Observer’s delight: Moon and Venus at dawn

A delicately beautiful sky scene awaits you on the mornings of May 30 and 31, plus June 1, 2019. On those mornings, you can use the waning crescent moon to find the planet Venus, now buried deep in eastern twilight before sunrise, especially as viewed from latitudes in the Northern Hemisphere. Although the moon and Venus rank as the 2nd-brightest and 3rd-brightest celestial bodies, respectively, after the sun, it’ll take a deliberate effort to spot them. You’ll need crystal-clear skies and an unobstructed horizon in the sunrise direction. Given favorable seeing conditions, you might witness the lovely close pairing of the moon and Venus on June 1. If the moon and Venus aren’t visible to the eye alone, try your luck with binoculars.

Why is this scene so wonderful to see? There’s something heart-stirring about seeing bright objects exceedingly low in the sky. We promise you … if you look, and you spot them, you’ll be glad.

The Southern Hemisphere has the big advantage over the Northern Hemisphere for watching this early morning drama. Within the Northern Hemisphere, the more southerly latitudes enjoy the advantage over more northerly latitudes. In fact, at far-northern latitudes – like Alaska – the moon and Venus will not visible at all; they rise after sunrise that far north on the globe. But at mid-northern latitudes and farther south, you have a reasonably good chance of spotting the waning crescent moon and Venus at dawn, from across the globe.

Brett Joseph captured the moon and planet Venus in the morning sky from San Anselmo, California on November 6, 2018.

From around the world, the moon will be the easiest to spot on May 30, because it’ll be a wider and brighter waning crescent, rising sooner before the sun (and Venus) on May 30 than on May 31 and June 1. The lit side of the lunar crescent will be pointing at Venus, so the moon acts as your arrow in the sky for locating Venus’ place near the horizon on May 30 and 31. The trick is to have patience, to wait for Venus to rise. It helps to know when Venus will rise into your sky. Here are the approximate rising times (presuming an unobstructed horizon) for various latitudes:

35 degrees north latitude: Venus rises one hour before the sun
Equator (0 degrees latitude): Venus rises 1 1/3 hours before the sun
35 degrees south latitude: Venus rises 1 2/3 hours before the sun

Click here for a recommended almanac that’ll more specifically give you Venus’ rising time into your sky.

Wherever you may be worldwide, use the lit side of the old moon to find Venus’ place near the horizon on May 30 and 31. Then try to remember where on the horizon you saw Venus on these two mornings. On June 1, a thinner and paler waning moon will be sitting lower in the sky and closer to Venus. From mid-northern latitudes, you might need to use binoculars to catch these two luminaries before sunrise June 1.

Bottom line: Good luck on catching the early morning spectacle on May 30, 31 and June 1, 2019. Two beautiful heavenly bodies – the moon and Venus – will be near the sunrise point, basking in the sweet glow of dawn.

from EarthSky http://bit.ly/2wpvGp5

A delicately beautiful sky scene awaits you on the mornings of May 30 and 31, plus June 1, 2019. On those mornings, you can use the waning crescent moon to find the planet Venus, now buried deep in eastern twilight before sunrise, especially as viewed from latitudes in the Northern Hemisphere. Although the moon and Venus rank as the 2nd-brightest and 3rd-brightest celestial bodies, respectively, after the sun, it’ll take a deliberate effort to spot them. You’ll need crystal-clear skies and an unobstructed horizon in the sunrise direction. Given favorable seeing conditions, you might witness the lovely close pairing of the moon and Venus on June 1. If the moon and Venus aren’t visible to the eye alone, try your luck with binoculars.

Why is this scene so wonderful to see? There’s something heart-stirring about seeing bright objects exceedingly low in the sky. We promise you … if you look, and you spot them, you’ll be glad.

The Southern Hemisphere has the big advantage over the Northern Hemisphere for watching this early morning drama. Within the Northern Hemisphere, the more southerly latitudes enjoy the advantage over more northerly latitudes. In fact, at far-northern latitudes – like Alaska – the moon and Venus will not visible at all; they rise after sunrise that far north on the globe. But at mid-northern latitudes and farther south, you have a reasonably good chance of spotting the waning crescent moon and Venus at dawn, from across the globe.

Brett Joseph captured the moon and planet Venus in the morning sky from San Anselmo, California on November 6, 2018.

From around the world, the moon will be the easiest to spot on May 30, because it’ll be a wider and brighter waning crescent, rising sooner before the sun (and Venus) on May 30 than on May 31 and June 1. The lit side of the lunar crescent will be pointing at Venus, so the moon acts as your arrow in the sky for locating Venus’ place near the horizon on May 30 and 31. The trick is to have patience, to wait for Venus to rise. It helps to know when Venus will rise into your sky. Here are the approximate rising times (presuming an unobstructed horizon) for various latitudes:

35 degrees north latitude: Venus rises one hour before the sun
Equator (0 degrees latitude): Venus rises 1 1/3 hours before the sun
35 degrees south latitude: Venus rises 1 2/3 hours before the sun

Click here for a recommended almanac that’ll more specifically give you Venus’ rising time into your sky.

Wherever you may be worldwide, use the lit side of the old moon to find Venus’ place near the horizon on May 30 and 31. Then try to remember where on the horizon you saw Venus on these two mornings. On June 1, a thinner and paler waning moon will be sitting lower in the sky and closer to Venus. From mid-northern latitudes, you might need to use binoculars to catch these two luminaries before sunrise June 1.

Bottom line: Good luck on catching the early morning spectacle on May 30, 31 and June 1, 2019. Two beautiful heavenly bodies – the moon and Venus – will be near the sunrise point, basking in the sweet glow of dawn.

from EarthSky http://bit.ly/2wpvGp5

Learning about advanced cancer from the people who donate their bodies after death

“Cancer has a way of evolving and adapting,” says Dr Mariam Jamal-Hanjani, a cancer doctor and researcher at the Cancer Research UK Lung Cancer Centre of Excellence. “When tumours are under selection pressures, for example as a result of cancer treatment, they can develop new features that allow them to become resistant and, therefore, more aggressive.”

Advanced cancers have often spread to other parts of the body. And it’s these secondary tumours that reach and compromise vital organs like the brain or lungs that can ultimately lead to death.

To tackle aggressive cancers, scientists need to understand how they evolve, spread and become resistant to treatment. But as cancer progresses and patients become more unwell, it becomes increasingly difficult to study.

Doctors might ask a patient for permission to use tissue removed during surgery for research. But when cancer has spread to multiple locations, or to somewhere that might not be possible to operate on or obtain a biopsy from, it isn’t possible to collect these gifts of precious tissue.

But now, thanks to an even greater gift to research, patients with advanced cancers are leaving a different type of legacy.

In new research, 10 patients with advanced breast cancer chose to donate their bodies after their death. Their gift allowed Cancer Research UK scientists in Cambridge to collect multiple samples of advanced cancer in all the places it had spread to – up to 37 tumours in a single patient. They analysed these samples to unravel how the cancers spread and developed treatment resistance, publishing their in-depth picture in the journal Cell Reports.

“It’s really an unprecedented view of lethal cancers,” says study lead Professor Carlos Caldas, from the Cancer Research UK Cambridge Institute.

Talking about death

Studies like this, and a larger national study called PEACE, involve collecting samples from patients after death and can sometimes require delicate conversations. For some patients the subject of death is a difficult one for many reasons, and patients are aware of the fact that their participation in studies like PEACE will not benefit themselves.

Despite how sensitive the topic is, patients often want to contribute to the research supported by PEACE, which is funded by Cancer Research UK. And they remain its biggest advocates.

“The truth is, even before PEACE existed I would often have patients ask me: ‘Is there anything I can do for science? Can I donate my body to research?’” recalls Jamal-Hanjani, who is the Principal Investigator for PEACE at the lead centre, UCL Cancer Institute.

“Our patients still want to give something of themselves to help cancer research, knowing that they won’t benefit, but that future patients might. It’s incredibly humbling.”

In these circumstances, a strong doctor-patient relationship is key to an open and honest conversation. Understanding how the patient feels is the main steer for doctors in whether to discuss participating in PEACE.

Although it can be intimidating, Jamal-Hanjani believes this is something doctors need to become more comfortable with. “In treating patients with cancer especially, we as doctors have to overcome that stigma, because patients do think about death and we need to allow them to speak freely with us.”

And these patients’ contribution can be invaluable in helping those who come after them.

Decoding cancer spread

Cancer evolution has become one of the big topics in research. Studies are analysing tumours from when they are first discovered and throughout treatment.

Now, samples collected after death are helping to understand the hardest to treat stages of some cancers. Caldas and his team compared multiple tumours collected from patients who had died from breast cancer that had become resistant to treatment.

The results paint a more comprehensive picture of how closely related tumours can be, retracing the steps that led to these cancers growing and spreading. Caldas says the results are unexpected.

“Our work suggests something rather extraordinary: that cancer spread is not a continuous process. It seems to happen in waves,” he says. Rather than new tumours appearing one after the other, each wave involves a group of cancer cells creating new tumours in several organs at the same time.

These could be cells breaking away from the primary tumour, or from elsewhere in the body where cancer cells can remain hidden and dormant for sometimes years.

“Even in patients who have a lot of secondary tumours,” adds Caldas, “cancer appears to have spread in as few as two or three of these waves.”

What triggers these waves? Could there be ‘pauses’ between them when cancer is unlikely to spread? Answers to these questions could change the way patients are monitored.

“This is just starting to open the book,” Caldas says. “There is a lot more to be learned from studies like this.”

The PEACE study is on a much larger scale: 150 patients have already volunteered in the first 2 years of the study. The research will focus on themes that scientists struggle to study without access to advanced cancer samples, like why certain cancers readily spread to specific organs but not others.

Coming together

Narrowing down the research questions to ensure these precious samples are used for the best possible research is an important aspect of PEACE.

A project of this scale also involves an element of unpredictability that represents a huge challenge for Jamal-Hanjani. Often, it’s a patient’s family who notifies the PEACE team that their loved one has died. An entire team must then come together very quickly, including researchers, laboratory staff, pathologists, mortuary technicians and clinical nurses.

“I would say that is far more challenging than talking to patients about death and about the PEACE study,” Jamal-Hanjani says.

Yet she feels a sense of responsibility. “Ultimately, we make a promise to the patient when they are alive, and we want to fulfil the living wish of our patients,” she says.

“We want our patients to know that even after they die, we will treat them with dignity and respect. We are very privileged to receive their samples and to be able to do the research we do.”

Paying it forward

As we start to better understand the behaviour of advanced cancers, PEACE and other post-mortem studies continue to centre on the people affected. For those who take part, this is their legacy.

“The vast majority of patients want to help other patients,” says Jamal-Hanjani. “I think that’s just the nature of human beings.”

That legacy will support many ongoing research projects focusing on several types of cancers, including lung, kidney, skin and breast, to name a few. Not only that, but samples will also be stored so that PEACE can contribute to future research projects. “It’s about the research we can do now, but also the research we can offer future doctors and scientists,” says Jamal-Hanjani.

Daimona Kounde is a science media officer at Cancer Research UK

Reference

De Mattos-Arruda, L, et al. (2019) The Genomic and Immune Landscapes of Lethal Metastatic Breast Cancer. Cell Reports. DOI:10.1016/j.celrep.2019.04.098

from Cancer Research UK – Science blog http://bit.ly/2QvYYLU

“Cancer has a way of evolving and adapting,” says Dr Mariam Jamal-Hanjani, a cancer doctor and researcher at the Cancer Research UK Lung Cancer Centre of Excellence. “When tumours are under selection pressures, for example as a result of cancer treatment, they can develop new features that allow them to become resistant and, therefore, more aggressive.”

Advanced cancers have often spread to other parts of the body. And it’s these secondary tumours that reach and compromise vital organs like the brain or lungs that can ultimately lead to death.

To tackle aggressive cancers, scientists need to understand how they evolve, spread and become resistant to treatment. But as cancer progresses and patients become more unwell, it becomes increasingly difficult to study.

Doctors might ask a patient for permission to use tissue removed during surgery for research. But when cancer has spread to multiple locations, or to somewhere that might not be possible to operate on or obtain a biopsy from, it isn’t possible to collect these gifts of precious tissue.

But now, thanks to an even greater gift to research, patients with advanced cancers are leaving a different type of legacy.

In new research, 10 patients with advanced breast cancer chose to donate their bodies after their death. Their gift allowed Cancer Research UK scientists in Cambridge to collect multiple samples of advanced cancer in all the places it had spread to – up to 37 tumours in a single patient. They analysed these samples to unravel how the cancers spread and developed treatment resistance, publishing their in-depth picture in the journal Cell Reports.

“It’s really an unprecedented view of lethal cancers,” says study lead Professor Carlos Caldas, from the Cancer Research UK Cambridge Institute.

Talking about death

Studies like this, and a larger national study called PEACE, involve collecting samples from patients after death and can sometimes require delicate conversations. For some patients the subject of death is a difficult one for many reasons, and patients are aware of the fact that their participation in studies like PEACE will not benefit themselves.

Despite how sensitive the topic is, patients often want to contribute to the research supported by PEACE, which is funded by Cancer Research UK. And they remain its biggest advocates.

“The truth is, even before PEACE existed I would often have patients ask me: ‘Is there anything I can do for science? Can I donate my body to research?’” recalls Jamal-Hanjani, who is the Principal Investigator for PEACE at the lead centre, UCL Cancer Institute.

“Our patients still want to give something of themselves to help cancer research, knowing that they won’t benefit, but that future patients might. It’s incredibly humbling.”

In these circumstances, a strong doctor-patient relationship is key to an open and honest conversation. Understanding how the patient feels is the main steer for doctors in whether to discuss participating in PEACE.

Although it can be intimidating, Jamal-Hanjani believes this is something doctors need to become more comfortable with. “In treating patients with cancer especially, we as doctors have to overcome that stigma, because patients do think about death and we need to allow them to speak freely with us.”

And these patients’ contribution can be invaluable in helping those who come after them.

Decoding cancer spread

Cancer evolution has become one of the big topics in research. Studies are analysing tumours from when they are first discovered and throughout treatment.

Now, samples collected after death are helping to understand the hardest to treat stages of some cancers. Caldas and his team compared multiple tumours collected from patients who had died from breast cancer that had become resistant to treatment.

The results paint a more comprehensive picture of how closely related tumours can be, retracing the steps that led to these cancers growing and spreading. Caldas says the results are unexpected.

“Our work suggests something rather extraordinary: that cancer spread is not a continuous process. It seems to happen in waves,” he says. Rather than new tumours appearing one after the other, each wave involves a group of cancer cells creating new tumours in several organs at the same time.

These could be cells breaking away from the primary tumour, or from elsewhere in the body where cancer cells can remain hidden and dormant for sometimes years.

“Even in patients who have a lot of secondary tumours,” adds Caldas, “cancer appears to have spread in as few as two or three of these waves.”

What triggers these waves? Could there be ‘pauses’ between them when cancer is unlikely to spread? Answers to these questions could change the way patients are monitored.

“This is just starting to open the book,” Caldas says. “There is a lot more to be learned from studies like this.”

The PEACE study is on a much larger scale: 150 patients have already volunteered in the first 2 years of the study. The research will focus on themes that scientists struggle to study without access to advanced cancer samples, like why certain cancers readily spread to specific organs but not others.

Coming together

Narrowing down the research questions to ensure these precious samples are used for the best possible research is an important aspect of PEACE.

A project of this scale also involves an element of unpredictability that represents a huge challenge for Jamal-Hanjani. Often, it’s a patient’s family who notifies the PEACE team that their loved one has died. An entire team must then come together very quickly, including researchers, laboratory staff, pathologists, mortuary technicians and clinical nurses.

“I would say that is far more challenging than talking to patients about death and about the PEACE study,” Jamal-Hanjani says.

Yet she feels a sense of responsibility. “Ultimately, we make a promise to the patient when they are alive, and we want to fulfil the living wish of our patients,” she says.

“We want our patients to know that even after they die, we will treat them with dignity and respect. We are very privileged to receive their samples and to be able to do the research we do.”

Paying it forward

As we start to better understand the behaviour of advanced cancers, PEACE and other post-mortem studies continue to centre on the people affected. For those who take part, this is their legacy.

“The vast majority of patients want to help other patients,” says Jamal-Hanjani. “I think that’s just the nature of human beings.”

That legacy will support many ongoing research projects focusing on several types of cancers, including lung, kidney, skin and breast, to name a few. Not only that, but samples will also be stored so that PEACE can contribute to future research projects. “It’s about the research we can do now, but also the research we can offer future doctors and scientists,” says Jamal-Hanjani.

Daimona Kounde is a science media officer at Cancer Research UK

Reference

De Mattos-Arruda, L, et al. (2019) The Genomic and Immune Landscapes of Lethal Metastatic Breast Cancer. Cell Reports. DOI:10.1016/j.celrep.2019.04.098

from Cancer Research UK – Science blog http://bit.ly/2QvYYLU

Ancient ice sheets found under Mars’ north pole

A view of Mars showing the planet’s northern polar ice cap. Image via ISRO/ISSDC/Emily Lakdawalla.

Scientists have discovered remnants of ancient ice sheets buried in sand a mile (1.6 km) beneath Mars’ north pole, they report in a new study.

The team found layers of sand and ice that were as much as 90 percent water in some places. If it melted, the newly-discovered ice would be equivalent to a global layer of water around Mars at least 5 feet (1.5 meters) deep, which could be one of the largest water reservoirs on the planet, according to the researchers.

A vertically exaggerated view of Mars’ north polar cap. Image via SA/DLR/FU Berlin; NASA MGS MOLA Science Team.

Stefano Nerozzi is a graduate research assistant at the University of Texas Institute for Geophysics and lead author of the new study, published May 22, 2019, in the peer-reviewed journal Geophysical Research Letters, He said in a statement:

We didn’t expect to find this much water ice here. That likely makes it the third largest water reservoir on Mars after the polar ice caps.

The researchers made the discovery using measurements gathered by an instrument on NASA’s Mars Reconnaissance Orbiter, called SHARAD, that emits radar waves that can penetrate up to a mile and a half (2.4 km) beneath Mars’s surface.

The layers of ice are a record of past climate on Mars in much the same way that tree rings are a record of past climate on Earth, according to the researchers. They suspect the layers formed when ice accumulated at the poles during past ice ages on Mars. Each time the planet warmed, a remnant of the ice caps became covered by sand, which protected the ice from solar radiation and prevented it from dissipating into the atmosphere.

Here’s more from a statement from the researchers:

Scientists have long known about glacial events on Mars, which are driven by variations in the planet’s orbit and tilt. Over periods of about 50,000 years, Mars leans toward the sun before gradually returning to an upright position, like a wobbling spinning top. When the planet spins upright, the equator faces the sun, allowing the polar ice caps to grow. As the planet tilts, the ice caps retreat, perhaps vanishing entirely.

Until now, scientists thought the ancient ice caps were lost. The new findings show that in fact significant ice sheet remnants have survived under the planet’s surface, trapped in alternating bands of ice and sand, like layers on a cake.

The photograph, taken with the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter, was adjusted to show water ice as light-colored layers and sand as darker layers of blue. The tiny bright white flecks are thin patches of frost. Image via NASA/JPL/University of Arizona.

Jack Holt is a professor at the Lunar and Planetary Laboratory of the University of Arizona and co-author of the new study. He said:

Surprisingly, the total volume of water locked up in these buried polar deposits is roughly the same as all the water ice known to exist in glaciers and buried ice layers at lower latitudes on Mars, and they are approximately the same age.

Studying this record of past polar glaciation could help determine whether Mars was ever habitable, according to Nerozzi.

Understanding how much water was available globally versus what’s trapped in the poles is important if you’re going to have liquid water on Mars.You can have all the right conditions for life, but if most of the water is locked up at the poles, then it becomes difficult to have sufficient amounts of liquid water near the equator.

The findings were corroborated by an independent study using gravity data instead of radar, also published today in Geophysical Research Letters.

Bottom line: Scientists have discovered remnants of ancient ice sheets on Mars buried in sand a mile (1.6 km) beneath Mars’ north pole, which, if melted, could cover the entire planet 5 feet (1.5 m) deep in water.

Source: Buried ice and sand caps at the north pole of Mars: revealing a record of climate change in the cavi unit with SHARAD

Via AGU

from EarthSky http://bit.ly/2XbpRaw

A view of Mars showing the planet’s northern polar ice cap. Image via ISRO/ISSDC/Emily Lakdawalla.

Scientists have discovered remnants of ancient ice sheets buried in sand a mile (1.6 km) beneath Mars’ north pole, they report in a new study.

The team found layers of sand and ice that were as much as 90 percent water in some places. If it melted, the newly-discovered ice would be equivalent to a global layer of water around Mars at least 5 feet (1.5 meters) deep, which could be one of the largest water reservoirs on the planet, according to the researchers.

A vertically exaggerated view of Mars’ north polar cap. Image via SA/DLR/FU Berlin; NASA MGS MOLA Science Team.

Stefano Nerozzi is a graduate research assistant at the University of Texas Institute for Geophysics and lead author of the new study, published May 22, 2019, in the peer-reviewed journal Geophysical Research Letters, He said in a statement:

We didn’t expect to find this much water ice here. That likely makes it the third largest water reservoir on Mars after the polar ice caps.

The researchers made the discovery using measurements gathered by an instrument on NASA’s Mars Reconnaissance Orbiter, called SHARAD, that emits radar waves that can penetrate up to a mile and a half (2.4 km) beneath Mars’s surface.

The layers of ice are a record of past climate on Mars in much the same way that tree rings are a record of past climate on Earth, according to the researchers. They suspect the layers formed when ice accumulated at the poles during past ice ages on Mars. Each time the planet warmed, a remnant of the ice caps became covered by sand, which protected the ice from solar radiation and prevented it from dissipating into the atmosphere.

Here’s more from a statement from the researchers:

Scientists have long known about glacial events on Mars, which are driven by variations in the planet’s orbit and tilt. Over periods of about 50,000 years, Mars leans toward the sun before gradually returning to an upright position, like a wobbling spinning top. When the planet spins upright, the equator faces the sun, allowing the polar ice caps to grow. As the planet tilts, the ice caps retreat, perhaps vanishing entirely.

Until now, scientists thought the ancient ice caps were lost. The new findings show that in fact significant ice sheet remnants have survived under the planet’s surface, trapped in alternating bands of ice and sand, like layers on a cake.

The photograph, taken with the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter, was adjusted to show water ice as light-colored layers and sand as darker layers of blue. The tiny bright white flecks are thin patches of frost. Image via NASA/JPL/University of Arizona.

Jack Holt is a professor at the Lunar and Planetary Laboratory of the University of Arizona and co-author of the new study. He said:

Surprisingly, the total volume of water locked up in these buried polar deposits is roughly the same as all the water ice known to exist in glaciers and buried ice layers at lower latitudes on Mars, and they are approximately the same age.

Studying this record of past polar glaciation could help determine whether Mars was ever habitable, according to Nerozzi.

Understanding how much water was available globally versus what’s trapped in the poles is important if you’re going to have liquid water on Mars.You can have all the right conditions for life, but if most of the water is locked up at the poles, then it becomes difficult to have sufficient amounts of liquid water near the equator.

The findings were corroborated by an independent study using gravity data instead of radar, also published today in Geophysical Research Letters.

Bottom line: Scientists have discovered remnants of ancient ice sheets on Mars buried in sand a mile (1.6 km) beneath Mars’ north pole, which, if melted, could cover the entire planet 5 feet (1.5 m) deep in water.

Source: Buried ice and sand caps at the north pole of Mars: revealing a record of climate change in the cavi unit with SHARAD

Via AGU

from EarthSky http://bit.ly/2XbpRaw

Giant planets and comets battle in planet-forming disk

Image from the ALMA telescope in Chile – not an artist’s concept – of the young star HD 163296. The star is surrounded by a disk of gas and dust, where at least 3 giant planets are thought to be forming … duking it out with this system’s future comets and asteroids. Image via ALMA/S. Dagnello/Istituto Nazionale di Astrofisica.

The Istituto Nazionale di Astrofisica (INAF) – headquartered in Rome, Italy – announced a new study on May 23, 2019, that provides a key glimpse into the process by which solar systems build their planets. The study is based on observations with the ALMA telescope in Chile. It explored whether the anomalous features in the dust and gas distributions in the planet-forming disk of a distant star – called HD 163296 – could arise from an interaction of the system’s giant planets with its planetesimals, or planet-building blocks. Leftover planetesimals, those that don’t go into forming planets, will one day become this system’s asteroids and comets.

The new study is published in the peer-reviewed Astrophysical Journal.

For centuries, astronomers have theorized that planets form in a flattened disk of gas and dust encircling a newly born star. In 2014, ALMA became the first to capture detailed images of these circumstellar disks, specifically a first image of bright concentric rings in a disk, around the star HL Tau. Thus the process by which solar systems are born is being revealed. Since then, ALMA has been capturing even smaller-scale structures in circumstellar disks – gaps, rings and spiral arms – most of them believed to be linked to the presence of young planets and to arise from the interplay of the new planets’ gravity with their surroundings. A statement from INAF explained:

Among the best-studied disks observed by ALMA is that surrounding HD 163296, a 5 million-year-old star about twice the mass of our sun. HD 163296’s disk is both massive (a bit less than one tenth of the sun’s mass) and wide (about 500 au, twice the outer boundary of the Kuiper Belt in the solar system) and has been proposed to be home to at least three planets with masses comprised between twice that of Uranus and the one of Jupiter. ALMA’s most recent observations allowed to spatially and compositionally characterize the structure of HD 163296’s disk to a level previously undreamed of and showed how dust is still quite abundant (more than 300 times the mass of the Earth) in this disk notwithstanding its age and having produced at least three giant planets. The same observations also revealed some strange behaviors of the dust spatial distribution that could not easily be explained only as the result of its interplay with the gas and the newly formed giant planets.

As planets form in a disk, the dust in the disk is thought to be swept up, so that it decreases over time. Astronomers expected dust to disappear over time from the region immediately inside HD 163296’s innermost planet. At the same time, they thought, dust coming from the outer regions of the disk should pile up outside the orbits of the second and third planets. ALMA’s observations revealed instead that the regions inside the first planet and between the first and second planets have some of the highest concentrations of dust of the whole disk. The new study explored whether these anomalous dust features could arise from the interaction of the giant planets with a component of the disk previously unaccounted for: the planetesimals.

Diego Turrini of INAF – lead author of the study – said:

From the study of the solar system we know that mature circumstellar disks like HD 163296 are not composed only by gas and dust, but also contain an invisible population of small planetary objects similar to our asteroids and comets.

Astronomer Diego Turrini of the Istituto Nazionale di Astrofisica, headquartered in Rome. He led a team that explored small-scale structures in the dusk in the disk around the star HD 163296. Image via INAF.

Turrini and his colleagues performed computer simulations showing how, during the growth of HD 163296’s three giant planets, a larger and larger fraction of the surrounding population of planetesimals is injected on very eccentric and very inclined orbits similar to those of the comets in our solar system. Francesco Marzari of the University of Padova, co-author of the study, commented:

The main outcome of this dynamical excitation is a higher rate of violent collisions among the planetesimals.

The team found that the collisions among planetesimals remain quite gentle until the giant planets approach their final masses but then they rapidly grow a hundredfold in violence and start grinding down the planetesimals. Marzari said:

These violent collisions replenish the dust population in the disk. The new dust produced by this process, however, has a different orbital distribution than the original one and mainly concentrates in two places: the orbital region within the first giant planet and the ring between the first and the second giant planets.

Read more details about the outcome of the study here

Leonardo Testi, also co-author of the study and head of the ALMA Support Center of the European Southern Observatory, said:

This study was started as a pathfinder project to explore whether the dynamical excitation caused by newly formed giant planets could actually produce observable effects. As such, we just scratched the surface of this process and its implications. Nevertheless, its physical recipe is quite simple: massive planets forming in a disk of planetesimals. Given the widespread signatures of possible young giant planets we are discovering with ALMA and the extended duration of the dynamical effects caused by their appearance, we might be looking to a process that is quite common among circumstellar disks.

And so the question of how our Earth and solar system were made is being answered!

Graphic showing the disk of icy planetesimals hidden in HD 163296’s circumstellar disk seen from above and the side. The young giant planets rapidly create a large population of exocomets acting as high-speed projectiles for the other bodies. Image via D. Turrini/INAF-IAPS.

Bottom line: New telescopic observations of young star HD 163296 show rings of dust in its surrounding dust cloud indicating that giant planets are interacting with small bodies that will become asteroids and comets.

Source: Dust-to-gas Ratio Resurgence in Circumstellar Disks Due to the Formation of Giant Planets: The Case of HD 163296

Read more via INAF

from EarthSky http://bit.ly/2QvVCbP

Image from the ALMA telescope in Chile – not an artist’s concept – of the young star HD 163296. The star is surrounded by a disk of gas and dust, where at least 3 giant planets are thought to be forming … duking it out with this system’s future comets and asteroids. Image via ALMA/S. Dagnello/Istituto Nazionale di Astrofisica.

The Istituto Nazionale di Astrofisica (INAF) – headquartered in Rome, Italy – announced a new study on May 23, 2019, that provides a key glimpse into the process by which solar systems build their planets. The study is based on observations with the ALMA telescope in Chile. It explored whether the anomalous features in the dust and gas distributions in the planet-forming disk of a distant star – called HD 163296 – could arise from an interaction of the system’s giant planets with its planetesimals, or planet-building blocks. Leftover planetesimals, those that don’t go into forming planets, will one day become this system’s asteroids and comets.

The new study is published in the peer-reviewed Astrophysical Journal.

For centuries, astronomers have theorized that planets form in a flattened disk of gas and dust encircling a newly born star. In 2014, ALMA became the first to capture detailed images of these circumstellar disks, specifically a first image of bright concentric rings in a disk, around the star HL Tau. Thus the process by which solar systems are born is being revealed. Since then, ALMA has been capturing even smaller-scale structures in circumstellar disks – gaps, rings and spiral arms – most of them believed to be linked to the presence of young planets and to arise from the interplay of the new planets’ gravity with their surroundings. A statement from INAF explained:

Among the best-studied disks observed by ALMA is that surrounding HD 163296, a 5 million-year-old star about twice the mass of our sun. HD 163296’s disk is both massive (a bit less than one tenth of the sun’s mass) and wide (about 500 au, twice the outer boundary of the Kuiper Belt in the solar system) and has been proposed to be home to at least three planets with masses comprised between twice that of Uranus and the one of Jupiter. ALMA’s most recent observations allowed to spatially and compositionally characterize the structure of HD 163296’s disk to a level previously undreamed of and showed how dust is still quite abundant (more than 300 times the mass of the Earth) in this disk notwithstanding its age and having produced at least three giant planets. The same observations also revealed some strange behaviors of the dust spatial distribution that could not easily be explained only as the result of its interplay with the gas and the newly formed giant planets.

As planets form in a disk, the dust in the disk is thought to be swept up, so that it decreases over time. Astronomers expected dust to disappear over time from the region immediately inside HD 163296’s innermost planet. At the same time, they thought, dust coming from the outer regions of the disk should pile up outside the orbits of the second and third planets. ALMA’s observations revealed instead that the regions inside the first planet and between the first and second planets have some of the highest concentrations of dust of the whole disk. The new study explored whether these anomalous dust features could arise from the interaction of the giant planets with a component of the disk previously unaccounted for: the planetesimals.

Diego Turrini of INAF – lead author of the study – said:

From the study of the solar system we know that mature circumstellar disks like HD 163296 are not composed only by gas and dust, but also contain an invisible population of small planetary objects similar to our asteroids and comets.

Astronomer Diego Turrini of the Istituto Nazionale di Astrofisica, headquartered in Rome. He led a team that explored small-scale structures in the dusk in the disk around the star HD 163296. Image via INAF.

Turrini and his colleagues performed computer simulations showing how, during the growth of HD 163296’s three giant planets, a larger and larger fraction of the surrounding population of planetesimals is injected on very eccentric and very inclined orbits similar to those of the comets in our solar system. Francesco Marzari of the University of Padova, co-author of the study, commented:

The main outcome of this dynamical excitation is a higher rate of violent collisions among the planetesimals.

The team found that the collisions among planetesimals remain quite gentle until the giant planets approach their final masses but then they rapidly grow a hundredfold in violence and start grinding down the planetesimals. Marzari said:

These violent collisions replenish the dust population in the disk. The new dust produced by this process, however, has a different orbital distribution than the original one and mainly concentrates in two places: the orbital region within the first giant planet and the ring between the first and the second giant planets.

Read more details about the outcome of the study here

Leonardo Testi, also co-author of the study and head of the ALMA Support Center of the European Southern Observatory, said:

This study was started as a pathfinder project to explore whether the dynamical excitation caused by newly formed giant planets could actually produce observable effects. As such, we just scratched the surface of this process and its implications. Nevertheless, its physical recipe is quite simple: massive planets forming in a disk of planetesimals. Given the widespread signatures of possible young giant planets we are discovering with ALMA and the extended duration of the dynamical effects caused by their appearance, we might be looking to a process that is quite common among circumstellar disks.

And so the question of how our Earth and solar system were made is being answered!

Graphic showing the disk of icy planetesimals hidden in HD 163296’s circumstellar disk seen from above and the side. The young giant planets rapidly create a large population of exocomets acting as high-speed projectiles for the other bodies. Image via D. Turrini/INAF-IAPS.

Bottom line: New telescopic observations of young star HD 163296 show rings of dust in its surrounding dust cloud indicating that giant planets are interacting with small bodies that will become asteroids and comets.

Source: Dust-to-gas Ratio Resurgence in Circumstellar Disks Due to the Formation of Giant Planets: The Case of HD 163296

Read more via INAF

from EarthSky http://bit.ly/2QvVCbP

Watch ISS spacewalk May 29

Russian spacewalkers Oleg Kononenko (suit with red stripes) and Sergey Prokopyev (suit with blue stripes) work outside the International Space Station, more than 250 miles (400 km) above Earth to inspect the Soyuz MS-09 spacecraft, on December 11, 2018. Image via NASA.

Two veteran Russian cosmonauts will venture outside the International Space Station (ISS) for a spacewalk on Wednesday, May 29, 2019. NASA TV’s live coverage begins at 15:15 UTC (11:15 a.m. EDT); translate UTC to your time. The spacewalk itself is scheduled to start at 15:44 UTC (11:44 a.m. EDT) and is expected to last 6.5 hours. Watch here.

The cosmonauts, Expedition 59 Commander Oleg Kononenko and Flight Engineer Alexey Ovchinin, will retrieve science experiments, install handrails on the Russian segment of the complex, and conduct maintenance on the orbiting laboratory.

This will be the fifth spacewalk for Kononenko, who will be designated extravehicular crew member 1 (EV1), in the suit with blue stripes, and the first for Ovchinin, who will be EV2, in the suit with red stripes. Wednesday’s spacewalk will be the 217th in support of station assembly, maintenance and upgrades and the fourth outside the station in 2019.

View larger. | There have been 216 spacewalks at the International Space Station since December 1998. See a list. Image via NASA.

Cosmonaut Oleg Kononenko, seen here during a 2012 spacewalk with Anton Shkaplerov, is getting ready for another spacewalk set for 11:44am ET Wednesday with first-time spacewalker Alexey Ovchinin. NASA TV begins its broadcast live at 11:15am. #AskNASA | https://t.co/ZjxuLPFfxg pic.twitter.com/Shyx1G4sfQ

— Intl. Space Station (@Space_Station) May 26, 2019

Bottom line: How to watch ISS Russian cosmonauts’ spacewalk on May 29, 2019.

Via NASA

from EarthSky http://bit.ly/2JJJiV8

Russian spacewalkers Oleg Kononenko (suit with red stripes) and Sergey Prokopyev (suit with blue stripes) work outside the International Space Station, more than 250 miles (400 km) above Earth to inspect the Soyuz MS-09 spacecraft, on December 11, 2018. Image via NASA.

Two veteran Russian cosmonauts will venture outside the International Space Station (ISS) for a spacewalk on Wednesday, May 29, 2019. NASA TV’s live coverage begins at 15:15 UTC (11:15 a.m. EDT); translate UTC to your time. The spacewalk itself is scheduled to start at 15:44 UTC (11:44 a.m. EDT) and is expected to last 6.5 hours. Watch here.

The cosmonauts, Expedition 59 Commander Oleg Kononenko and Flight Engineer Alexey Ovchinin, will retrieve science experiments, install handrails on the Russian segment of the complex, and conduct maintenance on the orbiting laboratory.

This will be the fifth spacewalk for Kononenko, who will be designated extravehicular crew member 1 (EV1), in the suit with blue stripes, and the first for Ovchinin, who will be EV2, in the suit with red stripes. Wednesday’s spacewalk will be the 217th in support of station assembly, maintenance and upgrades and the fourth outside the station in 2019.

View larger. | There have been 216 spacewalks at the International Space Station since December 1998. See a list. Image via NASA.

Cosmonaut Oleg Kononenko, seen here during a 2012 spacewalk with Anton Shkaplerov, is getting ready for another spacewalk set for 11:44am ET Wednesday with first-time spacewalker Alexey Ovchinin. NASA TV begins its broadcast live at 11:15am. #AskNASA | https://t.co/ZjxuLPFfxg pic.twitter.com/Shyx1G4sfQ

— Intl. Space Station (@Space_Station) May 26, 2019

Bottom line: How to watch ISS Russian cosmonauts’ spacewalk on May 29, 2019.

Via NASA

from EarthSky http://bit.ly/2JJJiV8

Which moon phase is best for stargazing?

Looking for the moon? It’s up in the early morning now, in a waning crescent phase. Astronomers call the moon at this phase an old moon. You’ll find it rising in the wee hours, drawing closer each morning this week to the bright planet Venus. We received this question:

Which phase of the moon would be best for stargazing, and why?

And the answer is … it depends on what you want to do. Some people enjoy watching the moon itself, as it waxes and wanes in our sky. Some enjoy the fact that the moon appears near bright stars and planets at certain times of the month. For instance, the lit side of tomorrow morning’s (May 30) waning crescent moon will point right at Venus, making it easier to locate and see this world at morning dawn.

Some professional astronomers don’t care about observing the moon itself. They are more interested in observing objects in space much farther away than Earth’s moon. They look forward to moon-free nights, which let them look at deep-sky objects, such as galaxies, star clusters and nebulae. They like the moon at or near new phase! It’s best to look at these faint fuzzies in a night sky with little or no light.

The moon is our companion world, and we love her. But astronomers trying to observe faint objects typically avoid the moon. Image via NASA.

Amateur astronomers using telescopes may also try to avoid the moon, because its glare interferes with the telescopic views of deep-sky objects. Especially around full moon, the moon casts a lot of light, washing out many nighttime treasures. At new moon, the moon is up during the day, not the nighttime. Around then, you won’t see the moon at all – unless you’re on just the right spot on Earth to watch one of the upcoming solar eclipses on July 2 and December 26, 2019.

In the meantime, what do we have to look forward to in the week or so ahead? Watch for the moon to swing closer to Venus in the late May morning sky, and then for the moon to swing over into the evening sky in early June, to join up with Mercury and Mars at evening dusk.

Moon phases: 1) new moon 2) waxing crescent 3) first quarter 4) waxing gibbous 5) full moon 6) waning gibbous 7) last quarter 8) waning crescent. For more, read Four keys to understanding moon phases.

Bottom line: The best phase of the moon for stargazing depends on what you want to do. Some enjoy watching the moon itself. On the other hand, people using telescopes avoid the moon because its glare interferes with deep-sky objects.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

from EarthSky http://bit.ly/30QvGfI

Looking for the moon? It’s up in the early morning now, in a waning crescent phase. Astronomers call the moon at this phase an old moon. You’ll find it rising in the wee hours, drawing closer each morning this week to the bright planet Venus. We received this question:

Which phase of the moon would be best for stargazing, and why?

And the answer is … it depends on what you want to do. Some people enjoy watching the moon itself, as it waxes and wanes in our sky. Some enjoy the fact that the moon appears near bright stars and planets at certain times of the month. For instance, the lit side of tomorrow morning’s (May 30) waning crescent moon will point right at Venus, making it easier to locate and see this world at morning dawn.

Some professional astronomers don’t care about observing the moon itself. They are more interested in observing objects in space much farther away than Earth’s moon. They look forward to moon-free nights, which let them look at deep-sky objects, such as galaxies, star clusters and nebulae. They like the moon at or near new phase! It’s best to look at these faint fuzzies in a night sky with little or no light.

The moon is our companion world, and we love her. But astronomers trying to observe faint objects typically avoid the moon. Image via NASA.

Amateur astronomers using telescopes may also try to avoid the moon, because its glare interferes with the telescopic views of deep-sky objects. Especially around full moon, the moon casts a lot of light, washing out many nighttime treasures. At new moon, the moon is up during the day, not the nighttime. Around then, you won’t see the moon at all – unless you’re on just the right spot on Earth to watch one of the upcoming solar eclipses on July 2 and December 26, 2019.

In the meantime, what do we have to look forward to in the week or so ahead? Watch for the moon to swing closer to Venus in the late May morning sky, and then for the moon to swing over into the evening sky in early June, to join up with Mercury and Mars at evening dusk.

Moon phases: 1) new moon 2) waxing crescent 3) first quarter 4) waxing gibbous 5) full moon 6) waning gibbous 7) last quarter 8) waning crescent. For more, read Four keys to understanding moon phases.

Bottom line: The best phase of the moon for stargazing depends on what you want to do. Some enjoy watching the moon itself. On the other hand, people using telescopes avoid the moon because its glare interferes with deep-sky objects.

A planisphere is virtually indispensable for beginning stargazers. Order your EarthSky planisphere today.

from EarthSky http://bit.ly/30QvGfI

What is a waning crescent moon?

Here’s a waning crescent moon – 27% illuminated, with earthshine – and showing a humidity-induced lens flare. Photo by Greg Diesel Walck – Lunar/Landscape Photographer.

In the week following last quarter moon, the moon continues to wane. You’ll see it as a waning crescent moon – sometimes called an old moon – visible in the east before dawn.

Each morning, the moon shows us less and less of its lighted side. It rises closer to the sunrise, heading for new moon.

Want to know a sky trick? The illuminated side of a waning crescent moon always points eastward, or in the direction of sunrise.

Moreover, the lit side of waning crescent points in the direction of the moon’s daily motion relative to the backdrop stars and planets of the zodiac. That direction is also east.

Many people miss the waning crescent moon because it’s a morning moon, visible before sunrise. But it’s fun to follow the waning crescent day by day, as it inches into the dawn glare.

As the moon orbits Earth, it changes phase in an orderly way. Follow the links below to understand the phases of the moon.

New moon
Waxing crescent moon
First quarter moon
Waxing gibbous moon
Full moon
Waning gibbous moon
Last quarter moon
Waning crescent moon

Read more: 4 keys to understanding moon phases

Waning crescent moon from Russ Adams in Pike County, Illinois. Thanks, Russ!

Bottom line: A waning crescent moon comes between last quarter moon and new moon.

Check out EarthSky’s guide to the bright planets.

Help EarthSky keep going! Please donate.

from EarthSky http://bit.ly/2WzeRac

Here’s a waning crescent moon – 27% illuminated, with earthshine – and showing a humidity-induced lens flare. Photo by Greg Diesel Walck – Lunar/Landscape Photographer.

In the week following last quarter moon, the moon continues to wane. You’ll see it as a waning crescent moon – sometimes called an old moon – visible in the east before dawn.

Each morning, the moon shows us less and less of its lighted side. It rises closer to the sunrise, heading for new moon.

Want to know a sky trick? The illuminated side of a waning crescent moon always points eastward, or in the direction of sunrise.

Moreover, the lit side of waning crescent points in the direction of the moon’s daily motion relative to the backdrop stars and planets of the zodiac. That direction is also east.

Many people miss the waning crescent moon because it’s a morning moon, visible before sunrise. But it’s fun to follow the waning crescent day by day, as it inches into the dawn glare.

As the moon orbits Earth, it changes phase in an orderly way. Follow the links below to understand the phases of the moon.

New moon
Waxing crescent moon
First quarter moon
Waxing gibbous moon
Full moon
Waning gibbous moon
Last quarter moon
Waning crescent moon

Read more: 4 keys to understanding moon phases

Waning crescent moon from Russ Adams in Pike County, Illinois. Thanks, Russ!

Bottom line: A waning crescent moon comes between last quarter moon and new moon.

Check out EarthSky’s guide to the bright planets.

Help EarthSky keep going! Please donate.

from EarthSky http://bit.ly/2WzeRac