Islander

From Wikipedia...

Two spectroscopic companions have been proposed to the red supergiant star. Analysis of polarization data from 1968 through 1983 indicated a close companion with a periodic orbit of about 2.1 years. Using speckle interferometry, the team concluded that the closer of the two companions was located at 0.06″±0.01″ (≈9 AU) from the main star with a position angle of 273 degrees, an orbit that would potentially place it within the star's chromosphere. The more distant companion was estimated at 0.51″±0.01″ (≈77 AU) with a position angle of 278 degrees.^[69][70] Further studies have found no evidence for these companions or have actively refuted their existence,^[71] but the possibility of a close companion contributing to the overall flux has never been fully ruled out.^[72] High-resolution interferometry of Betelgeuse and its vicinity, far beyond the technology of the 1980s and '90s, have not detected any companions.^[16][73]

Let me say it again.

Betelgeuse is not a threat to Earth or life on Earth.

Oh and a quote from that article:

"But that doesn’t mean – contrary to scare stories in the media – that the core has collapsed, and is about to trigger a supernova. For a start, it would implode in literally a matter of seconds, and the shock wave would rip through Betelgeuse before the outer layers have a chance to fade. So if this dimming were a harbinger of doom, Betelgeuse would have self-destructed weeks ago.

Betelgeuse will go supernova one day, and rival the Full Moon in brightness – but probably not for 100,000 years."

None of the possible outcomes are a threat to Earth.  

The most likely outcome is that it will eventually return to normal brightness.

Everything has to happen some time, and not all of the possibilities are happening.  The scientific consensus seems to be that the dimming isn't that unusual unless it persists.  Even if it does persist it's more likely that it'll return at some point.  A supernova is unlikely, but in the event it happens in our lifetime, it's not a threat.  It's also more likely to produce a neutron star than a black hole but again, neither are dangerous to Earth.

4 minutes ago, Damien1975 said:

I am really confused with all this to be honest. 
 

if it starts illuminating again then is will become a supernova and it’s at a safe distance 

if it continues dimming it will explode into a black hole.  Which at the distance is dangerous 
 

So far with all the dimming it looks like it’s in the process of becoming a black hole. Both scenarios are very very close to happening

 

It does sound like you're confused.

If it returns to normal brightness then it'll carry on as normal, no supernova just a red supergiant star.

If it continues dimming, then something new is happening but the likelihood is that the effect will be down to expulsion of material which partially obscures the star and eventually it'll brighten again.

If it were to become a supernova, then it wouldn't affect us apart from being visible in daytime and eventually changing the shape of Orion forever.  To become a black hole it has to undergo catastrophic gravitational collapse and that would produce a supernova.  It's still not  dangerous to Earth though.

Now that would be a sight to behold

10 minutes ago, Damien1975 said:

It is only 600 to 800 lights years away isn’t that daily close if it becomes a black hole. The closest to earth is like 3000 light years, so this would become the closest to us 

mans i read we will know by February 21

Two things, the net gravitational effect on Earth will be zero, and nobody can predict the exact date of a supernova occurring.

No, it really isn't.  The more sensationalist press might run with that but it's not mainstream scientific opinion.

Red supergiants are inherently variable.   Betelgeuse has dimmed somewhat but that's likely to be caused by material being expelled, again a feature of red supergiants.

Seriously, Betelgeuse is too distant to affect us whatever happens to it.

It's more likely that it'll brighten again and return to business as usual than become a supernova.

16 minutes ago, Damien1975 said:

So what would happen if it became a black hole instead?

 

also why is the date feb 21 important for this 

Why would a stellar merger become a black hole?  Also, where did the date pop up from?

I'm really not sure what you're looking for...

3 minutes ago, saac said:

Damien as others have said it's a billion times 9 light years ie 9 billion lights years.   Even with a reasonable margin of error I think my holidays for next week are safe against the bubble of doom  

Jim 

Better pack a waterproof and umbrella just to be on the safe side

On 07/02/2020 at 16:57, Damien1975 said:

I don’t understand exactly don’t these bubbles expanding and coming at us have a deadly effect on the planet like end of earth

They aren't coming at us.  Quote from the article:

"The symmetry of the bubbles billowing above and below the galaxy suggests they were formed by an extremely energetic explosion near the supermassive black hole at the center of the Milky Way. The most likely explanation is a flare up in the black hole’s activity as it gobbled up extra nearby material and burped out other particles and radiation."

Note the first statement in the quote "above and below the galaxy" not laterally and towards the arms.  

1 hour ago, Damien1975 said:

This is the number calculated 9.7847e+9 is that 9 point something light years 

No.  The e+9 means that the decimal point shifts 9 places to the right.

As others have already said, a parsec is 3.26. light years.  A Megaparsec is a million times that.  

It's the density that matters and the density that causes the curvature of spacetime to increase.  When the star runs out of fuel, there is no longer sufficient pressure of fusion to hold the outer layers up against gravity, the star is no longer in hydrostatic equilibrium and the outer layers rapidly collapse into the core which then further collapses until the density is infinite.  

18 minutes ago, Alien 13 said:

This puzzles me too for example if our sun suddenly transformed into a black hole of the same mass would our orbit change? 

Alan

No.  The Earth would experience the same gravitational pull as it did before the Sun collapsed (which it actually couldn't - too little mass available).  It would continue to orbit normally.  

This is a gross oversimplification but...

Remember that the mass if he star has collapsed into a point of infinite density and this causes the curvature of spacetime at the point of singularity to become infinite as well.  It's this that prevents anything from escaping.   Think of it this way.  A photon entering the region outside the black hole's influence can travel in any direction.  As it approaches the black hole, the directions of travel available to it begin to disappear until it can only head into the singularity itself.  That point is defined by the event horizon.

23 hours ago, newbie alert said:

Thanks for the advice,  I've already got the sharpsand, just need to get the aggregate.. which again is another thing to dither over, 10 or 20mm ? 

14mm? 

I'd use a C20 mix.  I bag cement to 2 of sand and 4 of aggregate.  For 1 cubic metre, you'd need 320kg cement, 640 kg sand and 1280kg of aggregate (10-20mm).  Oh and about 300 litres of water.  For that quantity it's worth considering a readimix delivery.

I've never been impressed by the 1m3 isolated cube for a pier foundation argument.  When I eventually get round to building my own, I'll just pour a 150mm thick slab for the whoe thing and build a pier from concrete blocks on top of it. 

ETA

Oh and I'm on glacial till i.e clay with rocks in it.

If you do decide to buy rather than build, I'd recommend the Davis Vantage Pro 2.  I've been running one for years and apart from 2 sets of anemometer bearings, it's been faultless.  There are people on the various forums (Cumulus, WXForum) that make aftermarket data loggers for interfacing to Cumulus.  The initial outlay is high but the reliability compensates for that.

2 hours ago, Skipper Billy said:

You may well be right - I am not a native Gaelic speaker but a Gaelic speaking pal of mine told me that's what to put - he might be winding me up - it could say 'Public Toilet' for all I know !!!

It's nothing that bad - beag means small or little.  Quite appropriate for such a petite and smart build really

On 3/8/2016 at 17:27, Skipper Billy said:

Its going to have a name above the door - 'Cu Beag' - its a bit tongue in cheek - its Gaelic for Big Dog !

Cu Mhor surely

A couple of pairs of Carl Zeiss Jenoptem 8x30s - the proper DDR ones.  Nice and light and superb optical quality

A chap mentioned on TV ht he took time to reply to all letters and enquiries, from whoever and wherever they came. From the many wishes and replies I have read on here, I know Sir Patrick had a passion and integrity that was beyond and above anyones expectations.

He certainly did. I wrote to him many times when I was much much younger and he answered every letter personally and fully. I had the good fortune to be invited to his house and went with my father. He was a thoroughly nice man, didn't talk down to me or patronise me but rather treated me as an equal and fellow amateur even though I wasn't even in my teens at the time. He fostered my lifelong interest in astronomy and for that I'll always be grateful and remember him very fondly. He's almost single-handedly responsible for astronomy being the popular hobby it is IMO. His work on the moon was pioneering - it was used by the Americans to plan moon missions. Uniquely eccentric yet modest and unassuming, a real gentleman scientist. He'll be greatly missed. R.I.P. Patrick and thank you.

Just use the blower - the brush can pick up and harbour abrasive particles. To be honest, blower brushes generally aren't as powerful as proper rocket blowers.

Dust shouldn't get between the elements and if it is, it's probably been there since manufacture. Don't attempt to separate them!

The clue is in the name - there are two lens elements in the objective of a doublet

If you remove the objective you'll probably have to collimate - it really isn't worth it unless the dust is seriously affecting your viewing.