we think we may spend about a quarter of our time making these mini maps, up to 100 a day," Dr Eldering said.

OCO-3 will be positioned on the Japanese segment of the space station. Its mission lifetime is pretty fixed at three years, therefore. That's because the berth it is taking up on the observation platform is already booked for a future instrument.

Carbon monitoring will, however, see many more satellite systems launched in the coming years.

Europe is planning a constellation of observers in its Sentinel series that will map CO2 over a much wider area than OCO, but still with the same high precision.

This orbiting network would even make it possible to police individual countries' commitments to reduce carbon emissions under international agreements such as the Paris climate accord of 2015.

https://www.bbc.co.uk/news/science-environment-48150645

Edited May 4, 2019 by CaaC - John
Spelling correction

[CaaC (John)+]

Coolest space discoveries

Time and again, we have made some of the most amazing discoveries, from the Pillars of Creation to the first asteroid. Let's have a look at some of those discoveries. 

1-14 Slides

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A commercial resupply mission heads to the space station, watching Earth breathe from space, and dealing with the impact threat of near-Earth objects … a few of the stories to tell you about – This Week at NASA!

 

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[CaaC (John)+]

NASA's Fermi Satellite Clocks a 'Cannonball' Pulsar

Astronomers using NASA's Fermi Gamma-ray Space Space Telescope and the National Science Foundation's Karl G. Jansky Very Large Array (VLA) have found a pulsar hurtling through space at nearly 2.5 million miles an hour -- so fast it could travel the distance between Earth and the Moon in just 6 minutes. Pulsars are super dense, rapidly spinning neutron stars left behind when a massive star explodes. This one, dubbed PSR J0002+6216 (J0002 for short), sports a radio-emitting tail pointing directly toward the expanding debris from a recent supernova explosion. Thanks to its narrow dart-like tail and a fortuitous viewing angle, astronomers can trace this pulsar straight back to its birthplace. Further study of J0002 will help us better understand how these explosions are able to 'kick' neutron stars to such high speed. The pulsar is located about 6,500 light-years away in the constellation Cassiopeia. It was discovered in 2017 by a citizen-science project called Einstein@Home , which uses downtime on the computers of volunteers to process Fermi gamma-ray data and has identified 23 gamma-ray pulsars to date. J0002 spins 8.7 times a second, producing a pulse of gamma rays with each rotation, and has about 1.5 times the mass of the Sun. The pulsar lies about 53 light-years from the centre of a supernova remnant called CTB 1. Its rapid motion through interstellar gas results in shock waves that produce the tail of magnetic energy and accelerated particles detected at radio wavelengths using the VLA. The tail extends 13 light-years and clearly points back to the centre of CTB 1. Using Fermi data and a technique called pulsar timing, the team was able to measure how quickly and in what direction the pulsar was moving across our line of sight thanks to Fermi's 10-year data covering the entire sky. J0002 is speeding through space five times faster than the average pulsar and faster than 99 per cent of those with measured speeds. It will eventually escape our galaxy.

https://www.nasa.gov/topics/solarsystem/videos/index.html

Edited May 8, 2019 by CaaC - John

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Algae 'Bioreactor' on Space Station Could Make Oxygen, Food for Astronauts

Astronauts on the International Space Station will begin testing an innovative algae-powered bioreactor to assess its feasibility for future long-duration space missions. 

The algae-powered bioreactor, called the Photobioreactor, represents a major step toward creating a closed-loop life-support system, which could one day sustain astronauts without cargo resupply missions from Earth. This will be particularly important for future long-duration missions to the moon or Mars, which require more supplies than a spacecraft can carry, according to a statement from the German Aerospace Center (DLR). 

The Photobioreactor arrived at the space station Monday (May 6) on a SpaceX Dragon cargo ship. The experiment is designed to use algae to convert the carbon dioxide exhaled by astronauts on the space station into oxygen and edible biomass through photosynthesis.

The experiment will cultivate microscopic algae called Chlorella vulgaris aboard the space station. In addition to producing oxygen, the algae also produce a nutritional biomass that astronauts could eat. 

Creating an edible biomass from carbon dioxide within the spacecraft means less food would need to be transported or delivered on space missions. The researchers estimate roughly 30 percent of an astronaut's food could be replaced by algae due to its high protein content, according to the statement.

https://www.space.com/space-station-algae-experiment-fresh-air.html

Straight out of sci-fi.

[CaaC (John)+]

41 minutes ago, nudge said:

Straight out of sci-fi.

Give me more    

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Bizarre form of hot ice seen on Earth

Adam Mann

 

Watch: Neptune 101 (National Geographic)

From the seas of Antarctica to the depths of your freezer, most ice on Earth is relatively tame stuff. But throughout the solar system and beyond, extreme temperatures and pressures can crush the frozen substance into increasingly odd varieties.

Now, researchers have snapped x-ray images of what might be the newest entrant to ice’s diversity: a highly electrically conductive material known as superionic ice. As the team reports today in the journal Nature, this ice exists at pressures between one and four million times that at sea level and temperatures half as hot as the surface of the sun.

© Illustration by Millot, Coppari, Hamel, Krauss (LLNL)

From left to right in this artistic rendering, high-power lasers focus on the surface of a diamond, generating a sequence of shock waves that propagate through a sample of water, simultaneously compressing and heating the initially liquid sample and forcing it to freeze into superionic ice.

“Yes, we’re talking about ice,” says study leader Marius Millot, a physicist at Lawrence Livermore National Laboratory in California. “But the sample is at several thousand degrees.”

While normally unachievable on Earth, such conditions should be present deep inside the watery giants Uranus and Neptune, potentially helping to explain how these distant planets work, including the origins of their unusual magnetic fields.

Beyond Vonnegut

Scientists already know of 17 varieties of crystalline ice (fans of Kurt Vonnegut might be relieved to know that Ice IX is quite innocuous compared to its fictional counterpart). And more than 30 years ago, physicists predicted that crushing pressure should squeeze water into superionic forms.

Superionic materials are dual beasts, part solid and part liquid, that on a microscopic level consist of a crystal lattice permeated by free-floating atomic nuclei that can carry an electrical charge. In water—aka H2O—the oxygen atoms would crunch into a solidified crystal while the hydrogen’s protons would zip around like a liquid. (Recently, another team of scientists working with potassium confirmed the existence of a state of matter that is solid and liquid at the same time.)

“It’s quite an exotic state of matter,” says coauthor Federica Coppari, also of the Livermore lab.

Last year, Millot, Coppari, and their colleagues found the first evidence for superionic ice, using diamond anvils and laser-induced shock waves to compress liquid water so much that it turned to solid ice for a few billionths of a second. The team’s measurements showed that the water ice briefly became hundreds of times more electrically conductive than it had previously been, a strong hint that it had gone supersonic.

© Photograph by Millot, Coppari, Kowaluk (LLNL)

In this time-integrated photograph of an x-ray diffraction experiment, giant lasers focus on the water sample, which is sitting on the front plate of the diagnostic tool used to record diffraction patterns. Additional laser beams generate an x-ray flash off an iron foil, which allows the researchers to take a snapshot of the compressed and heated water layer.

In their latest tests, the researchers used six giant laser beams to generate a sequence of shockwaves that crunched a thin layer of liquid water into solidified ice at millions of times Earth’s surface pressure and between 3,000 and 5,000 degrees Fahrenheit. Precisely timed x-ray flashes probed the configuration, which again only lasted for a few billionths of a second, and revealed that the oxygen atoms had indeed taken on a crystalline form.

The oxygen was seen to be tightly packed into face-centred cubes—little boxes with an atom at each corner and one in the middle of each side. This is the first time that water ice has been seen taking on such an arrangement, Coppari says. The team has proposed calling this new formation Ice XVIII.

While there was some overlap in conditions between the team’s two experiments, more investigations will be necessary to definitively prove that the ice is superionic, says Roberto Car, a Princeton University physicist who was not involved in the work. Nevertheless, he considers the study to be an important illustration of water’s variableness.

“The fact that matter can arrange itself in such a large variety of forms is quite astonishing,” he says.

Magnetic mysteries

The team’s results are already informing models of Uranus and Neptune. Often known as ice giants, these enormous worlds are around 65 per cent water, plus some ammonia and methane, which forms layers much like the rocky-metallic surface, mantle, and core of Earth.

The new experiments indicate that Uranus and Neptune should have a superionic ice layer that acts like our planet’s mantle, which is made of solid rock that still flows on extremely long geological timescales. And that could help explain why they have unusual magnetic fields.

The magnetic fields of Earth, Jupiter, and Saturn are all thought to be created by internal dynamos near their cores. These planets’ fields are aligned fairly closely with their axes as if they are coming from bar magnets sticking through the planets’ centres. (Here’s what happened when scientists had to update our best map of Earth’s magnetic field.)

Neptune’s magnetic field, by contrast, seems to come from an internal bar magnet that has drifted down to one side, with its ends emerging from spots halfway to the equator. Uranus’ is even more outlandish, like a bar magnet that has flipped upside-down, meaning its magnetic south juts out from the planet’s northern hemisphere. Both ice giants’ magnetic fields are suspected of being unstable.

Millot has suggested that there could be a liquid layer at the top edge of Uranus and Neptune’s superionic ice layer, but that it is also a highly electrically conductive phase of water. The planets’ magnetic fields might originate here, far closer to the surface than the magnetic fields of other worlds, potentially explaining their wonky characteristics. And since astronomers have discovered many Neptune and Uranus-sized exoplanets, the findings could be applicable to far-flung parts of the cosmos.

https://www.msn.com/en-gb/news/techandscience/bizarre-form-of-hot-ice-seen-on-earth/ar-AAB7Hoe?ocid=chromentp

 

Edited May 9, 2019 by CaaC - John
Spelling corrections

[CaaC (John)+]

May 10, 2019

Hubble Peers at an Ancient Galaxy Cluster

Dotted across the sky in the constellation of Pictor (the Painter’s Easel) is the galaxy cluster highlighted here by the NASA/ESA Hubble Space Telescope: SPT-CL J0615-5746, or SPT0615 for short.

SPT0615, first discovered by the South Pole Telescope less than a decade ago, is a massive cluster of galaxies, one of the farthest observed to cause gravitational lensing. Gravitational lensing occurs when light from a background object is deflected around mass between the object and the observer. Among the identified background objects, there is SPT0615-JD, a galaxy that is thought to have emerged just 500 million years after the big bang. This puts it among the very earliest structures to form in the universe. It is also the farthest galaxy ever imaged by means of gravitational lensing.

Just as ancient paintings can tell us about the period of history in which they were painted, so too can ancient galaxies tell us about the era of the universe in which they existed. To learn about cosmological history, astronomers explore the most distant reaches of the universe, probing ever further out into the cosmos. The light from distant objects travels to us from so far away that it takes an immensely long time to reach us, meaning that it carries information from the past — information about the time at which it was emitted.

By studying such distant objects, astronomers are continuing to fill the gaps in our picture of what the very early universe looked like, and uncover more about how it evolved into its current state.

Text credit: ESA (European Space Agency)
Image credit: ESA/Hubble & NASA, I. Karachentsev et al., F. High et al. 

Last Updated: May 10, 2019

Editor: Rob Garner

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May 13, 2019

RELEASE 19-06

Shrinking Moon May Be Generating Moonquakes

The Moon is shrinking as its interior cools, getting more than about 150 feet (50 meters) skinnier over the last several hundred million years. Just as a grape wrinkles as it shrinks down to a raisin, the Moon gets wrinkles as it shrinks. Unlike the flexible skin on a grape, the Moon’s surface crust is brittle, so it breaks as the Moon shrinks, forming “thrust faults” where one section of crust is pushed up over a neighbouring part.

“Our analysis gives the first evidence that these faults are still active and likely producing moonquakes today as the Moon continues to gradually cool and shrink,” said Thomas Watters, senior scientist in the Center for Earth and Planetary Studies at the Smithsonian’s National Air and Space Museum in Washington. “Some of these quakes can be fairly strong, around five on the Richter scale.”

This visualization of Lee Lincoln scarp is created from Lunar Reconnaissance Orbiter photographs and elevation mapping. The scarp is a low ridge or step about 80 meters high and running north-south through the western end of the Taurus-Littrow valley, the site of the Apollo 17 Moon landing. The scarp marks the location of a relatively young, low-angle thrust fault. The land west of the fault was forced up and over the eastern side as the lunar crust contracted. In a May 2019 paper published in Nature Geoscience, Thomas Watters and his coauthors provide evidence that this fault and others like it are still active and producing moonquakes today.

Credits: NASA/Goddard/SVS/Ernie Wright

 

MORE >> https://www.nasa.gov/press-release/goddard/2019/moonquakes

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Chang'e-4: Chinese rover 'confirms' Moon crater theory

The Chinese Chang'e-4 rover may have confirmed a longstanding idea about the origin of a vast crater on the Moon's far side.

The rover's landing site lies within a vast impact depression created by an asteroid strike billions of years ago.

Now, mission scientists have found evidence that impact was so powerful it punched through the Moon's crust and into the layer below called the mantle.

Chang'e-4 has identified what appear to be mantle rocks on the surface.

It's something the rover was sent to the far side to find out.

Chunlai Li, from the Chinese Academy of Sciences in Beijing, and colleagues have presented their findings in the journal Nature.

The lunar far side, which is turned away from Earth, is more rugged than the familiar near side and has fewer "maria" - dark plains formed by ancient volcanic eruptions.

The Chinese spacecraft touched down on 3 January, becoming the first spacecraft to perform a soft landing on the lunar far side. The rover then rolled off the lander to explore its surroundings.

The rover landed inside a 180km-wide impact bowl called Von Kármán crater. But that smaller crater lies within the 2,300km-wide South Pole Aitken (SPA) Basin, which covers nearly a quarter of the Moon's circumference.

It's not known exactly how old the SPA Basin is, but it's thought to be at least 3.9 billion years old. The asteroid that carved it out is thought to have been about 170km wide.

The Yutu-2 rover has now identified rocks with a very different chemical make-up to those found elsewhere on the Moon.

Early results from the rover's Visible and Near Infrared Spectrometer (VNIS) suggest the rocks contain minerals known as low-calcium (ortho)pyroxene and olivine.

They fit the profile of rocks from the lunar mantle and suggest that the ancient impact that created the SPA drove right through the 50km-deep crust into the mantle.

Observational data taken by Moon-orbiting spacecraft have been inconclusive as to the presence of mantle rocks on the surface.

The authors of the paper want to continue their examination of these rocks and find others. They have also raised the possibility of sending another mission to deliver some of them to Earth for study in laboratories.

The results could now help scientists understand the chemical and mineralogical composition of the mantle, which could shed light on the origins and evolution of the Moon itself.

The team members also want to find out more about what happened after the asteroid collided with the Moon and formed the SPA Basin. Scientists predict that the hole in the surface may have been filled by molten rock - forming a "melt sheet" within the impact bowl, which complicates the picture of this region's geology.

Patrick Pinet, from the Research Institute in Astrophysics and Planetology (IRAP) in Toulouse, France, called the results "thrilling" and said they "could have considerable implications for characterising the composition of the Moon's upper mantle".

He added: "It is of the utmost importance to make progress towards unpacking the geology of the lunar far side, expanding our fundamental knowledge of the Moon's formation and the origin of the crustal asymmetry that exists between its near and far sides, and preparing future sample-return missions."

https://www.bbc.co.uk/news/science-environment-48285503

[CaaC (John)+]

Something Appears to Have Ripped a Massive Hole in the Milky Way's Edge

Hannah Osborne

Something appears to have torn a hole in part of the Milky Way’s halo. The “dark substructure” was found via Gaia observations—a project set out to produce the most detailed 3D map of our galaxy—with Harvard scientist Ana Bonaca noticing a perturbation in a tidal stream.

She presented her findings at the American Physical Society’s April meeting.

As first reported by LiveScience, Bonaca was focusing on tidal streams produced by stars escaping from globular clusters—normally found at the edges of a galaxy. The stellar halo of the Milky Way is full of these tidal streams.

If there is nothing to disturb them, the streams are almost uniform in terms of their density. However, Bonaca noticed there was a hole in one. “The on-sky morphology suggests a recent, close encounter with a massive and dense perturber,” an abstract to her work reported.

What this “perturber” is, however, is unknown. "It's a dense bullet of something," Bonaca told LiveScience. Telescopes failed to find the source—so what could it be?

The hole is enormous, so whatever made it must also have been. "It's much more massive than a star,” she told the website. “Something like a million times the mass of the sun. So there are just no stars of that mass. We can rule that out. And if it were a black hole, it would be a supermassive black hole of the kind we find at the centre of our own galaxy."

The problem with this idea is that there are no signs of a supermassive black hole in the vicinity.

At the moment, observations do not show any large luminous object (something made from ordinary matter, which reflects light) moving away from the hole. This led Bonaca to suggest the perturbation could have been made by dark matter. This is the mystery substance that makes up about 27 per cent of the universe. Scientists know it is there because of the gravitational force it exerts on normal matter—but because it is “dark” in that it does not reflect light, and so we cannot see what it is.

“Observations permit a low-mass dark-matter subhalo as a plausible candidate,” Bonaca’s abstract says.

This dense blob of dark matter could have smashed through the tidal stream—if this is what caused the hole—and would be an exciting find for scientists, as it would provide them the opportunity of studying this elusive substance. The discovery of a dark matter “bullet” would also fit with current predictions about what dark matter is like—research suggests it is “clumpy,” in that it is not smooth and evenly distributed around the universe.

Identifying a clump of dark matter “opens up the possibility that detailed observations of streams could measure the mass spectrum of dark-matter substructures and even identify individual substructures,” her abstract concludes.

However, she says this still does not rule out a luminous object. "It could be that it's a luminous object that went away somewhere, and it's hiding somewhere in the galaxy," she said.

Bocana’s research is still in the early stages. She is yet to publish her findings in a peer-reviewed journal—however, LiveScience reports her presentation was welcomed by attendees.

https://www.msn.com/en-gb/news/spotlight/something-appears-to-have-ripped-a-massive-hole-in-the-milky-ways-edge/ar-AABAly4?ocid=chromentp

[CaaC (John)+]

May 16, 2019

Galaxy Blazes With New Stars Born From Close Encounter

The irregular galaxy NGC 4485 shows all the signs of having been involved in a hit-and-run accident with a bypassing galaxy. Rather than destroying the galaxy, the chance encounter is spawning a new generation of stars, and presumably planets.

The right side of the galaxy is ablaze with star formation, shown in the plethora of young blue stars and star-incubating pinkish nebulas. The left side, however, looks intact. It contains hints of the galaxy’s previous spiral structure, which, at one time, was undergoing normal galactic evolution.

The larger culprit galaxy, NGC 4490, is off the bottom of the frame. The two galaxies sideswiped each other millions of years ago and are now 24,000 light-years apart. The gravitational tug-of-war between them created rippling patches of higher-density gas and dust within both galaxies. This activity triggered a flurry of star formation.

This galaxy is a nearby example of the kind of cosmic bumper-car activity that was more common billions of years ago when the universe was smaller and galaxies were closer together.

NGC 4485 lies 25 million light-years away in the northern constellation Canes Venatici (the Hunting Dogs).

This new image, captured by Hubble’s Wide Field Camera 3 (WFC3), provides further insight into the complexities of galaxy evolution.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

Text credit: Space Telescope Science Institute
Image credit: NASA, ESA; acknowledgement: T. Roberts (Durham University, UK), D. Calzetti (University of Massachusetts) and the LEGUS Team, R. Tully (University of Hawaii) and R. Chandar (University of Toledo)

Last Updated: May 16, 2019

Editor: Rob Garner

https://www.nasa.gov/image-feature/goddard/2019/galaxy-blazes-with-new-stars-born-from-close-encounter

[nudge]

With the NASA's Mars 2020 Rover mission slowly approaching, you can now submit your name to be sent to Mars... All submitted names are reviewed, approved and then etched onto a microchip. The microchip is placed aboard the Mars 2020 rover, which will land on Mars. 

https://mars.nasa.gov/participate/send-your-name/mars2020

Pretty cool!

[CaaC (John)+]

On 22/05/2019 at 22:38, nudge said:

With the NASA's Mars 2020 Rover mission slowly approaching, you can now submit your name to be sent to Mars... All submitted names are reviewed, approved and then etched onto a microchip. The microchip is placed aboard the Mars 2020 rover, which will land on Mars. 

https://mars.nasa.gov/participate/send-your-name/mars2020

Pretty cool!

All done!!!! WEEEEEEEEEE I could be off to Mars    

 

Edited May 24, 2019 by CaaC - John
Spacing correction

[CaaC (John)+]

May 20, 2019

NASA's Juno Finds Changes in Jupiter's Magnetic Field

This still from an animation illustrates Jupiter's magnetic field at a single moment in time. The Great Blue Spot, an-invisible-to-the-eye concentration of magnetic field near the equator, stands out as a particularly strong feature.

Credits: NASA/JPL-Caltech/Harvard/Moore et al.

Full image and caption

NASA's Juno mission to Jupiter made the first definitive detection beyond our world of an internal magnetic field that changes over time, a phenomenon called secular variation. Juno determined the gas giant's secular variation is most likely driven by the planet's deep atmospheric winds.

The discovery will help scientists further understand Jupiter's interior structure — including atmospheric dynamics — as well as changes in Earth's magnetic field. A paper on the discovery was published today in the journal Nature Astronomy.

"Secular variation has been on the wish list of planetary scientists for decades," said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. "This discovery could only take place due to Juno's extremely accurate science instruments and the unique nature of Juno's orbit, which carries it low over the planet as it travels from pole to pole."

Characterizing the magnetic field of a planet requires close-up measurements. Juno scientists compared data from NASA's past missions to Jupiter (Pioneer 10 and 11, Voyager 1 and Ulysses) to a new model of Jupiter's magnetic field (called JRM09). The new model was based on data collected during Juno's first eight science passes of Jupiter using its magnetometer, an instrument capable of generating a detailed three-dimensional map of the magnetic field.

This striking view of Jupiter's Great Red Spot and turbulent southern hemisphere was captured by NASA's Juno spacecraft as it performed a close pass of the gas giant planet.

Credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill

Full image and caption

What scientists found is that from the first Jupiter magnetic field data provided by the Pioneer spacecraft through to the latest data provided by Juno, there were small but distinct changes to the field.

"Finding something as minute as these changes in something so immense as Jupiter's magnetic field was a challenge," said Kimee Moore, a Juno scientist from Harvard University in Cambridge, Massachusetts. "Having a baseline of close-up observations over four decades long provided us with just enough data to confirm that Jupiter's magnetic field does indeed change over time."

Once the Juno team proved secular variation did occur, they sought to explain how such a change might come about. The operation of Jupiter's atmospheric (or zonal) winds best explained the changes in its magnetic field. These winds extend from the planet's surface to over 1,860 miles (3,000 kilometers) deep, where the planet's interior begins changing from gas to highly conductive liquid metal. They are believed to shear the magnetic fields, stretching them and carrying them around the planet.

Nowhere was Jupiter's secular variation as large as at the planet's Great Blue Spot, an intense patch of magnetic field near Jupiter's equator. The combination of the Great Blue Spot, with its strong localized magnetic fields, and strong zonal winds at this latitude result in the largest secular variations in the field on the Jovian world.

"It is incredible that one narrow magnetic hot spot, the Great Blue Spot, could be responsible for almost all of Jupiter's secular variation, but the numbers bear it out," said Moore. "With this new understanding of magnetic fields, during future science passes we will begin to create a planetwide map of Jupiter's secular variation. It may also have applications for scientists studying Earth's magnetic field, which still contains many mysteries to be solved."

NASA's JPL manages and operates the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA's New Frontiers Program, which is managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the agency's Science Mission Directorate. The Italian Space Agency (ASI) contributed two instruments, a Ka-band frequency translator (KaT) and the Jovian Infrared Auroral Mapper (JIRAM). Lockheed Martin Space in Denver built and operates the spacecraft.

https://www.nasa.gov/feature/jpl/nasas-juno-finds-changes-in-jupiters-magnetic-field