by neufer » Fri Aug 07, 2015 8:05 pm
Chris Peterson wrote:puhbrox wrote:
What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?
I'm skeptical that this supernova appeared to the ancient Greeks (in ~500 BCE as suggested by the graphic). The paper dates the formation of the x-ray system to as much as 4600 years ago, which means 2500 BCE. The Greeks were still isolated tribes. This was the period of the Egyptian Old Kingdom, of Mesopotamia and the rise of Ur, of the Indus Valley civilization.
A supernova like this would appear as a very bright star in the sky, likely visible in the day for a few weeks or months. Probably very scary to cultures that tended to look on any unexpected events in the sky as harbingers of doom.
Egyptologists believe that the Great Pyramid of Giza was built as a tomb over a 10 to 20-year period concluding around 2560 BCE.
- But the first recorded supernova was by Chinese astronomers 1830 years ago
[also in Circinus but much closer: 9,100 ly vs. 30,700 ly for Circinus X-1
(; i.e., apparent magnitude -1.4 vs. -4)]:
https://en.wikipedia.org/wiki/SN_185 wrote:
<<SN 185 (aka RCW 86) was a supernova which appeared in the year AD 185, near the direction of Alpha Centauri, between the constellations Circinus and Centaurus, centered at RA 14h 43m Dec −62° 30′, in Circinus. This "guest star" was observed by Chinese astronomers in the Book of Later Han, and might have been recorded in Roman literature. It remained visible in the night sky for eight months. This is believed to have been the first supernova recorded.
The gaseous shell RCW 86 is probably the supernova remnant of this event and has a relatively large angular size of roughly 45 arc minutes (larger than the apparent size of the full moon, which varies from 29 to 34 arc minutes). The distance to RCW 86 is estimated to be 2,800 parsecs (9,100 light-years). Recent X-ray studies show a good match for the expected age.
Differing modern interpretations of the Chinese records of the guest star have led to quite different suggestions for the astronomical mechanism behind the event, from a core-collapse supernova to a distant, slow-moving comet – with correspondingly wide-ranging estimates of its apparent visual magnitude (−8 to +4). The recent Chandra results suggest that it was most likely a Type Ia supernova (a type with consistent absolute magnitude), similar therefore to Tycho's star (which had apparent magnitude −4 at a similar distance).>>
[quote="Chris Peterson"][quote="puhbrox"]
What exactly did this look like to the Ancient Greeks? Was it something EXTREMELY bright in the plane of the milky way? On the same note, did we just stumble across these ripples and strange cloud formations, or do a lot of neutron stars look like this and we are finally only able to see this strange array now thanks to Chandra?[/quote]
I'm skeptical that this supernova appeared to the ancient Greeks (in ~500 BCE as suggested by the graphic). The paper dates the formation of the x-ray system to as much as 4600 years ago, which means 2500 BCE. The Greeks were still isolated tribes. This was the period of the Egyptian Old Kingdom, of Mesopotamia and the rise of Ur, of the Indus Valley civilization.
A supernova like this would appear as a very bright star in the sky, likely visible in the day for a few weeks or months. Probably very scary to cultures that tended to look on any unexpected events in the sky as harbingers of doom.[/quote]
Egyptologists believe that the Great Pyramid of Giza was built as a tomb over a 10 to 20-year period concluding around 2560 BCE.
[list]But the first [b][u]recorded[/u][/b] supernova was by Chinese astronomers 1830 years ago
[also in Circinus but [b][u]much closer[/u][/b]: 9,100 ly vs. 30,700 ly for Circinus X-1
(; i.e., apparent magnitude -1.4 vs. -4)]:[/list]
[quote=" https://en.wikipedia.org/wiki/SN_185"]
[float=right][img3="[b][size=150][color=#0000FF]SN 185 (aka RCW 86)[/color][/size][/b]"]https://upload.wikimedia.org/wikipedia/commons/9/98/Rcw86_420.jpg[/img3][/float]<<SN 185 (aka RCW 86) was a supernova which appeared in the year AD 185, near the direction of Alpha Centauri, between the constellations Circinus and Centaurus, centered at RA 14h 43m Dec −62° 30′, in Circinus. This "guest star" was observed by Chinese astronomers in the Book of Later Han, and might have been recorded in Roman literature. It remained visible in the night sky for eight months. This is believed to have been the first supernova recorded.
The gaseous shell RCW 86 is probably the supernova remnant of this event and has a relatively large angular size of roughly 45 arc minutes (larger than the apparent size of the full moon, which varies from 29 to 34 arc minutes). The distance to RCW 86 is estimated to be 2,800 parsecs (9,100 light-years). Recent X-ray studies show a good match for the expected age.
Differing modern interpretations of the Chinese records of the guest star have led to quite different suggestions for the astronomical mechanism behind the event, from a core-collapse supernova to a distant, slow-moving comet – with correspondingly wide-ranging estimates of its apparent visual magnitude (−8 to +4). The recent Chandra results suggest that it was most likely a Type Ia supernova (a type with consistent absolute magnitude), similar therefore to Tycho's star (which had apparent magnitude −4 at a similar distance).>>[/quote]