Does this explain what generates gravity?

@Galu, it was JADE Goody. Bless 'er.

Nova hunting postponed due to inclement weather. But I have two new books, hot off the presses, and an ace arty video to watch. I am excited.

DSCN0018.JPG


You can guess I have started with the new Mickey Haller book (aka The Lincoln Lawyer, which you can find on Netflix TV too), who is currently employing Harry Bosch as his driver and second investigator. :)

I am not too sure how the Methuselah Star can be 0.81 Sols mass, 5X brighter than the Sun and 12 Bn years old, but guess it's on the edge of Red Giant expansion...

It's moving rapidly, approx 180 Km/s which is high. It's a sort of living fossil of the early Universe in our own environs.

There are whole groups of stars near to us moving together. An example is most of the stars in Ursa Major:

Ursa Major Photo.jpg


Ursa Major Moving Group.jpg


Mostly hot young blue (Spectroscopic A) stars and tending bigger than our Sun.

Zeta is extremely interesting. Mizar forms a naked eye double with Alcor, but a modest telescope, as possessed by Galileo, easily saw the primary is double, which BTW takes thousands of years to revolve.

I saw this years back with a 60mm telescope. It looks like this:

Mizar and Alcor.jpg


In fact Mizar's two stars reveal themself to be spectroscopic binaries too. These revolve in about 20 days. So it's a sextuple system overall, since Alcor is a double too.

https://en.wikipedia.org/wiki/Mizar

https://en.wikipedia.org/wiki/Alcor_(star)

I don't know the period of Mizar and Alcor revolving, but they are about a light year apart.

Apparently there are various ways a star can get to high velocity. One is if a binary stars get near a black hole, one star is swallowed, the other ejected.

I was also pondering the time scale of Stellar Evolution. Big stars burn out fast. Our Sun is more sedate but eventually forms a Red Giant:

Sun Evolution.jpg


https://science.nasa.gov/universe/e...-solar-twin-may-help-locate-rocky-exoplanets/

I'll stop there. Another blockbuster post!

Best, Steve.
 
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I thought it was an uninformative image, TBH. I continue my healthy obsession to claim a World First in spotting the Nova in Corona Borealis.

Alas, not tonight:

22 May 22.20 Hrs Corona Borealis.png


A full moon and thin cloud is making this difficult. But a good enough image. That is Arcturus to the right.

I have discovered that nearby Spica in Virgo is a likely candidate for the nearest Type II Supernova!

https://en.wikipedia.org/wiki/Spica

Sometime in the next 3M years, Can't wait!

It's a whopping ellipsoidal double Type B Star at 250 Ly and 4,000 times brighter than the Sun. Only 12M years old, as happens with big stars.

Spica forms a nice Spring Triangle with Arcturus and Denebola in the tail of Leo. Easily found too:

Arc to Arcturus and Spike to Spica.png


My sister is a Virgo in an Astrological sense:

Virgo and Arcturus.png


A pretty constellation.

Best, Steve.
 
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You need a good imagination to think that constellations are actually shaped like recognisable objects or animals.

There's no better example than this image of constellation Bongo as imagined by Richard Feynman:

1716417985296.png


Maybe not all that unimaginable though:

1716418970690.png

Bongo

:giggle:
 
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No T CrB Nova tonight. I feel it's just a question of when, not if.

Vega, Arcturus and CrB.jpg


I have dabbled in Windows Paint program to show what I am hoping to see soon:

Vega, Arcturus and T CrB.jpg


Conditions tonight were made difficult by cloud, the full moon and street lighting but the full image was rather good.

I could pick out the yellow and orange stars, and even think I could see Messier 13 (M13) Globular cluster in Hercules.

This is estimated at 12Bn years old and 25,000 Ly away within our galaxy. 100,000 Stars.

sky_chart_600.jpg


The attached big image shows Vega and Arcturus bracketting the region of interest including what I think is M13. Further South you will find Sagittarius, Ophiucus and Scorpio. Best, Steve.
 

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Ah!

Spiral galaxy IC 342 resides about 10.7 million light-years from Earth and spans the width of a full moon in the sky.

If it were not obscured by the Milky Way's gas and dust, we would be able to look up and see it as one of the brightest objects in the sky.

But Euclid, with its infrared eyes, sees right through the gas and dust for us!
 

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Don't see what all the Euclid fuss is about! This M78 picture was taken on the 2.2m telescope in Chile:

M78 2.2m Chile Composite.jpg


https://en.wikipedia.org/wiki/Messier_78

OK, Infra-red is a problem here on earth. Greenhouse gases an' all that.

But give me a star map and I can find most things:

Orion constellation.jpg


I should be able to take a snap like this on my modest Nikon D60 camera:

Orion's Belt.jpg


Might need a bigger lens, come to think of it. Ah, the expense! :(
 
Very cloudy tonight, but I found a gap in the clouds:

T Corona Borealis.png


Corona Borealis 270554 0042 Hrs.png


I fear the forum software has compressed this image of Corona Borealis to smear out the fainter stars somewhat.

Because the original jpeg shows Pi and Eta either side of Theta clearly. But you can see that Epsilon and Delta on the left are reddish.

And also a faint mag. 6 star where R CrB ought to be. I like this map because it shows brightnesses, and I am at the limit of human eyesight in the photo.

R Corona Borealis.png


R Corona Borealis disappeared down to magnitude 15 for 18 years until recently. Now back at 6. Gets regularly obscured by ejected carbon dust.

Still waiting for T CrB to blow near Epsilon. It's fun, because it could pop to magnitude 2 very suddenly AFAIK. Take a few hours.

Meanwhile Ethan Siegel has a nice new article on the Expanding Universe.

https://bigthink.com/starts-with-a-bang/we-expand-with-universe/?utm_source=pocket-newtab-en-gb

I realised that if you look into the very far away stuff like the James Webb Telescope often does, you are not seeing it how it is, but how it was back then!

It's now all much bigger! Which is all a bit mind-boggling.

Now it is made of:

  • 68% dark energy, behaving as the cosmological constant examined by de Sitter,
  • 27% dark matter, which acts like a form of mass but that doesn’t experience any interaction other than gravity,
  • 4.9% normal matter, which includes protons, neutrons, electrons, and everything they come to form,
  • 0.1% neutrinos, which behave as radiation when the Universe is hot and young but then behave as matter when the Universe is cold and old,
  • and 0.01% photons, which always behave as radiation.

Now I just did a back of a beermat calculation, and I made it:

* 0.002% electrons

Which surprised me, but seems about right if you think that protons are about 2,000 times heavier than electrons and most of the matter is hydrogen. Neutrons don't change the ballpark estimate much.
 
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