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First Observation of an Interstellar Visitor

Started by Recusant, October 28, 2017, 05:21:38 AM

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Tank

If religions were TV channels atheism is turning the TV off.
"Religion is a culture of faith; science is a culture of doubt." ― Richard P. Feynman
'It is said that your life flashes before your eyes just before you die. That is true, it's called Life.' - Terry Pratchett
Remember, your inability to grasp science is not a valid argument against it.

AngelOfDeath

#16

oh yea.  the ultimate cold shoulder  ;D

Recusant

Apparently not a peep was heard from `Oumuamua.

QuoteNo alien signals have been detected from an interstellar, cigar-shaped space rock discovered travelling through our Solar System in October, researchers listening for evidence of extraterrestrial technology said Thursday.

The object, dubbed Oumuamua, was spotted by several Earthly telescopes two months ago.

Given its weird trajectory, surprised researchers immediately concluded it was from beyond our planetary system—the first interstellar object ever identified in our midst.

The rock is thought to be about 400 metres (1,300 feet) long, and thin—only about 40 m wide, a never-before-seen shape for an asteroid.

After its discovery was announced last month, a project called Breakthrough Listen, dedicated to finding signs of extraterrestrial intelligence, said it would study the rock for artificial signals.

"No such signals have been detected" by its network of telescopes, the project said Thursday, adding: "the analysis is not yet complete".

[Continues . . .]

Its surface appearance is a fairly close match to objects found in our own solar system.

"Alien object 'Oumuama was a natural body visiting from another solar system" | PhysOrg

QuoteScientists at Queen's University Belfast have led worldwide investigations into a mysterious object that passed close to Earth after arriving from deep interstellar space.Since the object was spotted in October, Professor Alan Fitzsimmons and Dr Michele Bannister from the School of Mathematics and Physics at Queen's University have led an international team of astronomers to piece together a profile of the strange visitor, which has been named `Oumuamua.

The team was made up of researchers from elsewhere in the UK, the US, Canada, Taiwan and Chile and in total seven researchers from Queen's were involved.

Professor Alan Fitzsimmons headed up a team which measured the way that `Oumuamua, reflects sunlight, and found it similar to icy objects covered with a dry crust. This is because `Oumuamua has been exposed to cosmic rays for millions, or even billions, of years, creating an insulating organic-rich layer on its surface.

The research, which has been published this week in Nature Astronomy, 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 our sun in September when it zipped past.

Professor Alan Fitzsimmons commented: "We 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.

"We have also found that a half-metre thick coating of organic-rich material could have protected a water-ice-rich comet-like interior from vaporizing when the object was heated by the sun, even though it was heated to over 300 degrees centigrade."

[Continues . . .]

"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Magdalena


"I've had several "spiritual" or numinous experiences over the years, but never felt that they were the product of anything but the workings of my own mind in reaction to the universe." ~Recusant

xSilverPhinx

I am what survives if it's slain - Zack Hemsey


Magdalena


"I've had several "spiritual" or numinous experiences over the years, but never felt that they were the product of anything but the workings of my own mind in reaction to the universe." ~Recusant

Recusant

A summation of current knowledge about 'Oumuamua; the only newish thing I noticed is the note on a paper arguing that this observation implies that there is a very large number of these interstellar objects rattling around the galaxy.

'Update on an Interstellar Asteroid'

QuoteSince 'Oumuamua's discovery, scientists have been gathering as many observations of this body as possible before it vanishes into the distance. Simultaneously, theorists have leapt at the opportunity to explain its presence and the implications its passage has on our understanding of our surroundings. Here we present just a few of the latest studies that have been published on this first detected interstellar asteroid — including several timely studies published in our new journal, Research Notes of the AAS.

[Continues . . .]
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Recusant

A visitor that apparently came and stayed:

"First interstellar immigrant discovered in the solar system" | ScienceDaily

QuoteA new study has discovered the first known permanent immigrant to our Solar System. The asteroid, currently nestling in Jupiter's orbit, is the first known asteroid to have been captured from another star system. The work is published in Monthly Notices of the Royal Astronomical Society: Letters.

The object known as 'Oumuamua was the last interstellar interloper to hit the headlines in 2017. However it was just a tourist passing through, whereas this former exo-asteroid - given the catchy name (514107) 2015 BZ509 - is a long-term resident.

All of the planets in our Solar System, and the vast majority of other objects as well, travel around the Sun in the same direction. However 2015 BZ509 is different - it moves in the opposite direction in what is known as a 'retrograde' orbit.

"How the asteroid came to move in this way while sharing Jupiter's orbit has until now been a mystery," explains Dr Fathi Namouni, lead author of the study. "If 2015 BZ509 were a native of our system, it should have had the same original direction as all of the other planets and asteroids, inherited from the cloud of gas and dust that formed them."

However the team ran simulations to trace the location of 2015 BZ509 right back to the birth of our Solar System, 4.5 billion years ago when the era of planet formation ended. These show that 2015 BZ509 has always moved in this way, and so could not have been there originally and must have been captured from another system.

[Continues . . .]
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Tank

If religions were TV channels atheism is turning the TV off.
"Religion is a culture of faith; science is a culture of doubt." ― Richard P. Feynman
'It is said that your life flashes before your eyes just before you die. That is true, it's called Life.' - Terry Pratchett
Remember, your inability to grasp science is not a valid argument against it.

Recusant

Current thinking based on observations is that 'Oumuamua is an interstellar comet or an alien space probe cunningly disguised as such;)

"`Oumuamua gets a boost" | ScienceDaily

Quote`Oumuamua -- the first interstellar object discovered within our Solar System -- has been the subject of intense scrutiny since its discovery in October 2017. Now, by combining data from the ESO's Very Large Telescope and other observatories, an international team of astronomers has found that the object is moving faster than predicted. The measured gain in speed is tiny and `Oumuamua is still slowing down because of the pull of the Sun -- just not as fast as predicted by celestial mechanics.

The team, led by Marco Micheli (European Space Agency) explored several scenarios to explain the faster-than-predicted speed of this peculiar interstellar visitor. The most likely explanation is that `Oumuamua is venting material from its surface due to solar heating -- a behaviour known as outgassing. The thrust from this ejected material is thought to provide the small but steady push that is sending `Oumuamua hurtling out of the Solar System faster than expected -- as of 1 June 2018 it is traveling at roughly 114,000 kilometres per hour.

Such outgassing is a behaviour typical for comets and contradicts the previous classification of `Oumuamua as an interstellar asteroid. "We think this is a tiny, weird comet," commented Marco Micheli. "We can see in the data that its boost is getting smaller the farther away it travels from the Sun, which is typical for comets."

Usually, when comets are warmed by the Sun they eject dust and gas, which form a cloud of material -- called a coma (cometary) -- around them, as well as the characteristic tail . However, the research team could not detect any visual evidence of outgassing.

"We did not see any dust, coma, or tail, which is unusual," explained co-author Karen Meech of the University of Hawaii, USA. Meech led the discovery team's characterisation of `Oumuamua in 2017. "We think that 'Oumuamua may vent unusually large, coarse dust grains."

[Continues . . .]
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Icarus


Recusant

Though the paper came out months ago, apparently it didn't get enough notice (to my shame I failed to catch it in the science news aggregators), so now one of the authors is doing interviews to get some publicity. "It really could have been a solar sail or even an alien probe. Really!" The main interview is in Haaretz, which has a strict paywall policy, so I've got a couple of other options.

"What is 'Oumuamua: Harvard Professor Avi Loeb defends his proposal it is an alien probe" | news.com.au

QuoteHarvard University Astronomy Department chair Avi Loeb is no stranger to controversy. His suggestion a strange object spotted entering our solar system from deep space could be an alien probe is just the most recent example.

Now, he's added fuel to the fire.

In an interview with the Israeli newspaper Haaretz, the Israeli professor has fiercely defended his hypothesis.

"As soon as we leave the solar system, I believe we will see a great deal of traffic out there," he said. "Possibly we'll get a message that says, 'Welcome to the interstellar club.' Or we'll discover multiple dead civilisations — that is, we'll find their remains."

At the heart of the debate is 'Oumuamua.

Translated from Hawaiian, it means "messenger sent from the distant past".

It came from outside the ecliptic — the flat swirl of planets, asteroids and stuff that was spun into place as our Solar System formed.

It was an odd reddish colour, suggesting extreme exposure to powerful cosmic rays.

It was relatively bright, at least compared with the average coal-black colour of most known comets and asteroids.

It was moving very, very fast. And it was seen to 'accelerate' as it moved away from the Sun as comets do. But it didn't have a comet's tail.

It was also seen to 'flicker' quickly, as though it was an elongated — or flat — object in a wild tumble.

'Oumuamua is certainly odd.

But, therefore aliens?

[Continues . . .]

"Thinking About Distant Civilizations Isn't Speculative" | Spiegel Online

QuoteDER SPIEGEL: Professor Loeb, do you have a favorite alien?

Loeb: To be honest, I don't like science fiction personally. I have a problem when the action in a movie violates the laws of physics. In those cases, I cannot enjoy the experience aesthetically.

DER SPIEGEL: If you don't like aliens, why are you exploring the question of intelligent extraterrestrial life?

Loeb: Because it's one of the really big questions. I have always been interested, even as a young kid, in thinking about the big picture. And the most fundamental of all questions is: Are we alone?

DER SPIEGEL: Why do you consider the question to be so fundamental?

Loeb: If at some point we encounter other intelligent beings, it would radically change our perspective of our importance in the big scheme of things. In addition, extraterrestrial intelligences could enormously increase our knowledge. Learning from them would improve our understanding of the world. It could be a shortcut -- just as if somebody from the Middle Ages were to get a glimpse of our world in the 21st century.

[Continues . . .]

"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Recusant

The latest hypothesis is that 'Oumuamua is a chunk of primordial hydrogen ice.

"Interstellar Oumuamua Was a Dark Hydrogen Iceberg" | Universe Today

QuoteWhen Canadian astronomer Robert Weryk discovered `Oumuamua passing through our Solar System with the Pan-STARRS telescope, in October 2017, it caused quite a stir. It was the first interstellar object we'd ever seen coming through our neighbourhood. The excitement led to speculation: what could it be?

There was lots of fun conjecture on its origins. Was it an alien spacecraft? A solar sail? Or something more prosaic?

As more observational evidence rolled in, ideas on `Oumuamua's nature followed. Was it a comet? It had no coma, so some thought it was a partially disintegrated comet, or an extrasolar comet. Could it be an asteroid? `Oumuamua was similar to asteroids in some respects, like its rotation rate. But it was an elongated cigar-shaped object, not round.

[various hypotheses described]

Now, a new study presents evidence suggesting a different origin for our first interstellar visitor: It's not a fragment of a much larger body, but a chunk of frozen hydrogen. A space iceberg.

[. . .]

The sublimation of the molecular hydrogen ice explains `Oumuamua's acceleration. In their paper, Seligman and Laughton explain that "H2 sublimation at a rate proportional to the incident solar flux generates a surface-covering jet that reproduces the observed acceleration."

The authors say that the molecular hydrogen ice also explains `Oumuamua's strange cigar shape, unusual for an object in space. They write "Mass wasting from sublimation leads to monotonic increase in the body axis ratio, explaining 'Oumuamua's shape."

[Continues . . .]

A draft version of the paper is available (PDF):

"Evidence that 1I/2017 U1 ('Oumuamua) was composed of molecular hydrogen ice." | Arxiv

QuoteAbstract:

'Oumuamua (I1 2017) was the first macroscopic (l ∼ 100 m) body observed to traverse the inner solar system on an unbound hyperbolic orbit. Its light curve displayed strong periodic variation, and it showed no hint of a coma or emission from molecular outgassing.

Astrometric measurements indicate that 'Oumuamua experienced non-gravitational acceleration on its outbound trajectory, but energy balance arguments indicate this acceleration is inconsistent with a water ice sublimation-driven jet of the type exhibited by solar system comets.

We show that all of 'Oumaumua's observed properties can be explained if it contained a significant fraction of molecular hydrogen (H2) ice. H2 sublimation at a rate proportional to the incident solar flux generates a surface-covering jet that reproduces the observed acceleration. Mass wasting from sublimation leads to monotonic increase in the body axis ratio, explaining 'Oumuamua's shape. Back-tracing 'Oumuamua's trajectory through the Solar System permits calculation of its mass and aspect ratio prior to encountering the Sun.

We show that H2-rich bodies plausibly form in the coldest dense cores of Giant Molecular Clouds, where number densities are of order n ∼ 105, and temperatures approach the T = 3 K background. Post-formation exposure to galactic cosmic rays implies a τ ∼ 100 Myr age, explaining the kinematics of 'Oumuamua's inbound trajectory.

[Paragraph breaks added. - R]



"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Ecurb Noselrub

For other ignoramuses like me, "sublimation" is when a solid goes to the gaseous phase without passing through the liquid phase, like ice cubes shrinking in the freezer. 

I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua. 

hermes2015

Quote from: Ecurb Noselrub on June 14, 2020, 02:08:14 AM
For other ignoramuses like me, "sublimation" is when a solid goes to the gaseous phase without passing through the liquid phase, like ice cubes shrinking in the freezer. 

I propose making a cigar named Oumuamua and smoking it in honor of Oumuamua.

Another example which is often given, but incorrectly, is iodine crystals. When heated, Iodine does in fact melt at 114°. One can boil the liquid iodine in a test tube to dry it, as I did many times when I needed anhydrous iodine. The boiling point is around 185°, when it refluxes on the inside walls of the test tube.
"Eventually everything connects - people, ideas, objects. The quality of the connections is the key to quality per se."
― Charles Eames