Ultimate space simulation software

 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

01 Aug 2019 12:17

Thought this was interesting, I am rooting for Einstein to go down :P

https://www.sciencedaily.com/releases/2 ... 150408.htm


"Einstein's right, at least for now," said Ghez, a co-lead author of the research. "We can absolutely rule out Newton's law of gravity. Our observations are consistent with Einstein's theory of general relativity. However, his theory is definitely showing vulnerability. It cannot fully explain gravity inside a black hole, and at some point we will need to move beyond Einstein's theory to a more comprehensive theory of gravity that explains what a black hole is."

http://www.astronomy.com/news/2019/07/c ... -expansion

The latter is something I believe we have already been discussing.
 
User avatar
Watsisname
Science Officer
Science Officer
Posts: 1759
Joined: 06 Sep 2016
Location: Bellingham, WA

Science and Astronomy News

03 Aug 2019 01:01

A-L-E-X wrote:
Source of the post Thought this was interesting, I am rooting for Einstein to go down

A lot of us would like to see some signs of general relativity breaking down under extreme conditions, since that would give clues to a more complete theory.   It isn't at all a new realization that it must break down somewhere -- even in the 1960s era of black hole research it was understood that this must happen deep inside them (near the singularity if it isn't spinning, or near the inner event horizon if it is).  

The main reason we have not yet seen signs of GR breaking down is because we are not yet able to test it precisely enough in a regime where we expect it to break down.  It would have been exciting if we saw it break down close to black holes in LIGO or EHT observations, but nope!  It is still very accurate in those conditions. :)
 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

09 Aug 2019 10:30

Watsisname wrote:
A-L-E-X wrote:
Source of the post Thought this was interesting, I am rooting for Einstein to go down

A lot of us would like to see some signs of general relativity breaking down under extreme conditions, since that would give clues to a more complete theory.   It isn't at all a new realization that it must break down somewhere -- even in the 1960s era of black hole research it was understood that this must happen deep inside them (near the singularity if it isn't spinning, or near the inner event horizon if it is).  

The main reason we have not yet seen signs of GR breaking down is because we are not yet able to test it precisely enough in a regime where we expect it to break down.  It would have been exciting if we saw it break down close to black holes in LIGO or EHT observations, but nope!  It is still very accurate in those conditions. :)

Wat, have you been watching the excellent History of Astronomy series on PBS?  It is absolutely amazing!  And the Planets series right after that.  The graphics they show blow my mind!   I was thinking of you guys while watching both.  PBS quality is definitely way higher than any commercial TV network.  Their news too- they had a scientist on who works with the UN who was talking about how our land management techniques and the overreliance on meat is destroying the environment- a new study came out about that recently?  They said we have about 10-12 years to change our ways before the damage is irreparable.
 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

09 Aug 2019 14:03

 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

09 Aug 2019 14:22

A-L-E-X wrote:
Watsisname wrote:
A-L-E-X wrote:
Source of the post Thought this was interesting, I am rooting for Einstein to go down

A lot of us would like to see some signs of general relativity breaking down under extreme conditions, since that would give clues to a more complete theory.   It isn't at all a new realization that it must break down somewhere -- even in the 1960s era of black hole research it was understood that this must happen deep inside them (near the singularity if it isn't spinning, or near the inner event horizon if it is).  

The main reason we have not yet seen signs of GR breaking down is because we are not yet able to test it precisely enough in a regime where we expect it to break down.  It would have been exciting if we saw it break down close to black holes in LIGO or EHT observations, but nope!  It is still very accurate in those conditions. :)

Wat, have you been watching the excellent History of Astronomy series on PBS?  It is absolutely amazing!  And the Planets series right after that.  The graphics they show blow my mind!   I was thinking of you guys while watching both.  PBS quality is definitely way higher than any commercial TV network.  Their news too- they had a scientist on who works with the UN who was talking about how our land management techniques and the overreliance on meat is destroying the environment- a new study came out about that recently?  They said we have about 10-12 years to change our ways before the damage is irreparable.

And be sure to read this!
https://journals.aps.org/prl/abstract/1 ... 123.041601
We may be a step closer to a theory of quantum gravity!

The new study — published in the journal Physical Review Letters — provides a solid theoretical framework to discuss modifications to the Unruh effect caused by the microstructure of space-time.
Eduardo Martin-Martinez, an assistant professor in Waterloo’s Department of Applied Mathematics, elaborates on the team’s work: “What we’ve done is analyzed the conditions to have Unruh effect and found that contrary to an extended belief in a big part of the community thermal response for particle detectors can happen without a thermal state.”
The team’s findings of importance because the Unruh effect exists in the boundary between quantum field theory and general relativity, and quantum gravity, which we are yet to understand.
“So, if someone wants to develop a theory of what’s going on beyond what we know of quantum field theory and relativity, they need to guarantee they satisfy the conditions we identify in their low energy limits.”

It predicts that an observer in a non-inertial reference frame — one that is accelerating — would observe photons and other particles in a seemingly empty space while another person who is inertial would see a vacuum in that same area.
In other words; a consequence of the Unruh effect is that the nature of a vacuum in the universe is dependant on the path taken through it.
As an analogy, consider a universe with a constant temperature of zero and in which, no heat arises from the effects of friction or kinetic energy contributions. A still thermometer would have its mercury-level sat permanently at zero.
But the Unruh effect posits that if that thermometer was waved from side-to-side, the temperature measured would no longer be zero. The temperature measured would be proportional to the acceleration that the thermometer undergoes.
Raúl Carballo-Rubio, a postdoctoral researcher at SISSA, Italy, explains further: “Inertial and accelerated observers do not agree on the meaning of ‘empty space.
 “What an inertial observer carrying a particle detector identifies as a vacuum is not experienced as such by an observer accelerating through that same vacuum. The accelerated detector will find particles in thermal equilibrium, like a hot gas.”
He further explains that as a result of this, it is reasonable to expect that any new physics that modifies the structure of quantum field theory at short distances, would induce deviations from this law. 
 
User avatar
PlutonianEmpire
Pioneer
Pioneer
Posts: 500
Joined: 02 Nov 2016
Location: MinneSNOWta
Contact:

Science and Astronomy News

26 Aug 2019 06:16

Tbh, the only reason I want Einstein to go down is so we can finally flip the bird at all the nay-sayers who say no to time-dilationless warp drive. :P
Specs: Dell Inspiron 5547 (Laptop); 8 gigabytes of RAM; Processor: Intel® Core™ i5-4210U CPU @ 1.70GHz (4 CPUs), ~2.4GHz; Operating System: Windows 7 Home Premium 64-bit; Graphics: Intel® HD Graphics 4400 (That's all there is :( )
 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

30 Aug 2019 03:18

I found some interesting news stories, so I'll just list them here with small captions.

https://www.livescience.com/quantum-gra ... ffect.html

quantum gravity could reverse cause and effect

https://www.quantamagazine.org/possible ... -20190828/

possible detection of a black hole that "should not" exist

https://www.livescience.com/65743-black ... -life.html

radiation from black holes may create life

https://www.livescience.com/hubble-constant-discrepancy-explained.html


hubble discrepancy explained

https://www.livescience.com/64304-dark-fluid-negative-mass-dominates-universe.html

dark fluid negative mass may dominate the universe

there were many other interesting articles in Live Science, including physicists' ideas on how to build a stable wormhole using cosmic strings and the element with the longest half life, xenon-124 (18 hextillion years!) being used to detect dark matter, etc.
 
User avatar
Cantra
Pioneer
Pioneer
Posts: 334
Joined: 02 Nov 2016
Location: Sedna

Science and Astronomy News

12 Oct 2019 19:52

Turns out that Saturn has 20 or so new moons. Making it have 82 moons now.
 
User avatar
JackDole
Star Engineer
Star Engineer
Posts: 1585
Joined: 02 Nov 2016
Location: Terra

Science and Astronomy News

12 Oct 2019 21:15

Cantra wrote:
Source of the post Turns out that Saturn has 20 or so new moons. Making it have 82 moons now.

That's old news.
NewSaturnMoons.sc
(17.24 KiB) Downloaded 11 times

(They'll be officially in SpaceEngine soon.)
JackDole's Universe 0.990: http://forum.spaceengine.org/viewtopic.php?f=3&t=546
JackDole's Archive: http://forum.spaceengine.org/viewtopic.php?f=3&t=419
JackDole: Mega structures ... http://old.spaceengine.org/forum/17-3252-1 (Old forum)
 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

13 Oct 2019 02:10

JackDole wrote:
Cantra wrote:
Source of the post Turns out that Saturn has 20 or so new moons. Making it have 82 moons now.

That's old news.
NewSaturnMoons.sc
(They'll be officially in SpaceEngine soon.)

I hope all your add-ons find there way into a single download release on Steam lol.
 
User avatar
Cantra
Pioneer
Pioneer
Posts: 334
Joined: 02 Nov 2016
Location: Sedna

Science and Astronomy News

13 Oct 2019 18:53

JackDole wrote:
Cantra wrote:
Source of the post Turns out that Saturn has 20 or so new moons. Making it have 82 moons now.

That's old news.
NewSaturnMoons.sc
(They'll be officially in SpaceEngine soon.)

May be old news though it is interesting nevertheless. Just found out about it yesterday.
 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

29 Oct 2019 05:29

Paper from 2018 by Oxford University and funded through the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program.  Curious what others think about this updated approach!

 

https://arxiv.org/pdf/1806.02404.pdf

 

Cutting to the conclusion, here's their take --

 

"We have seen that a Fermi paradox arises if we combine a high and extremely confident prior for the number of civilizations in our galaxy with the absence of evidence for their existence. The high confidence that causes this clash typically results from applying a Drake-like model using point estimates for the parameters. These estimates, however, make implicit knowledge claims about processes (especially those connected with the origin of life) which are untenable given the current state of scientific knowledge.When we take account of realistic uncertainty, replacing point estimates by probability distributions that reflect current scientific understanding, we find no reason to be highly confident that the galaxy (or observable universe) contains other civilizations, and thus no longer find our observations in conflict with our prior probabilities. We found qualitatively similar results through two different methods: using the authors’ assessments of current scientific knowledge bearing on key parameters, and using the divergent estimates of these parameters in the astrobiology literature as a proxy for current scientific uncertainty.When we update this prior in light of the Fermi observation, we find a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). ’Where are they?’— probably extremely far away, and quite possibly beyond the cosmological horizon and forever unreachable."

 

Read this for an alternate viewpoint:

https://www.cloudynights.com/articles/c ... adox-r3162
Last edited by A-L-E-X on 29 Oct 2019 05:36, edited 1 time in total.
 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

29 Oct 2019 05:36

Actually being alone is good news, it means lots of potentially habitable worlds to colonize- a la the Asimovian vision of our galaxy!
 
User avatar
Watsisname
Science Officer
Science Officer
Posts: 1759
Joined: 06 Sep 2016
Location: Bellingham, WA

Science and Astronomy News

29 Oct 2019 11:05

A-L-E-X wrote:
Source of the post Paper from 2018 by Oxford University and funded through the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program.  Curious what others think about this updated approach!

Yes, we previously discussed it here on the forum as well.  

tl;dr, they basically just fit some assumed shape of probability distribution across the various estimates for the parameters in the Drake equation that are found in the literature, and from that make a statement of the overall probability by using the standard principles of error analysis. Error analysis is a crucial tool in science (and is also not at all a new approach), but using it in this way to draw that conclusion is stuuuuupidError analysis is something that we do over a distribution of measurements.  Of course if you fit a probability distribution across all made-up estimates which include a lot of extremely pessimistic ones, then your conclusion will also be pessimistic.  It does not represent any new measurements or insights to the frequency of life-bearing worlds in the universe.
 
A-L-E-X
Star Engineer
Star Engineer
Posts: 1728
Joined: 06 Mar 2017

Science and Astronomy News

01 Nov 2019 09:18

Watsisname wrote:
A-L-E-X wrote:
Source of the post Paper from 2018 by Oxford University and funded through the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program.  Curious what others think about this updated approach!

Yes, we previously discussed it here on the forum as well.  

tl;dr, they basically just fit some assumed shape of probability distribution across the various estimates for the parameters in the Drake equation that are found in the literature, and from that make a statement of the overall probability by using the standard principles of error analysis. Error analysis is a crucial tool in science (and is also not at all a new approach), but using it in this way to draw that conclusion is stuuuuupidError analysis is something that we do over a distribution of measurements.  Of course if you fit a probability distribution across all made-up estimates which include a lot of extremely pessimistic ones, then your conclusion will also be pessimistic.  It does not represent any new measurements or insights to the frequency of life-bearing worlds in the universe.

Yes!  Exactly- thats why the fellows at Cloudy Nights pointed out that you can't do that sort of analysis when your sample size is only one (that is, the Earth!)  The fact we only have our own planet to form any basis for what life elsewhere might be like (let alone "intelligent" life).

Who is online

Users browsing this forum: Watsisname and 1 guest