Author Topic: Astronomy & Planetary Science Thread  (Read 441989 times)

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #600 on: 11/25/2018 09:00 am »
VVV-WIT-07: another Boyajian's star or a Mamajek's object?

Quote
We report the discovery of VVV-WIT-07, an unique and intriguing variable source presenting a sequence of recurrent dips with a likely deep eclipse in July 2012. The object was found serendipitously in the near-IR data obtained by the VISTA Variables in the Vía Láctea (VVV) ESO Public Survey. Our analysis is based on VVV variability, multicolor, and proper motion (PM) data. Complementary data from the VVV eXtended survey (VVVX) as well as archive data and spectroscopic follow-up observations aided in the analysis and interpretation of VVV-WIT-07. A search for periodicity in the VVV Ks-band light curve of VVV-WIT-07 results in two tentative periods at P~322 days and P~170 days. Colors and PM are consistent either with a reddened MS star or a pre-MS star in the foreground disk. The near-IR spectra of VVV-WIT-07 appear featureless, having no prominent lines in emission or absorption. Features found in the light curve of VVV-WIT-07 are similar to those seen in J1407 (Mamajek's object), a pre-MS K5 dwarf with a ring system eclipsing the star or, alternatively, to KIC 8462852 (Boyajian's star), an F3 IV/V star showing irregular and aperiodic dips in its light curve. Alternative scenarios, none of which is fully consistent with the available data, are also briefly discussed, including a young stellar object, a T Tauri star surrounded by clumpy dust structure, a main sequence star eclipsed by a nearby extended object, a self-eclipsing R CrB variable star, and even a long-period, high-inclination X-ray binary.

https://arxiv.org/abs/1811.02265

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Astronomy Thread
« Reply #601 on: 11/29/2018 08:30 pm »
Prehistoric cave art reveals ancient use of complex astronomy

Quote
Some of the world's oldest cave paintings have revealed how ancient people had relatively advanced knowledge of astronomy.

The artworks, at sites across Europe, are not simply depictions of wild animals, as was previously thought. Instead, the animal symbols represent star constellations in the night sky, and are used to represent dates and mark events such as comet strikes, analysis suggests.

They reveal that, perhaps as far back as 40,000 years ago, humans kept track of time using knowledge of how the position of the stars slowly changes over thousands of years.

The findings suggest that ancient people understood an effect caused by the gradual shift of Earth's rotational axis. Discovery of this phenomenon, called precession of the equinoxes, was previously credited to the ancient Greeks.

Quote
Dr Martin Sweatman, of the University of Edinburgh's School of Engineering, who led the study, said: "Early cave art shows that people had advanced knowledge of the night sky within the last ice age. Intellectually, they were hardly any different to us today.

"These findings support a theory of multiple comet impacts over the course of human development, and will probably revolutionise how prehistoric populations are seen."

What happens when materials take tiny hits

Quote
When tiny particles strike a metal surface at high speed — for example, as coatings being sprayed or as micrometeorites pummeling a space station — the moment of impact happens so fast that the details of process haven’t been clearly understood, until now.
A team of researchers at MIT has just accomplished the first detailed high-speed imaging and analysis of the microparticle impact process, and used that data to predict when the particles will bounce away, stick, or knock material off the surface and weaken it. The new findings are described in a paper appearing today in the journal Nature Communications.
« Last Edit: 11/29/2018 08:42 pm by Star One »

Offline leovinus

  • Full Member
  • ****
  • Posts: 1095
  • Porto, Portugal
  • Liked: 867
  • Likes Given: 1727
Re: Astronomy Thread
« Reply #602 on: 11/29/2018 08:47 pm »
StarOne, just so you know, this thread and your efforts are very much appreciated! For Astronomy, I follow this daily, as well as Astro Blogs.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #603 on: 11/29/2018 08:51 pm »
StarOne, just so you know, this thread and your efforts are very much appreciated! For Astronomy, I follow this daily, as well as Astro Blogs.

Thank you. I know that MIT press release above isn’t really astronomy but I couldn’t think where else to put it and it’s not worth its own thread.

Offline as58

  • Full Member
  • ****
  • Posts: 835
  • Liked: 300
  • Likes Given: 186
Re: Astronomy Thread
« Reply #604 on: 11/29/2018 09:16 pm »
Prehistoric cave art reveals ancient use of complex astronomy

Quote
Some of the world's oldest cave paintings have revealed how ancient people had relatively advanced knowledge of astronomy.

The artworks, at sites across Europe, are not simply depictions of wild animals, as was previously thought. Instead, the animal symbols represent star constellations in the night sky, and are used to represent dates and mark events such as comet strikes, analysis suggests.

They reveal that, perhaps as far back as 40,000 years ago, humans kept track of time using knowledge of how the position of the stars slowly changes over thousands of years.

The findings suggest that ancient people understood an effect caused by the gradual shift of Earth's rotational axis. Discovery of this phenomenon, called precession of the equinoxes, was previously credited to the ancient Greeks.

Quote
Dr Martin Sweatman, of the University of Edinburgh's School of Engineering, who led the study, said: "Early cave art shows that people had advanced knowledge of the night sky within the last ice age. Intellectually, they were hardly any different to us today.

"These findings support a theory of multiple comet impacts over the course of human development, and will probably revolutionise how prehistoric populations are seen."

I haven't read the actual article, but the press release doesn't sound very credible.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Astronomy Thread
« Reply #605 on: 12/01/2018 08:40 am »
Astronomers Are Tracking Four Potential Interstellar Objects Now In Our Outer Solar System

Quote
Using detailed computer models of asteroidal-type objects between the Sun and Jupiter, two Harvard University researchers find that at least four known objects are likely to have origins from outside our solar system.
« Last Edit: 12/01/2018 08:40 am by Star One »

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #606 on: 12/04/2018 07:46 am »
Combination of Space-based and Ground-based Telescopes Reveals more than 100 Exoplanets

Quote
An international research team involving researchers at the University of Tokyo and Astrobiology Center of the National Institutes of Natural Sciences investigated 227 K2 exoplanet candidates using other space telescopes and ground-based telescopes. They confirmed that 104 of them are really exoplanets. Seven of the confirmed exoplanets have ultra-short orbital periods less than 24 hours. The formation process of exoplanets with such short orbital periods is still unclear. Further study of these ultra-short period planets will help to advance research into the processes behind their formation. They also confirmed many low-mass rocky exoplanets with masses less than twice that of the Earth as well as some planetary systems with multiple exoplanets.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #607 on: 12/07/2018 06:51 am »
Ganymede, Jupiter’s largest moon, shows signs of past tectonic activity

Quote
Galileo spacecraft data suggests fault lines that shear against one another horizontally, like the San Andreas fault found in California.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #608 on: 12/08/2018 09:59 am »
Enormous ‘ghost’ galaxy spotted hiding next to the Milky Way

Quote
A galaxy a third the size of our own, but extremely faint, has been observed orbiting around the Milky Way.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #609 on: 12/11/2018 10:55 pm »
http://news.ku.edu/2018/12/05/researchers-consider-whether-supernovae-killed-large-ocean-animals-dawn-pleistocene

Quote
About 2.6 million years ago, an oddly bright light arrived in the prehistoric sky and lingered there for weeks or months. It was a supernova some 150 light years away from Earth. Within a few hundred years, long after the strange light in the sky had dwindled, a tsunami of cosmic energy from that same shattering star explosion could have reached our planet and pummeled the atmosphere, touching off climate change and triggering mass extinctions of large ocean animals, including a shark species that was the size of a school bus.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #610 on: 12/12/2018 07:03 pm »
A batch of new videos from ESO.
















Offline whitelancer64

Re: Astronomy Thread
« Reply #611 on: 12/12/2018 07:48 pm »
Prehistoric cave art reveals ancient use of complex astronomy

Quote
Some of the world's oldest cave paintings have revealed how ancient people had relatively advanced knowledge of astronomy.

The artworks, at sites across Europe, are not simply depictions of wild animals, as was previously thought. Instead, the animal symbols represent star constellations in the night sky, and are used to represent dates and mark events such as comet strikes, analysis suggests.

They reveal that, perhaps as far back as 40,000 years ago, humans kept track of time using knowledge of how the position of the stars slowly changes over thousands of years.

The findings suggest that ancient people understood an effect caused by the gradual shift of Earth's rotational axis. Discovery of this phenomenon, called precession of the equinoxes, was previously credited to the ancient Greeks.

Quote
Dr Martin Sweatman, of the University of Edinburgh's School of Engineering, who led the study, said: "Early cave art shows that people had advanced knowledge of the night sky within the last ice age. Intellectually, they were hardly any different to us today.

"These findings support a theory of multiple comet impacts over the course of human development, and will probably revolutionise how prehistoric populations are seen."

I haven't read the actual article, but the press release doesn't sound very credible.

There's an article with some more detail here:

https://www.universetoday.com/140705/prehistoric-cave-paintings-show-that-ancient-people-had-pretty-advanced-knowledge-of-astronomy/

Apparently, comparing cave paintings and other artwork at several sites indicates some correspond to the constellations as they appeared at the time. That could just be a coincidence, but the dates of the artwork also seem to correspond to known cometary impacts. They conclude the two may be linked, that the art is something like a memorial to major astronomical events.

The general concept that some cave paintings may represent constellations is not a new one.

http://journalofcosmology.com/Consciousness159.html

Some of the evidence is quite strong: one painting of a bull in Lascaux Cave has six dots over one shoulder, to represent the Pleiades, as well as two dots in its head, that may represent stars in the constellation Taurus.

The new paper seems to be presenting the idea that other constellations were also accurately represented and also that they may represent major astronomical events. Fair enough, may be, but I'm less convinced of their idea that this means the prehistoric peoples understood the precession of the equinoxes.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline as58

  • Full Member
  • ****
  • Posts: 835
  • Liked: 300
  • Likes Given: 186
Re: Astronomy Thread
« Reply #612 on: 12/13/2018 10:04 am »
Apparently, comparing cave paintings and other artwork at several sites indicates some correspond to the constellations as they appeared at the time. That could just be a coincidence, but the dates of the artwork also seem to correspond to known cometary impacts. They conclude the two may be linked, that the art is something
like a memorial to major astronomical events.

The existence of those relatively recent cometary impacts is very much in dispute in the first place. Also, the interpretation of cave paintings as asterisms (which somehow seem to follow closely the modern constellations) seems stretched; the figures in Appendix B aren't convincing.

Not that academic expertise necessarily means anything, but neither of the authors seems to be an astronomer or archaeologist.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #613 on: 12/14/2018 12:16 pm »
Video from Cool Worlds about RNAAS banned on ArXiv


Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #614 on: 12/16/2018 02:27 pm »
Fireball That Exploded Over Greenland Shook Earth, Triggering Seismic Sensors

Quote
When a blazing fireball from space exploded over Earth on July 25, scientists captured the first-ever seismic recordings of a meteor impact on ice in Greenland.

At approximately 8 p.m. local time on that day, residents of the town of Qaanaaq on Greenland's northwestern coast reported seeing a bright light in the sky and feeling the ground shake as a meteor combusted over the nearby Thule Air Base.

But the fleeting event was detected by more than just human observers, according to unpublished research presented Dec. 12 here at the annual conference of the American Geophysical Union (AGU).

Offline SciNews

  • Full Member
  • ****
  • Posts: 812
  • Romania
  • Liked: 737
  • Likes Given: 6
Re: Astronomy Thread
« Reply #615 on: 12/17/2018 05:23 pm »
2018 VG18 “Farout” the most distant body observed in the Solar System

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #616 on: 12/17/2018 08:18 pm »
Here’s the press release from the Carnegie.

DISCOVERY OF THE MOST DISTANT SOLAR SYSTEM OBJECT EVER OBSERVED

Quote
A team of astronomers has discovered the most-distant body ever observed in our Solar System.  It is the first known Solar System object that has been detected at a distance that is more than 100 times farther than Earth is from the Sun.
 
The new object was announced on Monday, December 17, 2018 by the International Astronomical Union’s Minor Planet Center and has been given the provisional designation 2018 VG18. The discovery was made by Carnegie’s Scott S. Sheppard, the University of Hawaii’s David Tholen, and Northern Arizona University’s Chad Trujillo.
 
2018 VG18, nicknamed “Farout” by the discovery team for its extremely distant location, is at about 120 astronomical units (AU), where 1 AU is defined as the distance between the Earth and Sun.  The second-most-distant observed Solar System object is Eris, at about 96 AU.  Pluto is currently at about 34 AU, making 2018 VG18 more than three-and-a-half times more distant than the Solar System’s most-famous dwarf planet.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Re: Astronomy Thread
« Reply #617 on: 12/17/2018 09:08 pm »
Alien Imposters: Planets with Oxygen Don’t Necessarily Have Life

In their search for life in solar systems near and far, researchers have often accepted the presence of oxygen in a planet’s atmosphere as the surest sign that life may be present there. A new Johns Hopkins study, however, recommends a reconsideration of that rule of thumb.
Simulating in the lab the atmospheres of planets beyond the solar system, researchers successfully created both organic compounds and oxygen, absent of life.
The findings, published on Dec. 11, 2018, in ACS Earth and Space Chemistry, serve as a cautionary tale for researchers who suggest the presence of oxygen and organics on distant worlds is evidence of life there.
Oxygen makes up 20 percent of Earth’s atmosphere and is considered one of the most robust biosignature gases in Earth’s atmosphere. In the search for life beyond Earth’s solar system, however, little is known about how different energy sources initiate chemical reactions and how those reactions can create biosignatures like oxygen. While other researchers have run photochemical models on computers to predict what exoplanet atmospheres might be able to create, no such simulations to He’s knowledge have before now been conducted in the lab.

Chao He explaining how the study’s PHAZER setup works.
Credit: Chanapa Tantibanchachai
The research team performed the simulation experiments in a specially designed Planetary HAZE (PHAZER) chamber in the lab of Sarah Hörst, assistant professor of Earth and planetary sciences and the paper’s co-author. The researchers tested nine different gas mixtures, consistent with predictions for super-Earth and mini-Neptune type exoplanet atmospheres; such exoplanets are the most abundant type of planet in our Milky Way galaxy. Each mixture had a specific composition of gases such as carbon dioxide, water, ammonia, and methane, and each was heated at temperatures ranging from about 80 to 700 degrees Fahrenheit.
He and the team allowed each gas mixture to flow into the PHAZER setup and then exposed the mixture to one of two types of energy, meant to mimic energy that triggers chemical reactions in planetary atmospheres: plasma from an alternating current glow discharge or light from an ultraviolet lamp. Plasma, an energy source stronger than UV light, can simulate electrical activities like lightning and/or energetic particles, and UV light is the main driver of chemical reactions in planetary atmospheres such as those on Earth, Saturn and Pluto.
After running the experiments continuously for three days, corresponding to the amount of time gas would be exposed to energy sources in space, the researchers measured and identified resulting gasses with a mass spectrometer, an instrument that sorts chemical substances by their mass to charge ratio.

A CO2-rich planetary atmosphere exposed to a plasma discharge in Sarah Hörst’s lab.
Credit: Chao He
The research team found multiple scenarios that produced both oxygen and organic molecules that could build sugars and amino acids—raw materials for which life could begin—such as formaldehyde and hydrogen cyanide.
“People used to suggest that oxygen and organics being present together indicates life, but we produced them abiotically in multiple simulations,” He says. “This suggests that even the co-presence of commonly accepted biosignatures could be a false positive for life.”
This study was funded by the NASA Exoplanets Research Program Grant NNX16AB45G. Chao He received funding from the Morton K. and Jane Blaustein Foundation.
###
Johns Hopkins University news releases are available online, as is information for reporters. To arrange a video or audio interview with a Johns Hopkins expert, contact a media representative listed above or visit our studio web page. Find more Johns Hopkins stories on the Hub.

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Astronomy Thread
« Reply #618 on: 12/21/2018 08:52 pm »
NASA and the Search for Technosignatures: A Report from the NASA Technosignatures Workshop

NASA Technosignatures Workshop Participants
(Submitted on 20 Dec 2018)
This report is the product of the NASA Technosignatures Workshop held at the Lunar and Planetary Institute in Houston, Texas, in September 2018. This workshop was convened by NASA for the organization to learn more about the current field and state of the art of searches for technosignatures, and what role NASA might play in these searches in the future. The report, written by the workshop participants, summarizes the material presented at the workshop and incorporates additional inputs from the participants. Section 1 explains the scope and purpose of the document, provides general background about the search for technosignatures, and gives context for the rest of the report. Section 2 discusses which experiments have occurred, along with current limits on technosignatures. Section 3 addresses the current state of the technosignature field as well as the state-of-the-art for technosignature detection. Section 4 addresses near-term searches for technosignatures, and Section 5 discusses emerging and future opportunities in technosignature detection.

https://arxiv.org/abs/1812.08681

Intermediate Mass Black Holes Discovered in Galactic Nuclei
Friday, December 21, 2018
Science Update - A look at CfA discoveries from recent journals
The existence of black holes is well established, and observations have found both stellar mass sized objects and giant ones millions to billions times more massive than the sun at the centers of galaxies. But the origin of these massive black holes is a mystery. Small black holes are the ashes of supernovae, but massive ones presumably must start small and grow over time. Such growth is highly constrained, however, because the vary act of accreting material generates radiation that inhibits further inflow, and billions of years are thought to be needed to make billion solar-mass black holes. The problem arises because astronomers have now detected quasars with supermassive black holes in the early universe - but there has not been enough time since the big bang for them to grow to supermassive sizes. Stellar mass black holes, furthermore, should have produced many intermediate mass black holes as they grew, yet only a few are candidates and their identification as IMBHs remains controversial. The firm identification of IMBHs could help clarify the issue. An alternative suggestion has been advanced to solve the problem. The direct collapse of a large gas cloud in the early universe could produce an intermediate-sized black hole (IMBH) with hundreds to hundreds of thousands of solar masses, leaving plenty of time for them all to grow by now into supermassive objects.

CfA astronomer Igor Chilingarian led a team that has for the first time identified a set of galaxies with active nuclei hosting intermediate mass black holes. They used optical and near-infrared galaxy surveys to identify candidate sources from the intensity and velocities of their atomic emission lines, selecting three hundred and five likely IMBH candidates. They then obtained X-ray measurements from the Chandra and/or XMM missions which confirmed that ten of these nuclei were IMBHs and were actively accreting. The least massive IMBH they discovered in their set of ten had thirty-six thousand solar-masses; the largest had about ten times more. Their discovery is remarkable not only because it marks the first conclusive detection of these elusive objects, but because it lends credence to the idea that stellar-mass black holes seeded the early universe, with many of them then growing into the supermassive monsters we see today.

Reference(s):
"A Population of Bona Fide Intermediate-mass Black Holes Identified as Low-luminosity Active Galactic Nuclei," Igor V. Chilingarian, Ivan Yu. Katkov, Ivan Yu. Zolotukhin, Kirill A. Grishin, Yuri Beletsky, Konstantina Boutsia, and David J. Osip, ApJ 863, 1 2018.
« Last Edit: 12/21/2018 08:55 pm by Star One »

Offline Star One

  • Senior Member
  • *****
  • Posts: 13997
  • UK
  • Liked: 3974
  • Likes Given: 220
Astronomy Thread
« Reply #619 on: 12/22/2018 09:38 am »
Stephen Hawking's Final Theory About Our Universe Will Melt Your Brain

Quote
The paper, published in the Journal of High Energy Physics in May, puts forward that the Universe is far less complex than current multiverse theories suggest.

It's based around a concept called eternal inflation, first introduced in 1979 and published in 1981.
« Last Edit: 12/22/2018 09:39 am by Star One »

 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0