Astronomy

[Dreamwoven]

Got posts from Popular Astronomy, so new material is available. Posting separately on this.

The SOCIETY for POPULAR ASTRONOMY
Electronic News Bulletin No. 460 2018 January 7


Here is the latest round-up of news from the Society for Popular Astronomy. The SPA is arguably Britain's liveliest astronomical society, with members all over the world. We accept subscription payments online at our secure site and can take credit and debit cards. You can join or renew via a secure server or just see how much we have to offer by visiting http://www.popastro.com/

[Dreamwoven]

Society for Popular Astronomy:

BRIGHT AREAS ON CERES SUGGEST 'GEO'LOGICAL ACTIVITY

NASA

Since Dawn arrived in orbit around Ceres in 2015 March, scientists have located more than 300 bright areas on Ceres' surface. A new study divides the features into four categories. The first group of bright spots contains the most reflective material on Ceres, which is found on crater floors. The most iconic examples are in Occator Crater, which hosts two prominent bright areas. Cerealia Facula, in the centre of the crater, consists of bright material covering a 10-km-wide pit, within which sits a small dome. East of the centre is a collection of slightly less reflective and more diffuse features called Vinalia Faculae. All the bright areas in Occator Crater are made of salt-rich material, which was probably once mixed in water. Although Cerealia Facula is the brightest area on all of Ceres, it would resemble dirty snow to the human eye. More commonly, in the second category, bright material is found on the rims of craters, streaking down toward the floors. Impacting bodies probably exposed bright material that was already in the sub-surface or had formed in a previous impact event.Separately, in the third category, bright material can be found in the material ejected when craters were formed. The mountain Ahuna Mons gets its own fourth category -- the one instance on Ceres where bright material is not associated with any impact crater. It is probably a cryovolcano, a volcano formed by the gradual accumulation of thick, slowly flowing icy materials; it has prominent bright streaks on its flanks. Over hundreds of millions of years, bright material has mixed with the dark material that forms the bulk of Ceres' surface, as well as debris ejected by impacts. That means that billions of years ago, when Ceres experienced more impacts, the dwarf planet's surface would probably have been peppered with thousands of bright areas.

Why do the different bright areas of Occator seem so distinct from one another? The leading explanation for what happened is that Occator could have had, at least in the recent past, a reservoir of salty water beneath it. Vinalia Faculae, the diffuse bright regions to the northeast of the crater's central dome, could have formed from a fluid driven to the surface by a small amount of gas, similar to champagne surging out of its bottle when the cork is removed. In the case of the Vinalia Faculae, the dissolved gas could have been a volatile substance such as water vapour, carbon dioxide, methane or ammonia. Volatile-rich salty water could have been brought close to Ceres' surface through fractures that connected to the briny reservoir beneath Occator. The lower pressure at Ceres' surface would have caused the fluid to boil off as a vapour. Where fractures reached the surface, the vapour could escape energetically, carrying with it ice and salt particles and depositing them on the surface. Cerealia Facula must have formed by a somewhat different process, given that it is more elevated and brighter than Vinalia Faculae. The material at Cerealia may have been more like an icy lava, seeping up through the fractures and swelling into a dome. Intermittent phases of boiling, similar to what happened when Vinalia Faculae formed, may have occurred during that process, littering the surface with ice and salt particles that formed the Cerealia bright spot. The analyses do not depend on the initial impact that formed Occator. However, the current thinking among Dawn scientists is that when a large body slammed into Ceres, excavating the 92-kilometre-wide crater, the impact may also have created fractures through which liquid later emerged. As Dawn continues the final phase of its mission, in which it will descend to lower altitudes than ever before, scientists hope to continue learning about the origins of the bright material on Ceres and what gave rise to the enigmatic features in Occator.

[Dreamwoven]

Society for Popular Astronomy:

'OUMUMUAMA WAS A NATURAL BODY

Queen's University Belfast

Scientists at Queen's University Belfast have led worldwide investigations into a mysterious object that passed close to the Earth after arriving from deep interstellar space. Since the object was first observed in October, an international team of astronomers has pieced together a profile of the strange visitor, which has been named `Oumuamua. The team measured the way that `Oumuamua reflects sunlight, and found it similar to icy objects covered with a dry crust. That is because `Oumuamua has been exposed to cosmic rays for millions of years, creating an insulating organic-rich layer on its surface. The research suggests that `Oumuamua's dry crust could have protected its icy interior from being vaporised -- even though the object was just 23 million miles from the Sun in September when it flew past. Researchers have discovered that the surface of `Oumuamua is similar to small Solar-System bodies that are covered in carbon-rich ices, whose structure is modified by exposure to cosmic rays. The object was the same colour as some of the icy minor planets that they had been studying in the outskirts of the Solar System. That implies that other planetary systems in our Galaxy contain minor planets like our own. Astronomers have discovered that `Oumuamua is a planetesimal with a well-baked crust that looks a lot like the tiniest worlds in the outer regions of the Solar System, has a greyish/red surface and is highly elongated, probably about the size and shape of the Gherkin skyscraper in London. It is fascinating that the first interstellar object discovered looks so much like a tiny world from our own home system. That suggests that the way our planets and asteroids formed has a lot in common with the systems around other stars.

[Danik 2016]

Society for Popular Astronomy:

BRIGHT AREAS ON CERES SUGGEST 'GEO'LOGICAL ACTIVITY

NASA

Since Dawn arrived in orbit around Ceres in 2015 March, scientists have located more than 300 bright areas on Ceres' surface. A new study divides the features into four categories. The first group of bright spots contains the most reflective material on Ceres, which is found on crater floors. The most iconic examples are in Occator Crater, which hosts two prominent bright areas. Cerealia Facula, in the centre of the crater, consists of bright material covering a 10-km-wide pit, within which sits a small dome. East of the centre is a collection of slightly less reflective and more diffuse features called Vinalia Faculae. All the bright areas in Occator Crater are made of salt-rich material, which was probably once mixed in water. Although Cerealia Facula is the brightest area on all of Ceres, it would resemble dirty snow to the human eye. More commonly, in the second category, bright material is found on the rims of craters, streaking down toward the floors. Impacting bodies probably exposed bright material that was already in the sub-surface or had formed in a previous impact event.Separately, in the third category, bright material can be found in the material ejected when craters were formed. The mountain Ahuna Mons gets its own fourth category -- the one instance on Ceres where bright material is not associated with any impact crater. It is probably a cryovolcano, a volcano formed by the gradual accumulation of thick, slowly flowing icy materials; it has prominent bright streaks on its flanks. Over hundreds of millions of years, bright material has mixed with the dark material that forms the bulk of Ceres' surface, as well as debris ejected by impacts. That means that billions of years ago, when Ceres experienced more impacts, the dwarf planet's surface would probably have been peppered with thousands of bright areas.

Why do the different bright areas of Occator seem so distinct from one another? The leading explanation for what happened is that Occator could have had, at least in the recent past, a reservoir of salty water beneath it. Vinalia Faculae, the diffuse bright regions to the northeast of the crater's central dome, could have formed from a fluid driven to the surface by a small amount of gas, similar to champagne surging out of its bottle when the cork is removed. In the case of the Vinalia Faculae, the dissolved gas could have been a volatile substance such as water vapour, carbon dioxide, methane or ammonia. Volatile-rich salty water could have been brought close to Ceres' surface through fractures that connected to the briny reservoir beneath Occator. The lower pressure at Ceres' surface would have caused the fluid to boil off as a vapour. Where fractures reached the surface, the vapour could escape energetically, carrying with it ice and salt particles and depositing them on the surface. Cerealia Facula must have formed by a somewhat different process, given that it is more elevated and brighter than Vinalia Faculae. The material at Cerealia may have been more like an icy lava, seeping up through the fractures and swelling into a dome. Intermittent phases of boiling, similar to what happened when Vinalia Faculae formed, may have occurred during that process, littering the surface with ice and salt particles that formed the Cerealia bright spot. The analyses do not depend on the initial impact that formed Occator. However, the current thinking among Dawn scientists is that when a large body slammed into Ceres, excavating the 92-kilometre-wide crater, the impact may also have created fractures through which liquid later emerged. As Dawn continues the final phase of its mission, in which it will descend to lower altitudes than ever before, scientists hope to continue learning about the origins of the bright material on Ceres and what gave rise to the enigmatic features in Occator.

It seems that salt is contained in the composition of several celestial bodies.

[Dreamwoven]

Skanska was originally a Swedish company, now a multinational: https://sv.wikipedia.org/wiki/Skanska

[Danik 2016]

That might be interesting too, though I do hope that they don´t bring any martian microbes to the earth:

ExoMars Rover Will Drill Deep Into Mars to Search for Life (Op-Ed)

"Finding past or present microbial life on Mars would without doubt be one of the greatest scientific discoveries of all time. And in just two years' time, there's a big opportunity to do so, with two rovers launching there to look for signs of life – Mars2020 by NASA and ExoMars by the European Space Agency and Roscosmos.

I am helping to develop one of the instruments for the ExoMars rover, which will be Europe's first attempt to land a mobile platform on the red planet. It will also be the first rover to drill into the martian crust to a depth of two metres."
https://www.space.com/39299-exomars-...e-on-mars.html

[Danik 2016]

Society for Popular Astronomy:

'OUMUMUAMA WAS A NATURAL BODY

Queen's University Belfast

Scientists at Queen's University Belfast have led worldwide investigations into a mysterious object that passed close to the Earth after arriving from deep interstellar space. Since the object was first observed in October, an international team of astronomers has pieced together a profile of the strange visitor, which has been named `Oumuamua. The team measured the way that `Oumuamua reflects sunlight, and found it similar to icy objects covered with a dry crust. That is because `Oumuamua has been exposed to cosmic rays for millions of years, creating an insulating organic-rich layer on its surface. The research suggests that `Oumuamua's dry crust could have protected its icy interior from being vaporised -- even though the object was just 23 million miles from the Sun in September when it flew past. Researchers have discovered that the surface of `Oumuamua is similar to small Solar-System bodies that are covered in carbon-rich ices, whose structure is modified by exposure to cosmic rays. The object was the same colour as some of the icy minor planets that they had been studying in the outskirts of the Solar System. That implies that other planetary systems in our Galaxy contain minor planets like our own. Astronomers have discovered that `Oumuamua is a planetesimal with a well-baked crust that looks a lot like the tiniest worlds in the outer regions of the Solar System, has a greyish/red surface and is highly elongated, probably about the size and shape of the Gherkin skyscraper in London. It is fascinating that the first interstellar object discovered looks so much like a tiny world from our own home system. That suggests that the way our planets and asteroids formed has a lot in common with the systems around other stars.

Researchers have discovered that the surface of `Oumuamua is similar to small Solar-System bodies that are covered in carbon-rich ices, whose structure is modified by exposure to cosmic rays. The object was the same colour as some of the icy minor planets that they had been studying in the outskirts of the Solar System. That implies that other planetary systems in our Galaxy contain minor planets like our own.

That is important for the study of other heavenly bodies.

[Dreamwoven]

This EarthSky article is interesting. Especially on Enceladus, a moon of Saturn: http://earthsky.org/space/10-places-...w-beyond-earth

[Dreamwoven]

The Kuiper Belt is interesting for other bodies that are found there. See http://aasnova.org/2016/07/15/new-ob...e-kuiper-belt/.

I have not been able to copy any of this post, except in small pieces. To read more go to the original and check it out.

"What has the search for the hypothetical Planet Nine led to? In the case of this study, the discovery of a collection of new — and puzzling — objects located in the outer reaches of our solar system.

Characterizing the Outer Solar System
The Kuiper belt is a collection of small icy bodies that lies just beyond the orbit of Neptune — but it turns out that Neptune is still a major factor in the shaping of this belt.

Objects in the Kuiper belt fall broadly into two categories: those that orbit between the resonances of Neptune, and those that have been captured into those resonances, likely during Neptune’s outward migration in the past. All of these objects have low or moderate eccentricities and semimajor axes within ~48 AU, making this distance the approximate “edge” of the outer Kuiper belt.

Beyond this distance, objects tend to have much more interesting orbits. These objects have very eccentric or inclined orbits with large semimajor axes and high perihelia (> 40 AU) — and they were likely scattered into these orbits by encounters with Neptune in their past."

[Dreamwoven]

Note that an AU is the distance between the earth and the sun.

[Dreamwoven]

Astronomical Unit: defined as the average distance between the Earth and its star (the sun). This definition can be found here: https://en.wikipedia.org/wiki/Astronomical_unit. The definition is somewhat ethnocentric!

[Danik 2016]

This EarthSky article is interesting. Especially on Enceladus, a moon of Saturn: http://earthsky.org/space/10-places-...w-beyond-earth

A very interesting article, DW. Comparative studies on snow/ice on several celestial bodies.Where there is ice there is water. And maybe the ice/snow layers work as a kind of protection too.

[Danik 2016]

Astronomical Unit: defined as the average distance between the Earth and its star (the sun). This definition can be found here: https://en.wikipedia.org/wiki/Astronomical_unit. The definition is somewhat ethnocentric!

Thanks, DW. I didn´t know that.

[Danik 2016]

Another curious article.Sounds a bit like a spionage story:

Strange Sky Spiral May Come from Secretive SpaceX Zuma Launch

"A pair of spectacular images of an ethereal spiral in the night sky may show the upper stage of a SpaceX Falcon 9 rocket after it launched a secret satellite for the U.S. government on Sunday night (Jan. 7).

The photos, posted on Twitter, show a brilliant spiral that appeared in the night sky shortly after a SpaceX Falcon 9 rocket launched the Zuma satellite on a mystery mission for the U.S. government. Some media reports, citing anonymous government officials, have reported that the Northrop Grumman-built Zuma spacecraft may have failed after it launched into orbit. SpaceX representatives have said their Falcon 9 rocket performed as expected during the Zuma launch. A Northrop Grumman representative said the company cannot comment on the mission due to its classified nature."
https://www.space.com/39338-spacex-z...al-photos.html

[Danik 2016]

Wellcome back, DW!

Some Plants Grow Well in Martian Soil

By: Camille M. Carlisle | January 12, 2018

"NASA and private entrepreneurs are pushing to land people on Mars within the next generation. To survive on Mars, colonists will need a lot of gear, not least of which is food. Since lugging food adds a lot of weight to spacecraft — and packaged food only retains its nutrients for so long, anyway — any would-be Martians will need to grow food on site in To see how terrestrial plants might fare in Martian soil, students at Villanova University last semester conducted the Red Thumbs Mars Garden Project. They obtained simulated Martian soil, made from volcanic basalts similar to those on Mars, and mixed it with other compounds to make it about 90% similar to Martian regolith.

The students focused on nutritious plants, including lettuce, kale, garlic, and potatoes, as well as hops (the business students were looking for inventive ways to make Martian greenhouse products marketable, professor Edward Guinan quipped during his talk January 12th at the American Astronomical Society meeting in Washington, D.C.). They then planted the seedlings in different concentrations of Martian soil in a campus greenhouse rigged for light levels on the Red Planet and let things unfold.order to survive."

http://www.skyandtelescope.com/astro...-martian-soil/

Quite a salad! But Martian soil isn´t Mars!