Space: The Final Frontier

[CaaC (John)+]

4 hours ago, nudge said:

No politics allowed here 

I was going to put this in the Trump thread and was not sure, you can move it if you want, Donald Duck should not infest Space.

[CaaC (John)+]

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It’s blue, but it’s not actually a ring

Scientists solve a 16-year-old cosmic mystery.

The Blue Ring Nebula consists of two expanding cones of gas ejected into space by a stellar merger. Credit: NASA / JPL-Caltech / M Seibert (Carnegie Institution for Science) / K Hoadley (Caltech) / GALEX Team

The so-called Blue Ring Nebula, which has perplexed astronomers for a decade and a half, appears to be the youngest known example of two stars merged.

In a paper in Nature, a team of scientists, including members of the team that first observed a ring around the star TYC 2597-735-1, suggests it is actually the base of a cone-shaped cloud of fluorescing debris formed after a Sun-like star engulfed a smaller companion.

In fact, they say, two cones of material were shot out in the collision, in opposite directions. Because one is pointed directly towards Earth, it appears as a ring.

The event represents the first observation of a rare phase in the evolution of stellar mergers that occurs a few thousand years into the process and is estimated to last thousands to hundreds of thousands of years – a relatively short period on the timescale of cosmic events.

“The merging of two stars is fairly common, but they quickly become obscured by lots of dust as the ejecta from them expands and cools in space, which means we can’t see what has actually happened,” says lead author Keri Hoadley, from California Institute of Technology (Caltech).

The story began in 2004 when scientists with NASA’s then space-based Galaxy Evolution Explorer (GALEX) spotted a large, faint blob of gas. Subsequent observations revealed a thick ring structure within it.

The blob was similar in size to a supernova remnant or a planetary nebula but had a living star at its centre. And while supernova remnants and planetary nebulas radiate in multiple wavelengths outside the UV range, further research showed the Blue Ring Nebula did not.

More than a decade later, scientists and citizen scientists had gathered data from four space telescopes and four ground-based telescopes, as well as historical observations of the star going back to 1895, but were no closer to an answer.

That came, Hoadley says, when they realised that rather than looking for new data they needed new ways to make sense of existing data.

To help make that happen, they called in theoretical astrophysicist Brian Metzger from Columbia University, who develops mathematical and computational models of cosmic phenomena, which can be used to predict how those phenomena will look and behave.

“It wasn’t just that Brian could explain the data we were seeing; he was essentially predicting what we had observed before he saw it,” says Hoadley. “He’d say, ‘If this is a stellar merger, then you should see X’, and it was like, ‘Yes! We see that’.”

The team concluded that the nebula was the product of a relatively fresh stellar merger that likely occurred between a star similar to our Sun and another star only about one-tenth that size. Nearing the end of its life, the bigger star began to swell, creeping closer to its companion. Eventually, the smaller star fell into a downward spiral toward its larger companion.

Along the way, the larger star tore the smaller star apart, wrapping itself in a ring of the debris before swallowing the smaller star entirely. This was the violent event that led to the formation of the Blue Ring Nebula.

The merger launched a cloud of hot debris into space that was sliced in two by the gas disc, and this created two cone-shaped debris clouds.

The Blue Ring Nebula consists of two expanding cones of gas ejected into space by a stellar merger. Credit: NASA / JPL-Caltech / M Seibert (Carnegie Institution for Science) / K Hoadley (Caltech) / GALEX Team

https://cosmosmagazine.com/space/astronomy/its-blue-but-its-not-actually-a-ring/

 

 

Edited November 19, 2020 by CaaC (John)

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‘Fossil galaxy’ found deep in the Milky Way

Astronomers suggest they collided when our galaxy was young.

An all-sky image of the stars in the Milky Way as seen from Earth. The coloured rings show the approximate extent of the stars that came from the fossil galaxy known as Heracles. Credit: Danny Horta-Darrington (LJMU), ESA/Gaia, SDSS

 

Astronomers say they have discovered a “fossil galaxy” hidden in the depths of the Milky Way that may alter thinking on how our galaxy grew into what we see today.

They have named it Heracles, after the hero of Greco-Roman mythology who received the gift of immortality when the Milky Way was created, and say it may have collided with the Milky Way 10 billion years ago when our galaxy was still in its infancy.

The remnants of Heracles account for about one-third of the Milky Way’s spherical halo, the researchers say in a paper in the Monthly Notices of the Royal Astronomical Society, so this newly discovered ancient collision must have been a major event.

That suggests, they add, that our galaxy may be unusual since most similar massive spiral galaxies had much calmer early lives.

“To find a fossil galaxy like this one, we had to look at the detailed chemical makeup and motions of tens of thousands of stars,” says Ricardo Schiavon from Liverpool John Moores University (LJMU) in the UK.

“That is especially hard to do for stars in the centre of the Milky Way because they are hidden from view by clouds of interstellar dust.”

To differentiate Heracles from the original Milky Way, the team used chemical compositions and velocities of stars measured by the Sloan Digital Sky Surveys’ Apache Point Observatory Galactic Evolution Experiment (APOGEE), which takes spectra of stars in near-infrared light.

“Of the tens of thousands of stars we looked at, a few hundred had strikingly different chemical compositions and velocities,” says LJMU’s Danny Horta-Darrington, the paper’s lead author.

“These stars are so different that they could only have come from another galaxy. By studying them in detail, we could trace out the precise location and history of this fossil galaxy.”

Because galaxies are built through mergers of smaller galaxies across time, the remnants of older galaxies are often spotted in the outer halo of the Milky Way, a huge but very sparse cloud of stars enveloping the main galaxy.

But since our galaxy built up from the inside out, finding the earliest mergers requires looking at the most central parts of the Milky Way’s halo, which are buried deep within the disc and bulge.

This computer simulation of a galaxy like the Milky Way moves from 13 billion years ago to today. The main galaxy grows as many small galaxies merge with it. Credit: Video Ted Mackereth based on EAGLE simulations

https://cosmosmagazine.com/space/astronomy/fossil-galaxy-found-deep-in-the-milky-way/

 

 

Edited November 20, 2020 by CaaC (John)

[CaaC (John)+]

@nudge, get your telescope ready and as @MUFC would say "any pics?"  

Edit: Shite, just spotted this below...

They will be too widely separated to fit within the field of view of a telescope but will be visible to the naked eye or through a pair of binoculars.

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Nov. 25: The waxing, gibbous moon will be in conjunction with Mars at 2:46 p.m. EST (1946 GMT). Look for the pair above the eastern horizon after sunset.

The Moon in conjunction with Venus and Jupiter, with the Very Large Telescope in the foreground. Image © Y. Beletsky, ESO, 2009.

The Moon and Mars will make a close approach, passing within 4°27' of each other. The Moon will be 11 days old.

From St Helens, the pair will be visible in the evening sky, becoming accessible around 16:28 (GMT) as the dusk sky fades, 19° above your eastern horizon. They will then reach their highest point in the sky at 20:50, 42° above your southern horizon. They will continue to be observable until around 02:32 when they sink below 8° above your western horizon.

The Moon will be at mag -12.4 in Cetus, and Mars will be at mag -1.3 in Pisces.

They will be too widely separated to fit within the field of view of a telescope but will be visible to the naked eye or through a pair of binoculars.

At around the same time, the pair will also share the same right ascension – called a conjunction.

A graph of the angular separation between the Moon and Mars around the time of closest approach is available here.

The positions of the pair at the moment of closest approach will be as follows:

Object	Right Ascension	Declination	Constellation	Magnitude	Angular Size
The Moon	01h06m20s	+01°56'	Cetus	-12.4	29'27"6
Mars	00h58m50s	+05°59'	Pisces	-1.3	15"4

The coordinates above are given in J2000.0. The pair will be at an angular separation of 131° from the Sun, which is in Scorpius at this time of year.

THE SKY ON 25 NOVEMBER 2020
Sunrise 07:54 Sunset 16:01 Twilight ends 18:07 Twilight begins 05:48	Waxing Gibbous 83% 10 days old	Planets   Rise Culm. Set Mercury 06:33 11:03 15:33 Venus 05:03 10:04 15:05 Moon 14:44 20:51 01:51 Mars 14:13 20:49 03:29 Jupiter 11:43 15:39 19:35 Saturn 11:50 15:51 19:51 All times are shown in GMT.

Source

The circumstances of this event were computed using the DE430 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).

This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.

Related news

14 Oct 2020	–  Mars at opposition
13 Jul 2021	–  Mars at aphelion
20 Sep 2021	–  Mars at apogee
08 Oct 2021	–  Mars at solar conjunction

https://in-the-sky.org/news.php?id=20201125_15_100

 

Edited November 22, 2020 by CaaC (John)

[nudge+]

2 hours ago, CaaC (John) said:

, get your telescope ready and as @MUFC would say "any pics?"  

Edit: Shite, just spotted this below...

They will be too widely separated to fit within the field of view of a telescope but will be visible to the naked eye or through a pair of binoculars

Weather conditions have been too poor lately anyway, cloudy, foggy and raining all the time, can't see shite! 

[CaaC (John)+]

On This Day in Space Archive!

 

 

[Stan]

Didn't know where else to put this but it's fantastic 

 

 

[CaaC (John)+]

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Zooming in on space

Lots of pixels and our second minimoon.

The 20,440-pixel MKID device designed for the new MKID Exoplanet Camera. Credit: UC Santa Barbara

When trying to find things in space, it helps to have technology on your side. And the technology keeps getting better.

A team of US and Japanese scientists and engineers has developed the world’s largest superconducting camera by pixel count (20,440), which they say will enable scientists to directly image exoplanets and discs around bright stars.

It is the first permanently deployed superconducting camera that operates in the optical and near-infrared spectrum, and it runs at a brisk 90 millikelvin – a touch over absolute zero.

Now part of the Subaru Telescope on Maunakea, Hawaii the MKID Exoplanet Camera is so named because it uses Microwave Kinetic Inductance Detectors, which help overcome problems of scattered light associated with even the best adaptive optics systems.

MKIDs also can determine the energy of each photon that hits the detector – allowing scientists to determine a planet’s brightness – and they are fast, reading out data thousands of times per second.

There’s still work to be done, notably on the software and algorithms, but the developers, led by the University of California Santa Barbara, are confident of a bright future. The full story to date is told in a paper to be published in Publications of the Astronomy Society of the Pacific.

Meanwhile, astronomers using a suite of the world’s proven telescopes have characterised only the second known minimoon of Earth, the asteroid now known as 2020 CD3.

It was first discovered in February via the University of Arizona’s Catalina Sky Survey, and such was the excitement that 23 researchers from 14 academic institutions in seven countries joined the quest to find out more. Their findings are published in The Astronomical Journal.

Minimoons are small asteroids temporarily captured into orbit around Earth. Within about a year, they are flung back into interplanetary space. CD3 is about a metre in diameter and came within about 13,000 kilometres of Earth at closest approach.

The first known minimoon, 2006 RH120, was detected 14 years ago. With the Vera C Rubin Observatory scheduled to open in 2023, expect to hear about quite a lot more in the near future.

Three images using different filters obtained by the 8-metre Gemini North telescope on Hawaii’s Maunakea were combined to produce this colour composite of 2020 CD3 (centre, point source). Credit: International Gemini Observatory / NOIRLab / NSF / AURA /G Fedorets

https://cosmosmagazine.com/space/exploration/zooming-in-on-space/

 

[nudge+]

China has successfully launched Chang'e 5 moon sample return mission yesterday! If successful, this 23 day mission will land on the moon, drill two meters below the lunar surface, collect 2 kg of material and bring it back to Earth for research for the first time in 44 years. The main goal is to collect samples that are less than two billion years oldin order to study the late-stage volcanism that shaped the younger parts of the rocky surface we see today.

 

[nudge+]

 

 

[Stan]

Megarocket has started to be assembled in Florida.  

Will first launch in Nov 2021 and target to take people to the moon by Nov 2024  

https://www.bbc.co.uk/news/science-environment-55070302

 

[nudge+]

10 minutes ago, Stan said:

Megarocket has started to be assembled in Florida.  

Will first launch in Nov 2021 and target to take people to the moon by Nov 2024  

https://www.bbc.co.uk/news/science-environment-55070302

 

With the budget cuts, mismanagement and whatnot, I sincerely doubt that. If that does happen, I really hope it does not fail as at this point, there are more red flags about it than in a communist parade.

[CaaC (John)+]

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Shining light on the Sun’s source of power

A new class of neutrinos ends a chapter of physics.

Operators on the installation scaffold mounting the phototubes on the Borexino sphere. Credit: Borexino Collaboration

Scientists working with $AU60 million instrument in Italy have found a new class of neutrinos coming from the Sun that confirms, as has long been theorised, that the Sun burns its nuclear fuel via two different thermonuclear pathways. 

“We have completed a chapter of physics which started more than 80 years ago,” says nuclear physicist Gioacchino Ranucci, a spokesperson for the Borexino Collaboration at the Italian National Institute for Nuclear Physics Gran Sasso Laboratories, where the detection occurred.

Most of the Sun’s energy, Ranucci says, comes from the proton-proton (pp) process, in which colliding hydrogen nuclei (each composed of a single proton) fuse, via a series of steps, into helium. 

But as far back as 1938, it was proposed that the fusion of hydrogen into helium could also be catalysed by carbon, nitrogen and oxygen, in a series of reactions called the CNO cycle. 

Confirming this from Earth, however, requires looking at the neutrinos each produces as a byproduct and distinguishing those from the CNO cycle from those from the pp process – a decades-long challenge.

Neutrinos are subatomic particles with no mass and no charge, moving at nearly the speed of light. They easily pass through ordinary matter, with vast numbers of them sleeting all the way through the Earth every moment.

Occasionally, however, one hits an electron and knocks it free from its parent atom. To spot these rare encounters, neutrino detectors, such as the one in Gran Sasso, have large tanks of fluid lined with sensors that can detect the faint flashes of light that occur when these electrons interact with their surroundings. 

To prevent interference from other types of radiation, such as cosmic rays, these liquid-scintillation detectors are put in shielded vaults and buried underground. 

Artistic rendering of the Borexino stainless steel sphere merged with the image of the Sun. Credit: Maxim Gromov and Borexino Collaboration

Even then it is difficult to keep out stray radiation. “The [new discovery] is the crowning of a relentless years-long effort that has led us to push the liquid-scintillator technology beyond any previously reached limit, and to make Borexino’s core the least radioactive place in the world,” says Marco Pallavicini, of the University of Genoa. 

The pp process and the CNO chain produce the same type of neutrinos. But their neutrinos carry different mixes of energies, and it is by carefully unscrambling these that the Borexino scientists were able to make their find. 

“This is the first-ever direct demonstration that the CNO cycle is actually occurring in the core of the Sun,” Ranucci says. “We complete a picture of how a star works.”

Better yet, his team found, the number of these neutrinos they detected, when compared to those from the pp process, indicates that the CNO cycle contributes about 1% of the Sun’s total energy – just as theory had long predicted.

That is important not just for understanding the Sun, but for understanding other stars because astrophysical theory suggests that for those even as little as 30% more massive than the Sun, the CNO cycle should be their dominant energy source. 

Furthermore, the scientists suggest in their paper in the journal Nature, it may even be possible to refine the neutrino measurements enough to be able to calculate the amount of carbon, nitrogen and oxygen in our Sun’s core – a direct experimental measurement of what astrophysicists call its metallicity (it's content of elements heavier than hydrogen and helium). 

That’s important because it refines not only our understanding of how the Sun produces energy but also how that energy escapes from its interior to eventually warm our planet – a process affected by the amount of heavier elements present in its core.

https://cosmosmagazine.com/space/astrophysics/shining-light-on-the-suns-source-of-power/

 

[CaaC (John)+]

 

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Was Earth once a bit more like Venus?

Researchers create magma to model our old atmosphere.

Artist's impression of a hot, thick CO2-rich atmosphere (left) and present-day Earth. Credit: Tobias Stierli / NCCR PlanetS

The degassing of early Earth’s magma ocean may have produced an atmosphere similar to that found on Venus today – rich in carbon dioxide and relatively poor in nitrogen – new research suggests.

Modelling by a team led by Paolo Sossi from Switzerland’s ETH Zürich indicates that the atmospheric differences between the two planets have more to do with Earth’s mass and its distance from the Sun rather than the respective accretionary histories.

Scientists agree, Sossi says, that Earth was covered entirely by magma 4.5 billion years ago, but it is less clear what the atmosphere was like at the time.

To make their calculations, he and colleagues from France, Australia and the US created their own magma in the laboratory by creating a powder that matched the composition of Earth’s molten mantle and heating it.

Laser-heated aerodynamic levitation furnace used to melt Earth-like compositions.

That required temperatures of around 2000 degrees Celsius, and thus a special furnace that was heated by a laser. The researchers could levitate the magma inside by letting streams of gas mixtures flow around it.

These gas mixtures were plausible candidates for the primaeval atmosphere that influenced ancient magma, they say, and thus, with each mixture of gases that flowed around the sample, the magma turned out a little different.

“The key difference we looked for was how oxidised the iron within the magma became,” Sossi says. When iron meets oxygen, it turns into rust, so when the gas mixture is blown over their magma contained a lot of oxygen, the iron within the magma became more oxidised.

This gave the researchers something they could compare to naturally occurring rocks that makeup Earth’s mantle today.

“What we found was that, after cooling down from the magma state, the young Earth had an atmosphere that was slightly oxidising, with carbon dioxide as its main constituent, as well as nitrogen and some water,” Sossi says.

The surface pressure was much higher – almost 100 times that of today – as was the atmosphere, due to the hot surface. These characteristics made it more similar to the atmosphere of today’s Venus than to that of today’s Earth.

Sossi and colleagues say they draw two main conclusions. The first is that Earth and Venus began with similar atmospheres, but Venus lost its water because it is closer to the Sun and is thus hotter. Earth kept its water, primarily in the form of oceans, which absorbed much of the CO₂ from the air.

The second is that theories on the emergence of life on Earth based on the “Miller-Urey experiment”, in which lightning strikes interact with certain gases (notably ammonia and methane) to create amino acids, are much less likely because the necessary gases were not sufficiently abundant.

https://cosmosmagazine.com/space/astronomy/was-earth-once-a-bit-more-like-venus/

 

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Solar power stations in space could be the answer to our energy needs

It sounds like science fiction: giant solar power stations floating in space that beam down enormous amounts of energy to Earth. And for a long time, the concept – first developed by the Russian scientist, Konstantin Tsiolkovsky, in the 1920s – was mainly an inspiration for writers.

A century later, however, scientists are making huge strides in turning the concept into reality. The European Space Agency has realised the potential of these efforts and is now looking to fund such projects, predicting that the first industrial resource we will get from space is “beamed power”.

Climate change is the greatest challenge of our time, so there’s a lot at stake. From rising global temperatures to shifting weather patterns, the impacts of climate change are already being felt around the globe. Overcoming this challenge will require radical changes to how we generate and consume energy.

Renewable energy technologies have developed drastically in recent years, with improved efficiency and lower cost. But one major barrier to their uptake is the fact that they don’t provide a constant supply of energy. Wind and solar farms only produce energy when the wind is blowing or the sun is shining – but we need electricity around the clock, every day. Ultimately, we need a way to store energy on a large scale before we can make the switch to renewable sources.

Benefits of space

A possible way around this would be to generate solar energy in space. There are many advantages to this. A space-based solar power station could orbit to face the Sun 24 hours a day. The Earth’s atmosphere also absorbs and reflects some of the Sun’s light, so solar cells above the atmosphere will receive more sunlight and produce more energy.

But one of the key challenges to overcome is how to assemble, launch and deploy such large structures. A single solar power station may have to be as much as 10 kilometres squared in area – equivalent to 1,400 football pitches. Using lightweight materials will also be critical, as the biggest expense will be the cost of launching the station into space on a rocket.

One proposed solution is to develop a swarm of thousands of smaller satellites that will come together and configure to form a single, large solar generator. In 2017, researchers at the California Institute of Technology outlined designs for a modular power station, consisting of thousands of ultralight solar cell tiles. They also demonstrated a prototype tile weighing just 280 grams per square metre, similar to the weight of the card.

Recently, developments in manufacturing, such as 3D printing, are also being looked at for this application. At the University of Liverpool, we are exploring new manufacturing techniques for printing ultralight solar cells on to solar sails. A solar sail is a foldable, lightweight and highly reflective membrane capable of harnessing the effect of the Sun’s radiation pressure to propel a spacecraft forward without fuel. We are exploring how to embed solar cells on solar sail structures to create large, fuel-free solar power stations.

These methods would enable us to construct the power stations in space. Indeed, it could one day be possible to manufacture and deploy units in space from the International Space Station or the future lunar gateway station that will orbit the Moon. Such devices could in fact help provide power on the Moon.

The possibilities don’t end there. While we are currently reliant on materials from Earth to build power stations, scientists are also considering using resources from space for manufacturing, such as materials found on the Moon.

Another major challenge will be getting the power transmitted back to Earth. The plan is to convert electricity from the solar cells into energy waves and use electromagnetic fields to transfer them down to an antenna on the Earth’s surface. The antenna would then convert the waves back into electricity. Researchers led by the Japan Aerospace Exploration Agency have already developed designs and demonstrated an orbiter system which should be able to do this.

There is still a lot of work to be done in this field, but the aim is that solar power stations in space will become a reality in the coming decades. Researchers in China have designed a system called Omega, which they aim to have operational by 2050. This system should be capable of supplying 2GW of power into Earth’s grid at peak performance, which is a huge amount. To produce that much power with solar panels on Earth, you would need more than six million of them.

Smaller solar power satellites, like those designed to power lunar rovers, could be operational even sooner.

Across the globe, the scientific community is committing time and effort to the development of solar power stations in space. Our hope is that they could one day be a vital tool in our fight against climate change.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

https://www.space.com/solar-power-stations-in-space-could-be-the-answer-to-our-energy-needs.html

 

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Bayesian statistics and the hunt for ET

Astrobiologists ponder what finding a sign might mean.

Credit: David Wall / Getty Images

One of the goals of the next generation of giant telescopes, now rapidly nearing completion, is to scour the nearby heavens for stars whose planets show signs of life.

If they find even a single such a world, Amedeo Balbi of the University of Rome Tor Vergata and Claudio Grimaldi of the Swiss Federal Institute of Technology Lausanne say, it probably means that the galaxy is teeming with life-bearing worlds.

In fact, the two astrobiologists write in the journal Proceedings of the National Academy of Sciences, such a discovery would indicate that life-bearing worlds may well be more common than pulsars (which are believed to number in the order of 200,000 in the Milky Way galaxy alone).

But if nothing is found, they say, it’s no reason to think we’re alone. It just means there’s no other world with detectable biosignatures close enough for even the best of the upcoming telescopes to detect its biosignatures.

These telescopes include NASA’s James Webb Space Telescope (scheduled for launch in 2021), the ESA’s Atmospheric Remote-sensing Exoplanet Large-survey space telescope (ARIEL, scheduled for launch in 2028), and the ground-based European Extremely Large Telescope (ELT, now under construction on a mountaintop in Chile and expected to be finished in 2025).

Ready for the hunt. The primary mirror on NASA’s new James Webb Space Telescope. Credit: NASA

But while they are all formidable instruments, Balbi says, they won’t be able to ferret out life signs on more than a fairly small number of nearby worlds.

Exactly how many isn’t yet certain. But, he says, “it is safe to say that even with the best telescopes of the next two decades, we will not be able to study more than a few tens of nearby exoplanets with enough detail to look for evidence of life.”

In order to figure out what detecting such a biosignature might mean, he says, he and Grimaldi used a method called “Bayesian statistics” to figure out how one or more such detections (or none) might affect our understanding of how common life is in the Universe.

“Intuitively,” he says, “We expect that if we find evidence of life on a planet orbiting another star, then life must be common in the Universe. Our study tries to put this in rigorous statistical terms.”

“Right now,” he adds, “We only know one inhabited planet, Earth. So, we know basically nothing about the abundance of life in the Universe. Even just one detection of life elsewhere would change things dramatically.”

Not finding anything, however, won’t change our knowledge as strongly.

“The sample we will be able to study is very small compared to the whole galaxy,” he says. “So if we find something, it has a big impact. If we don’t, there is still the possibility that we have not looked at a large enough sample.”

Confusing the picture slightly, he adds, is the idea of panspermia, which posits that life can survive on rocks chipped off of a habitable world in one planetary system and live long enough to fall to the ground in a nearby one, thereby seeding it with life that originated elsewhere.

If so, the distribution of life in the galaxy might be clumpy, meaning that the detection of a biosignature on a nearby exoplanet might simply mean it and Earth life are part of the same clump.

In other words, Balbi says, “We might find ourselves in a region of the galaxy that is more ‘populated’ than others, just because life spread.”

Also, the life signs these telescopes will be seeking don’t mean that if they find them, we’ve found ET. They could equally well mean that all we’ve found is a bunch of bacterial slime.

But, Balbi notes, if the life of any type, even microscopic, proves to be common in the Galaxy, it does up the ante that ET is out there, somewhere, waiting to say hello.

https://cosmosmagazine.com/space/astrobiology/bayesian-statistics-and-the-hunt-for-et/

 

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Losing Arecibo's giant dish leaves humans more vulnerable to space rocks, scientists say

Arecibo was a cornerstone in the campaign to protect Earth from asteroids.

Ignorance may feel like bliss, but preparedness offers better odds of surviving what is to come. And when it comes to planetary defence, ignorance just became a bit more inevitable.

Planetary defence is the art of identifying and mitigating threats to Earth from asteroid impacts. And among its tools is planetary radar, an unusual capability that can give scientists a much better look at a nearby object. Arecibo Observatory in Puerto Rico was one of only a couple such systems on the planet, and that instrument's long tenure is over now after two failed cables made the telescope so unstable that there was no way to even evaluate its status without risking workers' lives, according to the U.S. National Science Foundation (NSF), which owns the site. Instead, it will be decommissioned.

And when it comes to planetary defence, there's nothing like it.

"There's been statements in the media that, 'Oh we have other systems that can kind of replace what Arecibo is doing,' and I don't think that's true," Anne Virkki, who leads the planetary radar team at Arecibo Observatory, told Space.com. "It's not obsolete and it's not easily replaceable by other existing facilities and instruments."

Related: Losing Arecibo Observatory would create a hole that can't be filled, scientists say

Planetary defence begins with spotting as many near-Earth asteroids as possible — nearly 25,000 to date, according to NASA — and estimating their sizes and their orbits around the sun. Arecibo never played a role in discovering asteroids; that task is much more easily completed by a host of telescopes that see large swaths of the sky in visible and infrared light and are able to catch the sudden appearance of a bright, fast-moving dot between the stars, telescopes like the PanSTARRS observatory in Hawaii. With those first observations, the smallest asteroids and those that stay far from Earth can be safely labelled and more or less forgotten.

But larger asteroids with orbits that might bring them too close for comfort get an additional study, and often, that work has been Arecibo Observatory. The facility sported a powerful radar transmitter that could bounce a beam of light off an object in Earth's neighbourhood. Then, the observatory's massive radio dish could catch the echo of that signal, letting scientists decipher precise details about an asteroid's location, size, shape and surface.

The same telescopes that identify asteroids in the first place can also give scientists the data they need to track a space rock's orbit, but when planetary radar can spot the object, it completes the same work more quickly.

https://www.space.com/arecibo-observatory-loss-for-planetary-defense-asteroids

 

Edited November 30, 2020 by CaaC (John)

[CaaC (John)+]

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A new and detailed atlas of the skies

Telescope maps three million galaxies in 300 hours.

A new radio telescope in outback Western Australia has just created an atlas of the southern sky in record-breaking time, demonstrating that detailed all-sky surveys can now be done in weeks instead of years.

Over just 300 hours, CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP) mapped three million galaxies, one million of which we’d never seen before.

The survey covered 83% of the entire sky by stitching together 903 individual wide-field images – an impressive feat considering that existing survey telescopes need tens of thousands of images to achieve the same coverage. 

RACS is also twice as sensitive as previous comparable surveys. Each image contains 2000-4000 objects – mostly distant radio-bright galaxies, but also objects within the Milky Way-like supernova remnants and pulsars.

The initial results of the survey, called the Rapid ASKAP Continuum Survey (RACS), are published in the journal Publications of the Astronomical Society of Australia. 

“For the first time, ASKAP has flexed its full muscles, building a map of the Universe in greater detail than ever before, and at record speed,” says lead author and CSIRO astronomer David McConnell. “We expect to find tens of millions of new galaxies in future surveys.”

Such broad snapshots of the sky will help astronomers statistically analyse huge populations of galaxies and thus answer questions about their origins, dynamics and evolution.

“This census of the Universe will be used by astronomers around the world to explore the unknown and study everything from star formation to how galaxies and their supermassive black holes evolve and interact,” McConnell says.

ASKAP’s key feature is its wide field of view, allowing it to take detailed panoramic images. Most radio receivers can only see a small part of the sky, so performing large-scale surveys is time-consuming. But by increasing the number of receivers and spacing them over a large area, radio telescopes can stitch together dozens of signals and therefore “see” a larger patch of sky. 

ASKAP comprises 36 antennas spread over of six kilometres in a remote, radio-quiet area. These antennas feed massive amounts of data to a supercomputing facility 700 kilometres away in Perth, which then reconstructs the images. 

With many receivers working as one, the telescope has a 30-square-degree view of the sky – about as large as the Southern Cross, and about 40 times larger than the area viewed by a traditional radio telescope.

This survey, RACS, will likely replace major existing all-sky surveys as a first reference point for astronomers, providing a baseline comparison for future studies to refer back to and determine what has changed.

But this survey was just a test. ASKAP’s main scientific program will launch in 2021, performing several more in-depth surveys over five years. 

“Future ASKAP work, the surveys for which the telescope was designed, will take longer and see more deeply into the universe,” says McConnell.

These results will also be used to design projects for the Square Kilometre Array (SKA) – a massive, continent-spanning astronomy project that will become the world’s biggest radio telescope. Its low-frequency node will be hosted by the Murchison Radio-astronomy Observatory, where ASKAP is currently picking up whisper-quiet radio signals from the distant universe.

https://cosmosmagazine.com/space/astronomy/new-and-detailed-atlas-of-the-skies/

 

 

[nudge+]

China is streaming Chang'e 5 Moon landing live, the landing expected in about one hour!

Mirrored stream on youtube:

 

[CaaC (John)+]

3 minutes ago, nudge said:

China is streaming Chang'e 5 Moon landing live, the landing expected in about one hour!

Mirrored stream on youtube:

 

I hope it goes well and they land ok.

[CaaC (John)+]

 

Edited December 1, 2020 by CaaC (John)

[nudge+]

They cut all livestreams shortly before the landing sequence was supposed to start. Wankers  Good to see the landing was successful, though, and hopefully the sample collection part as well as return to Earth will go well too.

 

Meanwhile, Hayabusa2 is now 5 days away from returning the Ryugu asteroid samples to Earth. Expected timing (in Japan Standard Time, so need to subtract 9 hours for GMT):

December 5, 14:00 - 15:00: capsule separation
Dec. 5, 15:00 - 17:00: orbit change for spacecraft departure
Dec. 6, 02:00 - 03:00: capsule landing

 

 

In other news, Starship SN8 15km test flight has been aimed for Thursday!

[CaaC (John)+]

3 minutes ago, nudge said:

They cut all livestreams shortly before the landing sequence was supposed to start. Wankers  Good to see the landing was successful, though, and hopefully the sample collection part as well as return to Earth will go well too.

Aye, I wonder why? they might have a Chinese Man in the Moon who has been living there for years and we did not know anything about it.