Whole thing wreaks of Cloak and Daggery to me:
https://www.bbc.co.uk/news/world-europe-66562629
Best regards from our man in Portsmouth, UK.
https://www.bbc.co.uk/news/world-europe-66562629
Best regards from our man in Portsmouth, UK.
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I assume data is calculated on red shift as parallax can only work out to ~360 light years and probably isn't that good at that distance. The database is larger now and probability has shifted from 5 sigma to 3. Big difference ~1 in 100 event "error" compared with 1 in several million events. All that is being said is that serious discoveries need to be correct to 5 sigma.
😉 Maybe an odd way of putting it but data needs to fit into these limits. 1 in 100 error in the data isn't that bad really. As these things "aren't there" and then get so bright they can be detected they are a very convenient thing to use. 😉 And seem to be consistent over 11 billion years. That appears to be the most distant discoveries.
Supernovae in general are a diverse group with a large range of peak brightnesses.
It was only when supernovae were subdivided into subgroups that the consistency of T1a supernovae came to light (no pun intended!).
The spectra of T1a supernovae match feature by feature, as do their light curves (the plots of waxing and waning brightness in the weeks following a supernova explosion).
Examination of many individual spectral and light curve fingerprints allowed astronomers to recognise those T1a supernovae that had the same peak brightness, thus identifying which ones to use as standard candles.
The main problem with T1a supernovae is that a defence of them has to be prepared against skeptics!
I think we've established that nothing is solid in this field!
Account has to be taken of the filters we use since T1a supernovae peak in the blue-violet end of the spectrum in their own rest frame, but we observe them with a red-infrared filter because the blue-violet is redshifted.
Account also has to be taken of the effect of dust in the T1a supernova's host galaxy.
Account has to be taken of the filters we use since T1a supernovae peak in the blue-violet end of the spectrum in their own rest frame, but we observe them with a red-infrared filter because the blue-violet is redshifted.
Account also has to be taken of the effect of dust in the T1a supernova's host galaxy.
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Here's more information on standard candles. I hope it proves illuminating! 😀
There is a limit, called the Chandrashekar limit, to how massive a white dwarf can become by drawing matter from its stellar companion.
Beyond that limit, which is 1.4 solar masses, the white dwarf beomes unstable and goes supernova.
Apparently, by looking at the mass-luminosity relation for stellar evolution, the intrinsic luminosity of T1a supernovae can be determined from the Chandrashekar limit.
However, several T1a supernovae have now been observed that are very bright, and thought to have originated from white dwarfs whose masses exceeded the Chandrasekhar limit.
Scientists point out that such observations pose a challenge to the use of type Ia supernovae as standard candles.
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Yet another video that is primarily produced to make money.
😉Another source but tends to be more intellectual than some others - at times.
https://www.nationalgeographic.com/science/article/type-1a-supernovas-cosmic-candle-mystery
The shear number of "news" / "opinion" sources these days is a bit of a problem. All want to grab people's attention.
Unfortunately, I am being asked to create an account to unlock that story.
Some type 1a supernovae are intrinsically brighter than others, but these flare and fade more slowly, and a correlation between the brightness and the width of the light curve allows astronomers to apply a correction to standardise their observations.
The reason T1a supernovae are not all the same brightnes is thought to be due to an asymmetry in their explosions which makes them look different at different angles.
Another reason could be the differences in the chemical compositions of stars at different times in the history of the universe.
https://www.universetoday.com/37333...ae-has-implications-for-studying-dark-energy/
I was too so ignored and read. Think they allow a few reads and then months before that can be done again. 😉 It's not that intellectual but better than some.
I'm in a bad mood. Went to some trouble to get a win10 laptop. 🙁 I do not want a free upgrade to 11. Not keen on their apparent reasons for wanting people to update.
Silly me, I am able to click off the create an account window!
Here are two salient quotes from the National Geographic article:
- "Despite their crucial cosmological importance, type 1a supernovae are still very much a mystery. As astronomers study more and more of them, it’s becoming increasingly clear just how non-standard these explosions actually are – and how little we really know about them."
- “They’re standardizable candles, not standard candles."
P.S. I got my Windows 8.1 😱 laptop up and running. Good luck with your Windows 10 laptop, I may hold off on upgrading for a wee while yet!
Update ruined my win8 PC. Did one and then removed it as things didn't work out. Still ok but insisted on updating. Same thing happened. Next one, ceased to work after the update was undone. LOL My previous win laptop was win 2k. I mostly use a desktop but bit of a problem currently for audio work. I don't intend to connect the new one to the web!!!,
Attention Space Fans! We can take a break from Gravity for the moment, though I have many new discoveries to reveal about The Big Bang, Cosmic inflation an' all that. 😀
Exciting Live Feed tomorrow (Wednesday 23 August) from The Moon:
https://www.space.com/india-chandrayaan-3-moon-landing-livestream
08.34 ET for the American cousins, 12.34 GMT aka UTC for us in the UK, which is 13.34 BST if I have calculated it right.
I love the live stuff. You never know if it will work, or crash and burn! This mission is looking for water in the cold and shadowy craters at the South Pole of The Moon. They have a cute little battery powered Rover set to trundle around for a couple of weeks.
Only thing I don't get is why this probe is landing at 69.367621 S, 32.348126 E. Surely a child of ten knows that is nowhere near the South Pole of The Moon? 🙁
I have already established the cause of the unfortunate Luna 25 crash on Sunday:
https://www.hindustantimes.com/worl...in-reason-for-failure-is-101692666214686.html
This put the spacecraft's Perigee orbit 6 miles below the surface of the Moon. With predictable results.
Who designs these missions! 🙄
Exciting Live Feed tomorrow (Wednesday 23 August) from The Moon:
https://www.space.com/india-chandrayaan-3-moon-landing-livestream
08.34 ET for the American cousins, 12.34 GMT aka UTC for us in the UK, which is 13.34 BST if I have calculated it right.
I love the live stuff. You never know if it will work, or crash and burn! This mission is looking for water in the cold and shadowy craters at the South Pole of The Moon. They have a cute little battery powered Rover set to trundle around for a couple of weeks.
Only thing I don't get is why this probe is landing at 69.367621 S, 32.348126 E. Surely a child of ten knows that is nowhere near the South Pole of The Moon? 🙁
I have already established the cause of the unfortunate Luna 25 crash on Sunday:
https://www.hindustantimes.com/worl...in-reason-for-failure-is-101692666214686.html
This put the spacecraft's Perigee orbit 6 miles below the surface of the Moon. With predictable results.
Who designs these missions! 🙄
I read that the Chandrayaan landing is to be attempted in an area between 68 and 70° S and 31 and 33° E near the moon’s south pole, with an alternate landing site within an area between 68 and 70° S and 16 and 18° W.
The Chandrayaan-3 lander is currently searching for a safe landing spot, one without boulders and deep trenches.