Top News

Milky Way could have 100 billion brown dwarfs

LHCb experiment announces observation of a new particle with two heavy quarks

Recreating interstellar ions with lasers

Study finds Earth’s mag-netic field ‘simpler than we thought’

The spin in graphene can be switched off

A future without fakes thanks to quantum technol-ogy

Preparing for Mercury: Bep-iColombo stack completes testing

Gaia Finds Six Stars Zipping out of the Milky Way

Physicists provide support for retrocausal quantum the-ory, in which the future influ-ences the past

Physicists read Maxwell’s De-mon’s mind

Scientists get first direct look at how electrons ‘dance’ with vibrating atoms

Mars surface ‘more uninhab-itable’ than thought: study

This Week’s Sky at a Glance, July 08-14, 2017

July 08, 2017 Shawwal 14, 1438 AH Volume 7, Issue 27

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Special Read:

NASA’S First Asteroid Deflec-tion Mission Enters Next De-sign Phase

SCASS Summer Camp - July 09-12, 2017

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Milky Way could have 100 billion brown dwarfs

RCW 38 is 5500 light years away, meaning that the brown dwarfs are both faint, and hard to pick out next to the brighter stars. To get a clear image, Scholz, Muzic and their collaborators used the NACO adaptive optics camera on the European South-ern Observatory’s Very Large Telescope, observing the cluster for a total of 3 hours, and combining this with earlier work. (illustration only)

Our galaxy could have 100 billion brown dwarfs or more, according to work by an international team of astrono-mers, led by Koraljka Muzic from the University of Lisbon and Aleks Scholz from the University of St Andrews. On Thursday 6 July Scholz will present their survey of dense star clusters, where brown dwarfs are abundant, at the Na-tional Astronomy Meeting at the University of Hull.

Brown dwarfs are objects intermediate in mass between stars and planets, with masses too low to sustain stable hydrogen fusion in their core, the hallmark of stars like the Sun. After the initial discovery of brown dwarfs in 1995, scientists quickly realised that they are a natural by-prod-uct of processes that primarily lead to the formation of stars and planets.

All of the thousands of brown dwarfs found so far are rel-atively close to the Sun, the overwhelming majority within 1500 light years, simply because these objects are faint and therefore difficult to observe. Most of those detected are located in nearby star forming regions, which are all fairly small and have a low density of stars.

In 2006 the team began a new search for brown dwarfs, observing five nearby star forming regions. The Substellar Objects in Nearby Young Clusters (SONYC) survey includ-ed the star cluster NGC 1333, 1000 light years away in the constellation of Perseus. That object had about half as many brown dwarfs as stars, a higher proportion than seen before.

To establish whether NGC 1333 was unusual, in 2016 the team turned to another more distant star cluster, RCW 38, in the constellation of Vela. This has a high density of more massive stars, and very different conditions to other clusters. RCW 38 is 5500 light years away, meaning that the brown dwarfs are both faint, and hard to pick out next to the brighter stars. To get a clear image, ....Read More...

LHCb experiment announces observation of a new particle with two heavy quarks

Credit: CERN

Today at the EPS Conference on High Energy Physics in Venice, the LHCb experiment at CERN’s Large Hadron Collider has reported the observation of Ξcc++ (Xicc++) a new particle containing two charm quarks and one up quark. The existence of this particle from the baryon fam-ily was expected by current theories, but physicists have been looking for such baryons with two heavy quarks for many years. The mass of the newly identified particle is about 3621 MeV, which is almost four times heavier than the most familiar baryon, the proton, a property that arises from its doubly charmed quark content. It is the first time that such a particle has been unambiguously detected.

Nearly all the matter that we see around us is made of baryons, which are common particles composed of three quarks, the best-known being protons and neutrons. But there are six types of existing quarks, and theoretically many different potential combinations could form other kinds of baryons. Baryons so far observed are all made of, at most, one heavy quark.

“Finding a doubly heavy-quark baryon is of great interest as it will provide a unique tool to further probe quantum chromodynamics, the theory that describes the strong interaction, one of the four fundamental forces,” said Giovanni Passaleva, new Spokesperson of the LHCb col-laboration. “Such particles will thus help us improve the predictive power of our theories.”

“In contrast to other baryons, in which the three quarks perform an elaborate dance around each other, a doubly heavy baryon is expected to act like a planetary system, where the two heavy quarks play the role of heavy stars orbiting one around the other, with the lighter quark orbiting around this binary system,” added Guy Wilkinson, former Spokesperson of the collaboration.

Measuring the properties of the Ξcc++ will help to estab-lish how a system of two heavy quarks and a light quark behaves. Important insights can be obtained by precisely measuring production and decay mechanisms, and the lifetime of this new particle. ...Read More...

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Recreating interstellar ions with lasers

MSU’s Marcos Dantus has recreated interstellar ions with lasers. Credit Courtesy of MSU

Trihydrogen, or H3+, has been called the molecule that made the universe, where it plays a greater role in astro-chemistry than any other molecule.

While H3+ is astronomically abundant, no scientist under-stood the mechanisms that form it from organic molecules.Until now.

Using lasers, Michigan State University scientists have unlocked the secret and published their results in the cur-rent issue of Scientific Reports. In a basement laboratory on campus, Marcos Dantus, University Distinguished Pro-fessor in chemistry and physics, and his team essentially duplicated the mechanism that’s found from the center of the galaxy to Earth’s own ionosphere.

The scientists found H3+ when they used a strong-field laser to initiate a reaction and a second femtosecond la-ser to probe its progress. These interactions often lead to exotic chemical reactions. In this case, it unexpectedly re-vealed the phantom mechanisms of H3+.

“We found that a roaming H2 molecule is responsible for the chemical reaction, producing H3+; roaming chemistry is extremely new and little is known about it,” Dantus said. “This is the first documented case for a roaming H2 re-action, which is significant because roaming mechanisms are a budding chapter of chemistry - one that may provide explanations for unlikely and unexplained chemical reac-tions.”

One reason for the dearth of knowledge is that the pro-cess happens in near immeasurable time. The entire reac-tion, involving cleavage and formation of three chemical bonds, takes between 100 or 240 femtoseconds. That’s less time than it takes a bullet to travel the width of an atom, Dantus added.

How the roaming H2 molecule extracts the proton to evolve to H3+ is nothing short of astounding, according to the scientists. A neutral H2 molecule is formed upon ionization of an organic molecule, and it ..Read More...

Study finds Earth’s mag-netic field ‘simpler than we thought’

File Image.

Scientists have identified patterns in the Earth’s magnetic field that evolve on the order of 1,000 years, providing new insight into how the field works and adding a mea-sure of predictability to changes in the field not previously known.

The discovery also will allow researchers to study the planet’s past with finer resolution by using this geomag-netic “fingerprint” to compare sediment cores taken from the Atlantic and Pacific oceans.

Results of the research, which was supported by the National Science Foundation, were recently published in Earth and Planetary Science Letters.

The geomagnetic field is critical to life on Earth. Without it, charged particles from the sun (the “solar wind”) would blow away the atmosphere, scientists say. The field also aids in human navigation and animal migrations in ways scientists are only beginning to understand. Centuries of human observation, as well as the geologic record, show our field changes dramatically in its strength and structure over time.

Yet in spite of its importance, many questions remain un-answered about why and how these changes occur. The simplest form of magnetic field comes from a dipole: a pair of equally and oppositely charged poles, like a bar magnet.“We’ve known for some time that the Earth is not a perfect dipole, and we can see these imperfections in the histor-ical record,” said Maureen “Mo” Walczak, a post-doctoral researcher at Oregon State University and lead author on the study. “We are finding that non-dipolar structures are not evanescent, unpredictable things. They are very long-lived, recurring over 10,000 years - persistent in their lo-cation throughout the Holocene.

“This is something of a Holy Grail discovery,” she added, “though it is not perfect. It is an important first step in bet-ter understanding the magnetic field, and synchronizing sediment core data at a finer scale.” ...Read More...

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The spin in graphene can be switched off

The experiment setup consists of a heterostructure of graphene and molybdenum disulphide; a spintronic device. By applying a gate voltage, it is possible to control whether the current that passes will include any spin signal or not. Credit: Chalmers Uni-versity of Technology

By combining graphene with another two-dimensional material, researchers at Chalmers University of Technolo-gy have created a prototype of a transistor-like device for future computers, based on what is known as spintronics. Spin as the information carrier can result in electronics that are significantly faster and more energy efficient. It can also lead to more versatile components capable of both data calculation and storage. The discovery is pub-lished in the scientific journal Nature Communications.

Just over two years ago, the same research group at Chalm-ers University of Technology demonstrated that graphene, which is an excellent electrical conductor, also has unsur-passed spintronic properties.

The super-thin carbon mesh proved capable of convey-ing electrons with coordinated spin over longer distances and preserving the spin for a longer time than any other known material at room temperature.

Although the distance is still on the scale of a few mi-crometres and the time is still measured in nanoseconds, this in principle opened the door to the possibility of using spin in microelectronic components.

“But, it is not enough to have a good motorway for the spin signal to travel on. You also need traffic lights so the signal can be controlled,” says Associate Professor Saroj Dash, leader of the research group.

“Our new challenge became finding a material that can both convey and control the spin. It is hard, since both tasks normally require completely opposite material prop-erties,” he explains.

Like many other researchers in the hot field of graphene, the Chalmers researchers therefore chose to test a com-bination of graphene and another thin, so-called two-di-mensional material, with contrasting spintronic properties. “Our material of choice was molybdenum disulphide, MoS2, due to its low spin lifetime steaming from high spin-orbit coupling,” states André Dankert, postdoc...Read More...

A future without fakes thanks to quantum technology

Gold microchip. Credit: Lancaster University

Counterfeit products are a huge problem - from medicines to car parts, fake technology costs lives.

Every year, imports of counterfeited and pirated goods around the world cost nearly US $0.5 trillion in lost rev-enue.

Counterfeit medicines alone cost the industry over US $200 billion every year. They are also dangerous to our health – around a third contain no active ingredients, re-sulting in a million deaths a year.

And as the Internet of Things expands, there is the need to trust the identity of smart systems, such as the brake system components within connected and driverless cars.

But researchers exhibiting at the Royal Society Summer Science Exhibition believe we are on the verge of a future without fakes thanks to new quantum technology.

Whether aerospace parts or luxury goods, the researchers say the new technology will make counterfeiting impos-sible.

Scientists have created unique atomic-scale ID’s based on the irregularities found in 2-D materials like graphene.

On an atomic scale, quantum physics amplifies these irreg-ularities, making it possible to ‘fingerprint’ them in simple electronic devices and optical tags.

The team from Lancaster University and spin-out compa-ny Quantum Base will be announcing their new patent in optical technology to read these imperfections at the “Fu-ture without Fakes” exhibit of the Royal Society’s Summer Science Exhibition.

For the first time, the team will be showcasing this new technology via a smartphone app which can read whether a product is real or fake, and enable people to check the authenticity of a product through their smartphones. The customer will be able to scan the optical tag on a product with a smartphone, which will match the 2-D tag with the manufacturer’s database. ..Read More...

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Preparing for Mercury: Bep-iColombo stack completes testing

The final ‘qualification and acceptance review’ of the mission is foreseen for early March. Then BepiColombo will be flown to Europe’s Spaceport in Kourou, French Guiana, in preparation for the October 2018 departure window. The date will be confirmed later this year.

ESA’s Mercury spacecraft has passed its final test in launch configuration, the last time it will be stacked like this be-fore being reassembled at the launch site next year.

BepiColombo’s two orbiters, Japan’s Mercury Magneto-spheric Orbiter and ESA’s Mercury Planetary Orbiter, will be carried together by the Mercury Transport Module. The carrier will use a combination of electric propulsion and multiple gravity-assists at Earth, Venus and Mercury to complete the 7.2 year journey to the Solar System’s mys-terious innermost planet.

Once at Mercury, the orbiters will separate and move into their own orbits to make complementary measurements of Mercury’s interior, surface, exosphere and magnetosphere. The information will tell us more about the origin and evo-lution of a planet close to its parent star, providing a better understanding of the overall evolution of our own Solar System.

To prepare for the harsh conditions close to the Sun, the spacecraft have undergone extensive testing both as sep-arate units, and in the 6 m-high launch and cruise config-uration.

One set of tests carried out earlier this year at ESA’s tech-nical centre in the Netherlands focused on deploying the solar wings, and the mechanisms that lock each panel in place. The 7.5 m-long array of the Mercury Planetary Or-biter and the two 12 m-long array of the Mercury Trans-port Module will be folded while inside the Ariane 5 rocket.Last month, the full spacecraft stack was tested inside the acoustic chamber, where the walls are fitted with power-ful speakers that reproduce the noise of launch.

Just last week, tests mimicked the intense vibrations ex-perienced by a satellite during launch. The complete stack was shaken at a range of frequencies, both in up-down and side-to-side motions. ...Read More...

Gaia Finds Six Stars Zipping out of the Milky Way

An artist’s conception of a hypervelocity star that has escaped the Milky Way. Image Credit: NASA

In 2013, the European Space Agency launched the Gaia spacecraft. As the successor to the Hipparcos mission, this space observatory has spent the past three and a half years gathering data on the cosmos. Before it retires sometime next year (though the mission could be extend-ed), this information will be used to construct the largest and most precise 3D astronomical map ever created.

In the course of surveying the cosmos, Gaia has also re-vealed some very interesting things along the way. For example, after examining the Gaia catalog with a special-ly-designed artificial neural network, a team of European researchers recently detected six new hypervelocity stars in the Milky Way. And one of these stars is moving so fast that it may eventually leave our galaxy.

Their study – titled “An Artificial Neural Network to Dis-cover Hypervelocity Stars: Candidates in Gaia DR1/TGAS” – was recently published in the Monthly Notices of the Royal Astronomical Society. It was presented late last month at the European Week of Astronomy and Space Sci-ence, which was being held from June 26th to June 30th in Prague, Czech Republic.

Hypervelocity stars are a rare and fascinating thing. Whereas all stars in the Milky Way are in constant mo-tion, orbiting around the center of our galaxy, some are accelerated to speeds of up to hundreds of kilometers per second. In the past, astronomers have deduced that these fast-moving stars are the result of a close stellar encoun-ter or a supernova explosion of a stellar companion.

And a little over a decade ago, astronomers became aware of a new class of high-speed stars that are believed to have been accelerated from past interactions with the supermassive black hole (Sagittarius A*) that sits at the center of our galaxy. These stars are extremely important to the study of the overall structure of the Milky Way, as they are indicative of the kinds of events and forces that have shaped its history.

As Elena Maria Rossi, from Leiden University in the Neth-erlands and one of the co-authors on the ...Read More...

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Physicists read Maxwell’s De-mon’s mind

Credit: CC0 Public Domain

Pioneering research offers a fascinating view into the in-ner workings of the mind of ‘Maxwell’s Demon’, a famous thought experiment in physics.

An international research team, including Dr Janet Anders from the University of Exeter, have used superconducting circuits to bring the ‘demon’ to life.

The demon, first proposed by James Clerk Maxwell in 1867, is a hypothetical being that can gain more useful energy from a thermodynamic system than one of the most fun-damental laws of physics—the second law of thermody-namics—should allow.

Crucially, the team not only directly observed the gained energy for the first time, they also tracked how informa-tion gets stored in the demon’s memory.

The research is published in the leading scientific journal Proceedings of the National Academy of Sciences (PNAS).

The original thought experiment was first proposed by mathematical physicist James Clerk Maxwell—one of the most influential scientists in history—150 years ago.

He hypothesised that gas particles in two adjacent boxes could be filtered by a ‘demon’ operating a tiny door, that allowed only fast energy particles to pass in one direction and low energy particles the opposite way.

As a result, one box gains a higher average energy than the other, which creates a pressure difference. This non-equi-librium situation can be used to gain energy, not unlike the energy obtained when water stored behind a dam is re-leased.

So although the gas was initially in equilibrium, the demon can create a non-equilibrium situation and extract energy, bypassing the second law of thermodynamics.

Dr Anders, a leading theoretical physicist from the Univer-sity of Exeter’s physics department adds: “In the 1980s it was discovered that this is not the full story. The informa-tion about the particles’ properties remains ..Read More...

Physicists provide support for retrocausal quantum the-ory, in which the future influ-ences the past

Can Bell correlations be explained by retrocausal influences? Fig-ure shows an influence diagram representing the possible causal influences in a model with no retrocausality. Credit: Leifer and Pusey. ©2017 The Royal Society

Although there are many counterintuitive ideas in quan-tum theory, the idea that influences can travel backwards in time (from the future to the past) is generally not one of them. However, recently some physicists have been look-ing into this idea, called “retrocausality,” because it can po-tentially resolve some long-standing puzzles in quantum physics. In particular, if retrocausality is allowed, then the famous Bell tests can be interpreted as evidence for ret-rocausality and not for action-at-a-distance—a result that Einstein and others skeptical of that “spooky” property may have appreciated.

In a new paper published in Proceedings of The Royal So-ciety A, physicists Matthew S. Leifer at Chapman Univer-sity and Matthew F. Pusey at the Perimeter Institute for Theoretical Physics have lent new theoretical support for the argument that, if certain reasonable-sounding assump-tions are made, then quantum theory must be retrocausal.

The appeal of retrocausality

First, to clarify what retrocausality is and isn’t: It does not mean that signals can be communicated from the future to the past—such signaling would be forbidden even in a retrocausal theory due to thermodynamic reasons. Instead, retrocausality means that, when an experimenter chooses the measurement setting with which to measure a particle, that decision can influence the properties of that particle (or another particle) in the past, even before the experi-menter made their choice. In other words, a decision made in the present can influence something in the past.

In the original Bell tests, physicists assumed that retro-causal influences could not happen. Consequently, in order to explain their observations that distant particles seem to immediately know what measurement is being made on the other, the only viable explanation was action-at-a-dis-tance. That is, the particles are somehow influencing each other even when separated by large distances, in ways that cannot be explained by any known mechanism. But by allowing for the possibility that the ..Read More...

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Scientists get first direct look at how electrons ‘dance’ with vibrating atoms

An animation shows how an infrared laser beam (orange) trig-gers atomic vibrations in a thin layer of iron selenide, which are then recorded by ultrafast X-ray laser pulses to create an ultra-fast movie. The motion of the selenium atoms (red) changes the energy of the electron orbitals of the iron atoms (blue), and the resulting electron vibrations are recorded separately with a tech-nique called ARPES (not shown). Credit: Greg Stewart/SLAC Na-tional Accelerator Laboratory

Scientists at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have made the first direct measurements, and by far the most precise ones, of how electrons move in sync with atomic vibrations rippling through an exotic material, as if they were dancing to the same beat.

The vibrations are called phonons, and the electron-phonon coupling the researchers measured was 10 times stronger than theory had predicted—making it strong enough to po-tentially play a role in unconventional superconductivity, which allows materials to conduct electricity with no loss at unexpectedly high temperatures.

What’s more, the approach they developed gives scientists a completely new and direct way to study a wide range of “emergent” materials whose surprising properties emerge from the collective behavior of fundamental particles, such as electrons. The new approach investigates these mate-rials through experiments alone, rather than relying on as-sumptions based on theory.

The experiments were carried out with SLAC’s Linac Coher-ent Light Source (LCLS) X-ray free-electron laser and with a technique called angle-resolved photoemission spectros-copy (ARPES) on the Stanford campus. The researchers de-scribed the study today in Science.

A ‘Breakthrough’ Approach

“I believe this result will have several impacts,” said Giulia Galli, a professor at the University of Chicago’s Institute for Molecular Engineering and senior scientist at the DOE’s Argonne National Laboratory who was not involved in the study.

“Of course they have applied the method to a very import-ant material, one that everyone has been trying to figure out and understand, and this is great,” ...Read More...

Mars surface ‘more uninhab-itable’ than thought: study

Latest lab tests show salt minerals on Mars kill basic life form bacteria, implying the ‘Red Planet’ is more uninhabitable than previously thought

Hopes of finding life on Mars, at least on the surface, were dealt a blow Thursday by a study revealing that salt minerals present on the Red Planet kill bacteria.

In lab tests on Earth, the compounds known as perchlo-rates killed cultures of the bacteria Bacillus subtilis, a ba-sic life form, a research duo from the University of Edin-burgh’s School of Physics and Astronomy reported.

Perchlorates, stable at room temperature, become active at high heat. Mars is very cold.

In the new study, Jennifer Wadsworth and Charles Coc-kell showed the compound can also be activated by UV light, without heat, in conditions mimicking those on the martian surface.

It killed bacteria within minutes, said the team, imply-ing the planet was “more uninhabitable than previously thought.”

“If we want to find life on Mars, we have to take this into consideration and look at trying to find sub-surface life that wouldn’t be exposed to these conditions,” Wad-sworth told AFP.

Perchlorates are natural and man-made on Earth, but are more abundant on Mars where they were first recorded by NASA’s Phoenix Lander in 2008.

The fact that perchlorates killed B. subtilis in the pres-ence of UV radiation did not necessarily mean that all other life forms would similarly die, said Wadsworth. Fur-ther tests would have to be done to confirm this.

Perchlorates have previously been spotted in lines, thought to be brine streaks, on the surface of Mars.

Their presence was presented as evidence by scientists in 2015 of liquid water on the Red Planet. But the new study said brine seeps, “although they represent local re-gions of water availability, could be deleterious to cells” if they contain perchlorates. ...Read More...

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Special Read:

NASA’S First Asteroid Deflection Mission Enters Next De-sign Phase

Artist concept of NASA’s Double Asteroid Redirection Test (DART) spacecraft. DART, which is moving to preliminary design phase, would be NASA’s first mission to demonstrate an asteroid deflection technique for planetary defense. Credits: NASA/JHUAPL

The first-ever mission to demonstrate an asteroid deflection technique for planetary defense - the Double Asteroid Redirection Test (DART) - is moving from concept development to preliminary design phase, following NASA’s approval on June 23.

“DART would be NASA’s first mission to demonstrate what’s known as the kinetic impactor technique - striking the as-teroid to shift its orbit - to defend against a potential future asteroid impact,” said Lindley Johnson, planetary defense officer at NASA Headquarters in Washington. “This approval step advances the project toward an historic test with a non-threatening small asteroid.”

While current law directs the development of the DART mission, DART is not identified as a specific budget item in the Administration’s Fiscal Year 2018 budget.

The target for DART is an asteroid that will have a distant approach to Earth in October 2022, and then again in 2024. The asteroid is called Didymos - Greek for “twin” - because it’s an asteroid binary system that consists of two bodies: Didymos A, about one-half mile (780 meters) in size, and a smaller asteroid orbiting it called Didymos B, about 530 feet (160 meters) in size. DART would impact only the smaller of the two bodies, Didymos B.

The Didymos system has been closely studied since 2003. The primary body is a rocky S-type object, with composition similar to that of many asteroids. The composition of its small companion, Didymos B, is unknown, but the size is typical of asteroids that could potentially create regional effects should they impact Earth.

“A binary asteroid is the perfect natural laboratory for this test,” said Tom Statler, program scientist for DART at NASA Headquarters. “The fact that Didymos B is in orbit around Didymos A makes it easier to see the results of the impact, and ensures that the experiment doesn’t change the orbit of the pair around the sun.”

After launch, DART would fly to Didymos, and use an on-board autonomous targeting system to aim itself at Didymos B. Then the refrigerator-sized spacecraft would strike the smaller body at a speed about nine times faster than a bullet, approximately 3.7 miles per second (6 kilometers per second). Earth-based observatories would be able to see the im-pact and the resulting change in the orbit of Didymos B around Didymos A, allowing scientists to better determine the capabilities of kinetic impact as an asteroid mitigation strategy.

The kinetic impact technique works by changing the speed of a threatening asteroid by a small fraction of its total velocity, but by doing it well before the predicted impact so that this small nudge will add up over time to a big shift of the asteroid’s path away from Earth. ...Read More...

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SCASS Summer Camp - July 09-12, 2017

This Week’s Sky at a Glance:July 08-14, 2017

Jul 09 Full Moon 08:06 Jul 12 Moon at descending node (09:17) Jul 13 Venus 3.1º N of Aldebaran (04:30)