Astronomical News

OneWingedBird

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OneWingedBird

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Hugely worth watching too, there's a crude video clip later on made up of images of the black hole taken over the period of a week and showing fluctuations in the accretion disk.

 

gerhard1

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Found in Papua New Guinea.

A new study by two Harvard researchers reveals the cosmos may have already deposited the first such far-flung visitor onto our doorstep five years ago in 2014, when a small meteor crashed into Earth near Papua New Guinea in the South Pacific. According to their research, this 1.5-foot-wide object most likely came all the way from another solar system.

Think about it: An object, originating untold miles and millennia away, just plopping into the sea. The implications are as vast and mysterious as the wide open space from which it came.

"Almost all of the objects that hit the Earth originate for the solar system," explains Dr. Abraham Loeb, the chair of the Department of Astronomy at Harvard University, and the co-author of the study. "They are made of the same materials that made the solar system. Those that are interstellar originate from another source. It's sort of like getting a message in a bottle from a distant location. We can actually examine it, just as if we were walking on the beach and looking at the seashells that are swept ashore, we could learn something about the ocean."


Continued:
https://www.msn.com/en-us/news/tech...cations-are-fascinating/ar-BBW2dXM?li=BBnb7Kz
 
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Comfortably Numb

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New Hubble measurements confirm universe is expanding faster than expected

Date: April 25, 2019

New measurements from NASA's Hubble Space Telescope confirm that the Universe is expanding about 9% faster than expected based on its trajectory seen shortly after the big bang, astronomers say.

https://www.sciencedaily.com/releases/2019/04/190425104128.htm
 

OneWingedBird

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Makes me wonder how accurate they are at determining the % of dark matter at vast distances away? Sound theoretical
Galaxies need to have a certain amount of mass relative to the velocities of the stars in them otherwise they would fly apart, at any distance the deficit is deemed to be dark matter. Or something else we totally don't understand is going on.
 

Jim

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Galaxies need to have a certain amount of mass relative to the velocities of the stars in them otherwise they would fly apart, at any distance the deficit is deemed to be dark matter. Or something else we totally don't understand is going on.
All highly theoretical (not wrong, just not provably in an absolute scientific manner). No one knows for sure if dark matter holds galaxies, etc together and maintain the velocities (speed) needed for their present position in the universe.
So arouse the theory of dark matter. Which provides a convenient answer for this conundrum.

The following NASA article discusses dark matter and some uncertainty surrounding it.
https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy
 
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Comfortably Numb

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I wondered if someone could maybe please help me out here?

Trying to explain - 7-year-old granddaughter - why stars were actually distant suns in our galaxy, which is one of many others.

'So, how many stars are there in the universe, Grampa'?

Realised, I didn't actually know the estimate... anyone?

Isn't the estimated answer, almost an unfathomable amount? o_O
 

Graylien

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The short answer seems to be that it's impossible to know.

We know the universe formed 13.8 billion years ago. That means that theoretically we can detect light from stars and galaxies up to 13.8 billion light years in any direction.

However in practical terms the number of stellar objects we can actually detect depends on the sensitivity of our equipment. Since this is constantly improving, we are constantly seeing things we couldn't see before.

However the observable universe is much smaller than the actual universe, since spacetime itself can expand faster than the speed of light.

The consensus seems to be that the early universe expanded extremely rapidly but has since slowed. The precise figures are subject to debate, and so consequently is the total size of the universe and the amount of matter it may contain.

With the naked eye you can actually only see a few thousand stars under ideal viewing conditions (i.e a clear sky with no light pollution).

As for how many stars there are in the so-called observable universe, everyone seems to agree there will actually be far more than our equipment will ever be able to detect.

Current guestimates generally suggest there are around 2 trillion galaxies each containing around 100 million stars.

So whatever that comes to. 2e20 apparently. What's that in English?
 

Comfortably Numb

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The consensus seems to be that the early universe expanded extremely rapidly but has since slowed. The precise figures are subject to debate, and so consequently is the total size of the universe and the amount of matter it may contain.
Seriously, so grateful.

I was surprised that the recent evidence - Universe is expanding faster than mathematical models predicted - didn't attract more discussions.

If it's, 'back to the drawing board', is that not somewhat fundemental?
 

Graylien

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Yes, that does suggest there's something pretty fundamentally inaccurate or missing in our current model of the development of the universe
 

Comfortably Numb

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Yes, that does suggest there's something pretty fundamentally inaccurate or missing in our current model of the development of the universe
What I predominantly don't understand, is... why we are alive in such an unfathomable cosmos, yet still given enough intelligence to try and figure it out...

This and quite a few other things... meaning of life and all that...

201955_112216557.jpg
 

eburacum

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In the very early universe the rate of expansion increased to a fantastic rate, but this very very fast expansion only lasted a fraction of a second (the so-called Inflation Era). Subsequently expansion slowed almost to a halt. Since that time, expansion has been slowly speeding up again, but it seems that the rate of increase in expansion in the current era is slightly higher than was previously believed. What this means for the future is anyone's guess, but it may mean that we a re heading for a Big Rip scenario.
https://en.wikipedia.org/wiki/Big_Rip
 
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