Astronomical Stargazer Thread

[savantu]

Yeah, noticed that.

According to the paper it must weight between 5 and 20 Earths. Also one of the variables is the age ( assumed 4,5 Billion years ).

[Mobius]

I'm not sure if the plane of the planets orbit not perfectly aligned with the axis of the sun is crucial in this. We were told that if the earth was not locked with the moon it's axis might wander off tilt. If that is possible then the sun which is not locked to any other body and which has ejected quite a lot of mass and energy over it's life might not have done it all equally over time. And that might have made it's axis wander a bit.

 

But if there is a planet or two way way out there it might be a good thing for space travel. There might be stepping stones to the next star or stars. We might not get there right away but bases could be established around planets. Travel might take multiple generations. But it could eventually happen. Proxima centauri might have a planet or two way way out from it as well.

Edited October 25, 2016 by Mobius

[Ivanhoe]

If nothing else, we can use them for mining/penal colonies.

[Panzermann]

An unexplained 'void' appears to be pushing the Milky Way through the Universe at 2 million km/h

 

We're fleeing from a mysterious 'dead zone'.

BEC CREW 31 JAN 201

 

You cant feel it , but our planet is orbiting the Sun at speeds of roughly 100,000 km/h (62,000 mph), and something is making our Milky Way galaxy move through the Universe at more than 2 million km/h (1.2 million mph). Thats 630 km per second, and now scientists might have finally figured out why.

In front of us, there's a dense supercluster of galaxies some 650 million light-years away called the Shapley Concentration , and it's pulling us towards it. Behind us, scientists have found evidence of a previously unknown region of space that's almost entirely devoid of galaxies, and it's pushing us away with incredible force.

Cosmologist Yehuda Hoffman from Hebrew University in Israel and his team have constructed a new 3D map of our nearest galaxies, and in it, theyve revealed this mysterious 'dead zone' for the first time, and dubbed it the Dipole Repeller.

As you can see in the animation below, were stuck in the middle of the two, as the low-density Dipole Repeller pushes the Milky Way away from it, and the super-dense Shapley Concentration drags us towards it:

 

(video)

 

"By 3D mapping the flow of galaxies through space, we found that our Milky Way galaxy is speeding away from a large, previously unidentified region of low density. Because it repels rather than attracts, we call this region the Dipole Repeller,"

Hoffman explains to Victoria Woollaston at Wired.

"In addition to being pulled towards the known Shapley Concentration, we are also being pushed away from the newly discovered Dipole Repeller. Thus it has become apparent that push and pull are of comparable importance at our location."

In the past, researchers have suggested that a very low-density region of space could be lurking behind our galaxy, because while the Shapley Concentration is incredibly massive, on its own, it can't explain that speeds that the Milky Way is travelling.

And that really says something, because the Shapley Concentration is the largest known concentration of matter in the local Universe - a region of space that's approximately 1 billion light-years in radius.

The only problem is, we can barely even detect a planet that's 4.25 light-years away, let alone find something that's millions of light-years away, so researchers have struggled to fit that piece of the puzzle together.

"There was a hint of the void from studies of the distribution of rich clusters of galaxies that emit X-rays, discussed in articles over a decade ago," one of the team, Brent Tully from the University of Hawai'i, says in a press statement . "But the statistics were not sufficient to be convincing."

But now Hoffman and his team have figured out how measurements from more than 8,000 nearby galaxies, taken from an array of observatories, including the Hubble Space Telescope, fit into our cosmic neighbourhood, and these movements give us the first real evidence of the great Dipole Repeller.

All those forces combined look a little something like this:

 

(image)

 

 

Oddly enough, according to data from the Cosmic Microwave Background - the 'afterglow' of the Big Bang - these two forces appear to be pushing and pulling us with an equal amount of force, and they sit in front and behind the Milky Way on the same axis .

Now that we have the first real evidence that something as vast and empty as the Dipole Repeller is lurking behind the Milky Way and our neighbouring galaxies, the next step is for researchers to try and confirm its existence.

The other possibility is that this region could be not one, but a whole fleet of superclusters and voids , all working to buffet us away, as another, more massive supercluster draws us in.

As Hoffman told Ian Sample at The Guardian , "Its a story of love and hate, attraction and repulsion."

The research has been published in Nature Astronomy.

http://www.sciencealert.com/an-unexplained-void-is-pushing-the-milky-way-through-the-universe-at-2-million-km-h

[Ssnake]

I wonder if that Dipol Repeller is a manifestation of still ongoing spacetime inflation.

[Mobius]

I wonder if that Dipol Repeller is a manifestation of still ongoing spacetime inflation.

Maybe there's such a thing as negative matter. Something that repels ordinary matter as it has negative mass.

This is not anti-matter which has positive mass but cancels ordinary matter but releases energy when it collides with ordinary matter.

In which case the amount of energy required to push the two masses together would be equal to the amount released by their collision. Giving a net 0 for the whole system.

 

Or it could be a region of space that has a high expansion rate.

Edited February 2, 2017 by Mobius

[Josh]

Seems to be related to the universe expanding and 'dark energy'. Or that perhaps gravity itself is a lot more complicated than we thought and we're only looking at it from one side/perspective. Unfortunately things we will likely not determine in our lifetime.

[MiloMorai]

Mobius, How Big Is the Universe? Worth watching.

 

http://docur.co/documentary/how-big-is-the-universe

 

Touches on dark matter and dark energy.

Edited February 2, 2017 by MiloMorai

[Corinthian]

Could be galaxies just running away in horror from Azathoth....

[Mobius]

Mobius, How Big Is the Universe? Worth watching.

 

http://docur.co/documentary/how-big-is-the-universe

 

Touches on dark matter and dark energy.

That is old news. Plus it is wrong. It is about 13.8billion years old so if static the visible universe would be 13.8 billion light years in radius not diameter. But it is expanding so it is a lot bigger. Google says the visible universe is 91 billion LY in diameter. The actual size is unknown.

[Edit] Apparently the person writing the text did view the video as it has the correct radius in it.

Edited February 2, 2017 by Mobius

[DB]

And so it seems that a new homeworld for Scaninavians has been found.

 

http://www.bbc.co.uk/news/science-environment-39521344

 

An atmosphere of super-heated steam*. Bring your own birch twigs.

 

 

*Meh, might also be methane

[toysoldier]

And so it seems that a new homeworld for Scaninavians has been found.

 

http://www.bbc.co.uk/news/science-environment-39521344

 

An atmosphere of super-heated steam*. Bring your own birch twigs.

 

 

*Meh, might also be methane

[Panzermann]

http://www.eso.org/public/unitedkingdom/news/eso1715/?lang

 

eso1715 — Organisation Release
Secondary Mirror of ELT Successfully Cast
Largest convex mirror blank ever created

22 May 2017

 

The casting of the secondary mirror blank for ESO’s Extremely Large Telescope (ELT) has been completed by SCHOTT at Mainz, Germany. The completed mirror will be 4.2 metres in diameter and weigh 3.5 tonnes. It will be the largest secondary mirror ever employed on a telescope and also the largest convex mirror ever produced.

ESO’s 39-metre Extremely Large Telescope (ELT) will be the largest telescope of its kind ever built when it achieves first light in 2024. A new milestone has now been reached with the casting of the telescope’s secondary mirror (M2), which is larger than the primary mirror of many of today’s research telescopes.

The mirror blank is the cast block of material — in this case Zerodur® glass-ceramic [1] — that will then be ground and polished to produce the finished mirror. In January 2017, ESO awarded SCHOTT the contract to manufacture the M2 mirror blank (eso1704). ESO has enjoyed a fruitful collaboration with SCHOTT, who also produced the 8.2-metre meniscus main mirrors for the Very Large Telescope at ESO’s Paranal Observatory (ann12015). A manufacturer of exceptional astronomical products to a very high standard, SCHOTT has already delivered the blanks of the deformable thin shell mirrors that will make up the ELT’s quaternary mirror, M4 (ann15055), and will also provide the blank of the tertiary M3 mirror.

The blank of the secondary mirror now has to go through a slow cool-down, machining and heat treatment sequence over the next year. It will then be ready to be ground to precisely the right shape and polished. The French company Safran Reosc will carry this out, along with additional testing (ann16045). The blank will be shaped and polished to a precision of 15 nanometres (15 millionths of a millimetre) across the entire optical surface.

When completed and installed, the M2 mirror will hang upside down above the telescope’s huge primary mirror and forms the second element of the ELT’s novel five-mirror optical system. The mirror is strongly curved and aspheric and is a major challenge to make and test.
Notes

[1] Originally developed for astronomical telescopes in the late 1960s, Zerodur® has almost no thermal expansion even when subjected to large temperature fluctuations, is highly chemically resistant, and can be polished to a high standard of finish. Many telescopes with Zerodur® mirrors have been operating reliably for decades, including ESO's Very Large Telescope in Chile.
More information

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.
Links

SCHOTT website
Safran Reosc
ELT website

 

 

 

more details on how it all works: http://spie.org/newsroom/4191-equipping-the-european-extremely-large-telescope

 

 

 

Telescopes have come a long way since Galileo.

Edited May 22, 2017 by Panzermann

[Panzermann]

Einstein strikes again. This time with gravitation lenses.

 

https://youtu.be/3Hkz4Z94Lrk&autoplay=0

 

Astronomers measure the mass of a star—thanks to an old tip from Einstein

By Daniel Clery

Jun. 7, 2017 , 11:15 AM

Weighing a star is hard. In fact, binary stars are the only ones scientists can directly gauge, because their orbits around each other reveal their masses. Now, a team of astronomers has succeeded in measuring the mass of an isolated star using a technique first suggested by Albert Einstein in 1936. The method exploits the fact that a large mass, like a star, can bend the path of light. Although the effect is tiny, measuring the deflection can reveal the mass of the light-bending star.

“This is a really elegant piece of work they’ve done,” says astronomer Martin Barstow of the University of Leicester in the United Kingdom, “and a nice echo of a century of general relativity.”

Astronomers have seen many examples of gravity-bending light, including galaxies distorting images of even more distant ones, sometimes stretching them out into circular “Einstein rings.” In our own galaxy, when one star passes in front of another, astronomers see a brief brightening of the more distant one as the nearer star acts as a lens, bending more of its passing rays toward Earth. This effect, known as gravitational microlensing, has been used to detect exoplanets and search for dark matter, black holes, and brown dwarfs.

But Einstein also predicted that if the source of the light and light-bending star are not in exact alignment, the bending will cause the source star to appear to move when viewed from Earth. The size of that shift tells scientists the light-bending star’s mass. The effect is so tiny and the likelihood of such a near-alignment so rare, Einstein thought it could never be done.

But a team of astronomers from the United States, the United Kingdom, and Canada had a hunch that the keen-eyed view of the Hubble Space Telescope might be able to detect such a shift. They started by looking for stars that might be coming into alignment, and found that Stein 2051 B—a white dwarf just 18 light-years from Earth—was due to pass almost directly in front of another star in March 2014. When it did, the team captured the slightest shifts in position of the background star. That shift let the team calculate that Stein 2051 B’s mass is about two-thirds the mass of the sun, 0.675 solar masses, they report today in Science.

But this was more than just a skillful demonstration of a new technique. Stein 2051 B is something of an enigma for specialists in white dwarfs, the husks left behind when stars have burned up all their fuel. (This fate awaits 97% of stars, including the sun.) From observations of its size, temperature, and the light it emits, researchers had estimated that Stein 2051 B was a particular variety of white dwarf that should weigh about 0.67 solar masses. But, using the method to measure mass through binary stars, other researchers had paired it with another nearby star, Stein 2051 A, and had calculated a weight of just 0.5 solar masses. The latest calculation puts Stein 2051 B’s mass exactly where it should be, and it also casts doubt on the idea that A and B are actually a binary pair. “It’s a nice addition to our understanding of white dwarf composition,” Barstow says.

Astronomer Markus Hundertmark of the University of Heidelberg in Germany says that simply the detection of such a shift would have deserved publication in its own right. “Measuring the mass of a nearby white dwarf seems to make the result even better, and at first glance it is a surprising discovery.”

The technique’s application seems limited at the moment, because the near-alignment of stars is so rare, but that will change next year when the second star catalog from the European Space Agency’s Gaia satellite is released, giving exact positions and motions of many thousands of stars. “It’s likely we’ll find many more examples to pursue,” Barstow says. The new result “seems to be a most curious effect,” says team member Martin Dominik of the University of St. Andrews in the United Kingdom, but it will “turn into a quite useful astrophysical technique sooner rather than later.”

Posted in:

• Space

DOI: 10.1126/science.aan6939

 

 

http://www.sciencemag.org/news/2017/06/astronomers-measure-mass-star-thanks-old-tip-einstein

Edited June 8, 2017 by Panzermann

[Ivanhoe]

And so it seems that the original homeworld for Scandinavians has been found.

 

http://www.bbc.co.uk/news/science-environment-39521344

 

An atmosphere of super-heated steam*. Bring your own birch twigs.

 

 

*Meh, might also be methane

 

FIFY. twice.

[mnm]

Might also be methane? That's a Chuck-Norris-epic fart.

[Panzermann]

The wOW signal disenchanted. Seems like it was just some comet flying past.

 

Wow! mystery signal from space finally explained

June 7, 2017 by Bob Yirka

 

(Phys.org)A team of researchers with the Center of Planetary Science (CPS) has finally solved the mystery of the "Wow!" signal from 1977. It was a comet, they report, one that that was unknown at the time of the signal discovery. Lead researcher Antonio Paris describes their theory and how the team proved it in a paper published in the Journal of the Washington Academy of Sciences.

Back in August of 1977, a team of astronomers studying radio transmissions from an observatory at Ohio State called the "Big Ear" recorded an unusual 72-second signalit was so strong that team member Jerry Ehman scrawled "Wow!" next to the readout. Since that time, numerous scientists have searched for an explanation of the signal, but until now, no one could offer a valid argument. Possible sources such as asteroids, exo-planets, stars and even signals from Earth have all been ruled out. Some outside the science community even suggested that it was proof of aliens. It was noted that the frequency was transmitted at 1,420 MHz, though, which happens to be the same frequency as hydrogen.

The explanation started to come into focus last year when a team at the CPS suggested that the signal might have come from a hydrogen cloud accompanying a cometadditionally, the movement of the comet would explain why the signal was not seen again. The team noted that two comets had been in the same part of the sky that the Big Ear was monitoring on the fateful day. Those comets, P/2008 Y2(Gibbs) and 266/P Christensen had not yet been discovered. The team then got a chance to test their idea as the two comets appeared once again in the night sky from November 2016 through February of 2017.

 

The team reports that radio signals from 266/P Christensen matched those from the Wow! signal 40 years ago. To verify their results, they tested readings from three other comets, as well, and found similar results. The researchers acknowledge that they cannot say with certainty that the Wow! signal was generated by 266/P Christensen, but they can say with relative assurance that it was generated by a comet.

Explore further: Report suggests famous radio telescope signal was caused by comets

More information: Hydrogen Line Observations of Cometary Spectra at 1420 MHZ , Journal of the Washington Academy of Sciences, http://planetary-science.org/research/the-wow-signal/(Paper PDF)

ABSTRACT

In 2016, the Center for Planetary Science proposed a hypothesis arguing a comet and/or its hydrogen cloud were a strong candidate for the source of the "Wow!" Signal. From 27 November 2016 to 24 February 2017, the Center for Planetary Science conducted 200 observations in the radio spectrum to validate the hypothesis. The investigation discovered that comet 266/P Christensen emitted a radio signal at 1420.25 MHz. All radio emissions detected were within 1° (60 arcminutes) of the known celestial coordinates of the comet as it transited the neighborhood of the "Wow!" Signal. During observations of the comet, a series of experiments determined that known celestial sources at 1420 MHz (i.e., pulsars and/or active galactic nuclei) were not within 15° of comet 266/P Christensen. To dismiss the source of the signal as emission from comet 266/P Christensen, the position of the 10-meter radio telescope was moved 1° (60 arcminutes) away from comet 266/P Christensen. During this experiment, the 1420.25 MHz signal disappeared. When the radio telescope was repositioned back to comet 266/P Christensen, a radio signal at 1420.25 MHz reappeared. Furthermore, to determine if comets other than comet 266/P Christensen emit a radio signal at 1420 MHz, we observed three comets that were selected randomly from the JPL Small Bodies database: P/2013 EW90 (Tenagra), P/2016 J1-A (PANSTARRS), and 237P/LINEAR. During observations of these comets, we detected a radio signal at 1420 MHz. The results of this investigation, therefore, conclude that cometary spectra are detectable at 1420 MHz and, more importantly, that the 1977 "Wow!" Signal was a natural phenomenon from a Solar System body.

https://phys.org/news/2017-06-wow-mystery-space.html

the paper:

http://planetary-science.org/wp-content/uploads/2017/06/Paris_WAS_103_02.pdf

https://regmedia.co.uk/2017/06/09/wow.pdf

 

 

though in this reddit another scientist refutes: https://www.reddit.com/r/Astronomy/comments/6ganha/no_the_wow_signal_was_probably_not_caused_by/

Edited June 17, 2017 by Panzermann

[Panzermann]

https://www.nasa.gov/feature/jpl/nasa-s-juno-spacecraft-spots-jupiter-s-great-red-spot

 

Jupiter probe Juno pictures:

 

 

 

NASA crowdsoursces the postprocessing: https://www.missionjuno.swri.edu/junocam/processing

 

 

beautiful to look at.

 

 

[mnm]

Jeeeeesus! A Dem spy satellite overflew the FFZ and took these!

[Panzermann]

Are Astronomers on the Verge of Finding an Exomoon?

It would be a huge discovery, but until they train the Hubble on a possible candidate, they won't know for sure—so stay tuned

• By Alex Teachey on July 27, 2017

For years I have been fascinated by the search for exomoons—that is, moons orbiting planets in other star systems. These worlds are exciting for a whole host of reasons: they could tell us a great deal about the processes that formed our solar system and others, and whether we share a common formation history with the estimated hundreds of billions of planets in the Milky Way. There's reason to think moons may play an important role in the habitability of their host planets, as some scientists think our Moon has influenced the evolution of life on Earth. And of course, if moons are habitable in their own right, they stand to expand dramatically the amount of real estate in the Universe where life could arise and flourish. The moons in our Solar System are truly remarkable worlds, astonishingly different from one another, and there's every reason to think exomoons could be equally diverse and exotic.


But so far, no one in the scientific community has been able to produce an unambiguous detection of an exomoon. It's not for lack of trying; there are a handful of us around the world actively seeking these objects, and some have dedicated many years of work to the problem. But exomoons are spectacularly tricky to find. They tend to be much smaller than planets, making their transits—small dips in the intensity of the starlight as they pass in front of the star from our point of view—quite shallow, and "lost in the noise." And every time their host planet transits, the moons show up in a different place, making them particularly difficult to detect. Ingenious indirect methods, like looking for the moons' gravitational influence on their host planet, are now routinely employed as part of the search. But this work has been computationally demanding and requires exceptionally careful analysis.


Even so, I've long felt that the first genuine detection of an exomoon is right around the corner, and I have been thrilled to participate in this race. It's been my great privilege working as a graduate student here at Columbia under my advisor, David Kipping, who has been one of the pioneers in this field.


This morning David and I put out a paper on the arXiv that represents the culmination of years of work searching for the signature of exomoons in the population of stars examined by the Kepler Mission. After carefully analyzing an ensemble of the highest quality planetary transit signals, we have determined that exomoons appear to be quite rare in the inner regions of star systems (regions of space close to the host star). This finding was both remarkable and, frankly, a bit disappointing.

We had hoped and expected to see a significant moon signal in the data, showing us for the first time that moons really are common elsewhere in the galaxy, and that these worlds could be ripe for future observation. Instead we found that the moons we seek are not present in any significant way in the data, meaning that they will remain elusive for the time being, likely hiding in the outer regions of these star systems where Kepler was unable to gather much data. This is a fascinating result on its own, but we had hoped for something else. That's the way science goes, though: you have to follow the facts wherever they lead you.


In any case, there was another result in our paper that may make a considerably larger splash, which you may have even read about in the news, or soon will: We announced our identification of a single exomoon candidate, indeed the strongest candidate we've seen in the five year history of the Hunt for Exomoons with Kepler (HEK) collaboration. The system, Kepler-1625 b, has withstood a host of preliminary tests aimed at ruling out the presence of a moon, and our proposal to observe this system with the Hubble Space Telescope was recently accepted. We are thrilled to get the chance to observe with Hubble, and hope that the observation will confirm our suspicion unambiguously that this is a genuine exomoon detection, which would be the first of its kind.


But we want to make it very clear what this is, and what it isn't. At this point what we have is an exomoon candidate, which is very different from an exomoon detection. While we are optimistic about this candidate, and certainly hope to be credited with the discovery of the exomoon if that is in fact what it is, it remains simply a candidate. Furthermore, we require the follow-up observation on Hubble precisely because we feel the data from Kepler are simply inconclusive. The evidence is tantalizing, but it's just not enough to claim a discovery at this point.

And because a discovery of this sort would be a big deal, we have proceeded so far with an abundance of caution, as we have seen so many times how a sensational scientific discovery announced in the media can evaporate under further scrutiny. Let's be clear: we're not just trying to save ourselves from embarrassment; the announcement and subsequent retraction of potentially ground-breaking results has the effect of eroding public trust in science over time, and we are chiefly concerned with not contributing to that problem.


So why did we put out our paper online now, before a proper peer review and the Hubble observation on which this discovery hinges? Well, it turns out all Hubble observing proposals are publicly available online even before the observation is made, and we found out that at least one media outlet was going to publish the fact that we will be observing our exomoon candidate with Hubble. It remains to be seen how much attention this will get, but we worried that getting the public excited about this object before we really know much of anything for sure is just bad for science. And of course we also worried that it would be very easy for another scientist to come along and try to claim the discovery of this moon using what we feel is really insufficient data. To avoid this, and to be absolutely clear on what we've done and what's left to do, we put out our paper in its current form, which is submitted, but not yet accepted, to the Astrophysical Journal.


Peer review is a critical part of the scientific process, and we are not terribly comfortable putting out our results before they have been examined by a qualified referee. Unfortunately, we feel the circumstances have forced us to make our results freely available to the public before such a review, so that everyone may see for themselves what we are claiming and what we are not. While David and I are both big proponents of engaging with the public and boosting interest in the incredible things happening every day in astronomy, we have serious concerns about the potential for sensational headlines misleading the public into thinking a discovery has been made when it is really too early to say that for sure.


The irony is not lost on me that I'm writing this blog post saying we don't want this to get too much media attention. But I hope I've been able to state our position clearly. And when we've got something real, we'll let you know!

 

 

https://blogs.scientificamerican.com/observations/are-astronomers-on-the-verge-of-finding-an-exomoon/

 

 

Maybe an extrasolar moon. finding exoplanets is already hard as it can be. Moons are much smaller.

[mnm]

Astronomy sure took a big turn when Louis Armstrong landed on the moon!

[Marek Tucan]

Perseids coming close, so I guess I know which weekend will be guaranteed cloudy Though if the weather looks nice, might just pack my sleeping bag and go watch someplace further away from Paris...

[Ssnake]

Astronomy Astrology sure took a big turn when Louis Armstrong landed on discovered the moon!

 

FIFY.

[mnm]

Poor Satchmo, all the trouble he took to get his trumpet to the moon and nobody could hear him play.

[sunday]

Some possible Buddhist aphorism here.