Search found 2479 matches
- Thu Jan 21, 2021 7:25 pm
- Forum: The Communications Center: Breaking Science News
- Topic: Tracing Gold's Cosmic Origin Story
- Replies: 9
- Views: 6559
Re: Tracing Gold's Cosmic Origin Story
Tracing Gold's Cosmic Origin Story Astronomers thought they had finally figured out where the gold, platinum, and other heavy elements in the universe came from. In light of recent results, they’re not so sure. by Ken Croswell Link: Proceedings of the National Academy of Sciences Thank you for this...
- Mon Nov 23, 2020 6:11 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Global Map: Mars at Opposition (2020 Nov 20)
- Replies: 24
- Views: 26921
Re: APOD: Global Map: Mars at Opposition (2020 Nov 20)
BDanielMayfield throws discredits about with gay abandon. Perhaps s/he would like to be more specific about where the discredits should fall, lest they fall back on her/im? Oh, I’m just being my somewhat contrarian and yet friendly self, a gentleman who dares to question everything, yet respectfull...
- Mon Nov 23, 2020 3:46 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Global Map: Mars at Opposition (2020 Nov 20)
- Replies: 24
- Views: 26921
Re: APOD: Global Map: Mars at Opposition (2020 Nov 20)
BDanielMayfield throws discredits about with gay abandon. Perhaps s/he would like to be more specific about where the discredits should fall, lest they fall back on her/im? Oh, I’m just being my somewhat contrarian and yet friendly self, a gentleman who dares to question everything, yet respectfull...
- Sun Nov 22, 2020 10:10 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
- Replies: 22
- Views: 11712
Re: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
In honor of all who mainly comment on what some object in an APOD looks like,
Perhaps it smells like a barnyard too. (All those aromatic hydrocarbons, etc.)
- Sun Nov 22, 2020 9:56 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
- Replies: 22
- Views: 11712
Re: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
Stellar density in solar neighborhood is only 0.004 stars per cubic light year :!: Stellar density is the average number of stars within a unit volume. It is similar to the stellar mass density, which is the total solar masses (MSun) found within a unit volume. Typically, the volume used by astrono...
- Sun Nov 22, 2020 9:39 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Global Map: Mars at Opposition (2020 Nov 20)
- Replies: 24
- Views: 26921
Re: APOD: Global Map: Mars at Opposition (2020 Nov 20)
I wholeheartedly endorse this discredation. (My brain also concurs.)neufer wrote: ↑Sun Nov 22, 2020 4:45 pmBDanielMayfield wrote: ↑Sat Nov 21, 2020 4:21 pm
A lot of theories still need to be formally discredited.
- I hereby discredit them all
- Sun Nov 22, 2020 1:33 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
- Replies: 22
- Views: 11712
Re: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
Stellar density in solar neighborhood is only 0.004 stars per cubic light year :!: Stellar density is the average number of stars within a unit volume. It is similar to the stellar mass density, which is the total solar masses (MSun) found within a unit volume. Typically, the volume used by astronom...
- Sun Nov 22, 2020 1:04 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
- Replies: 22
- Views: 11712
Re: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
500 light year away in that direction and there are no stars in front of it? That seems unlikely. But this cloud is very small as these objects go, being "only half a light year across." Something that small even at that distance could easily have no stars between us and it. Space is most...
- Sun Nov 22, 2020 12:54 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
- Replies: 22
- Views: 11712
Re: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
500 light year away in that direction and there are no stars in front of it? That seems unlikely. But this cloud is very small as these objects go, being "only half a light year across." Something that small even at that distance could easily have no stars between us and it. Space is most...
- Sun Nov 22, 2020 12:39 pm
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Quanta: Big Bounce Simulations Challenge the Big Bang
- Replies: 9
- Views: 6788
Re: Quanta: Big Bounce Simulations Challenge the Big Bang
The intellectual waters are deeper than we are tall here, but still we try to tread along. I could certainly be wrong, but Ann, you might be conflating two different things here: Universal shape and universal destiny, space and time. The universe's shape can be closed, flat or open while it's destin...
- Sun Nov 22, 2020 6:09 am
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Quanta: Big Bounce Simulations Challenge the Big Bang
- Replies: 9
- Views: 6788
Re: Quanta: Big Bounce Simulations Challenge the Big Bang
It is correct, that Dark matter has 10 different types? And you have to use it in your mathematical models. Or I forgot something? 1. Very small neutron stars, young pulsars, quark stars. 2. Black holes and jets from electrons. 3. Red dwarfes (the smallest and coolest kind of star), any planets. 4....
- Sun Nov 22, 2020 5:57 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
- Replies: 22
- Views: 11712
Re: APOD: Dark Molecular Cloud Barnard 68 (2020 Nov 22)
... half a light-year across. It is not known exactly how molecular clouds like Barnard 68 form, but it is known that these clouds are themselves likely places for new stars to form. In fact, Barnard 68 itself has been found likely to collapse and form a new star system. This then is proof that not...
- Sat Nov 21, 2020 4:21 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Global Map: Mars at Opposition (2020 Nov 20)
- Replies: 24
- Views: 26921
Re: APOD: Global Map: Mars at Opposition (2020 Nov 20)
A lot of theories still need to be formally discredited.
- Fri Nov 20, 2020 5:01 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Global Map: Mars at Opposition (2020 Nov 20)
- Replies: 24
- Views: 26921
Re: APOD: Global Map: Mars at Opposition (2020 Nov 20)
But since Meridiani Planum is not really well defined, it looks like some other convention was agreed upon as the exact location of the Martian prime meridian. Looking at this map from http://planetary-science.org/wp-content/uploads/2014/12/GhoO4SV.jpg, I see one small crater in particular that see...
- Wed Nov 18, 2020 6:12 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: A Double Star Cluster in Perseus (2020 Nov 18)
- Replies: 15
- Views: 7361
Re: APOD: A Double Star Cluster in Perseus (2020 Nov 18)
https://apod.nasa.gov/apod/calendar/S_201118.jpg A Double Star Cluster in Perseus Explanation: Most star clusters are singularly impressive. Open clusters NGC 869 and NGC 884, however, could be considered doubly impressive. Also known as "h and chi Persei", this unusual double cluster , s...
- Wed Nov 18, 2020 2:15 pm
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: A Double Star Cluster in Perseus (2020 Nov 18)
- Replies: 15
- Views: 7361
Re: APOD: A Double Star Cluster in Perseus (2020 Nov 18)
One night decades ago I came across the Double Cluster by accident while randomly scanning the sky with a pair of new binoculars. It was quite impressive!
- Tue Nov 17, 2020 3:55 pm
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Heaviest Element In Stellar Spectra
- Replies: 7
- Views: 6407
Re: Heaviest Element In Stellar Spectra
So uranium, Z=92, half life of most stable isotope U-238 at 4.468×10^9 years, is the heaviest element found in a main sequence star's spectra. But what about kilo or supernova stellar remnants? Is there evidence for any of the trans-uranium elements in stellar explosions?
- Mon Nov 16, 2020 8:46 pm
- Forum: The Communications Center: Breaking Science News
- Topic: HEAPOW: Old Star Blowing Bubbles (2020 Nov 16)
- Replies: 3
- Views: 3728
Re: HEAPOW: Old Star Blowing Bubbles (2020 Nov 16)
https://upload.wikimedia.org/wikipedia/commons/7/77/Druse.jpg <<Amethyst is a purple variety of quartz (SiO2) and owes its violet color to irradiation, impurities of iron and in some cases other transition metals, and the presence of other trace elements, which result in complex crystal lattice sub...
- Mon Nov 16, 2020 7:03 pm
- Forum: Open Space: Discuss Anything
- Topic: Weather!
- Replies: 2869
- Views: 1140620
Re: Weather!
More on the above comment from weather.com: Hurricane Iota is nearing Central America as a dangerous Category 5, where it will bring potentially catastrophic rainfall flooding, mudslides, storm surge and damaging winds for the second time in two weeks. Late Monday morning, Iota became only the secon...
- Mon Nov 16, 2020 5:18 pm
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Heaviest Element In Stellar Spectra
- Replies: 7
- Views: 6407
Re: Heaviest Element In Stellar Spectra
I[t] appears that every stable element has been detected in stars, at least up to uranium. This shows the spectroscopically determined abundances of elements from copper to uranium in Sirius A (the black stars) and in the Sun (the blue Sun symbols). Reference. Update: actually, I note that the grap...
- Mon Nov 16, 2020 5:07 pm
- Forum: Open Space: Discuss Anything
- Topic: Weather!
- Replies: 2869
- Views: 1140620
Re: Weather!
Unlike the meaning "the slightest amount" hurricane Iota has now exceeded forecasts, becoming a CAT 5 hurricane! This makes it the strongest hurricane of this horrible 2020 Atlantic hurricane season.
- Mon Nov 16, 2020 12:22 pm
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Heaviest Element In Stellar Spectra
- Replies: 7
- Views: 6407
Re: Heaviest Element In Stellar Spectra
Pb (lead, element 82) might be tough to beat Art. What prompted my question was this: Abstract The thermal evolution of rocky planets on geological timescales (Gyr) depends on the heat input from the long-lived radiogenic elements potassium, thorium, and uranium. Concentrations of the latter two in ...
- Sat Nov 14, 2020 5:16 am
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: Heaviest Element In Stellar Spectra
- Replies: 7
- Views: 6407
Heaviest Element In Stellar Spectra
What is the heaviest element as yet detected in any star’s spectrum?
- Thu Nov 12, 2020 5:24 am
- Forum: Open Space: Discuss Anything
- Topic: Covid-19
- Replies: 57
- Views: 33319
Re: Covid-19
This disease does not appear to confer any lasting immunity on those who get it. So our hope for herd immunity hangs on the right kind of vaccine. Otherwise, we'd better develop effective treatments. That's not at all reassuring. If catching this damn contagion doesn't even confer lasting immunity,...
- Thu Nov 12, 2020 2:47 am
- Forum: Open Space: Discuss Anything
- Topic: Covid-19
- Replies: 57
- Views: 33319
Re: Covid-19
This disease does not appear to confer any lasting immunity on those who get it. So our hope for herd immunity hangs on the right kind of vaccine. Otherwise, we'd better develop effective treatments. That's not at all reassuring. If catching this damn contagion doesn't even confer lasting immunity,...