Author Topic: Deep Space and Interplanetary Exploration - The Universe is Timeless (Read 178645 times)

worktroll · « **Reply #420 on:** 29 January 2016, 15:04:09 »

See also "time-like curves" in that context, but admittedly you're talking more black hole than neutron star at that point.

Weirdo · « **Reply #421 on:** 29 January 2016, 15:17:10 »

Geez, and I thought my attempt to play Mechwarrior 2 over dial-up was laggy...

Maingunnery · « **Reply #422 on:** 29 January 2016, 15:31:05 »

Quote from: ANS Kamas P81 on 29 January 2016, 14:42:56

Speaking of relativistic physics, found something I'd been looking for - millisecond pulsar rotation rates and the idea of frame dragging. Imagine a neutron star spinning at a little over 42,000rpm. And imagine how fast that it's moving at the equator. Now imagine what that's doing to the very fabric of space time, twisting and wrapping it around the star like taffy around a mixing hook.

Now imagine passing through that frame-dragged space.

Doesn't that also polarize the surrounding space?

kato · « **Reply #423 on:** 31 January 2016, 16:35:44 »

Planned development of space-based observatories in the next 15 years, as planned out currently:

Operational: HST (NASA, LEO), GAIA (ESA, SEL2), SWIFT (NASA, LEO)

2016 - ASTRO-H online (JAXA, SSO), HXMT online (CNSA, SSO)
2017 - CHEOPS online (ESA, SEL2), TESS online (NASA, HEO)
2018 - JWST online (NASA/ESA, SEL2)
2019 - ASTRO-H offline (JAXA, SSO), GAIA offline (ESA, SEL2), TESS offline (NASA, HEO)
2020 - EUCLID online (ESA, SEL2), HXMT offline (CNSA, SSO), HSToffline (NASA, LEO)
2021 - SVOM online (CNSA, SSO)
2022 - CHEOPS offline (ESA, SEL2)
2023 -
2024 - WFIRST online (NASA, GEO), PLATO online (ESA, SEL2), SVOM offline (CNSA, SSO)
2025 - ATLAST possible (NASA, SEL2), EUCLID offline (ESA, SEL2), CV M4 possible* (ESA, SEL2)
2026 -
2027 -
2028 -
2029 -
2030 - WFIRST offline (NASA, GEO), PLATO offline (ESA, SEL2)

* M4 candidates: 66% chance for ARIEL or XIPE observatories

Notes:
Not counting NANO-JASMINE given its likely rather short time of operation.
Not putting SWIFT offline date in there since it could fail at any time. Since 2010 or so.
Not putting any ISS-based missions in there (e.g. EUSO, NICER, CREAM, MAXI).
Not putting any Russian missions in there due to unreliability of funding (e.g. SPEKTR-RG, SPEKTR-UV).

(copying over from a post i made on another forum)

ANS Kamas P81 · « **Reply #424 on:** 10 February 2016, 13:53:00 »

Do we have any physicists around that could take a look at this one? Preferably with access to the paper itself.
http://www.forbes.com/sites/johnfarrell/2016/02/10/black-holes-could-be-gateways-after-all/#39452caf54ef
Somewhere, the Gunbuster creators are giggling to themselves...

worktroll · « **Reply #425 on:** 10 February 2016, 16:57:39 »

Paywalled. I stick on a blank Welcome screen ... :(

Daryk · « **Reply #426 on:** 10 February 2016, 19:23:56 »

I get caught in an endless of loop of "continue to site" pages... :P

worktroll · « **Reply #427 on:** 10 February 2016, 19:57:09 »

You see? It's a gateway after all! Click long enough, and ... my God, it's full of stars!

Daryk · « **Reply #428 on:** 10 February 2016, 20:18:19 »

LOL! Now I see why they promoted you... ;D

For ANS, can you give us a title of the paper itself, or at least the author? My timing was off in college (Tensor Calculus was only offered every other year, and General Relativity had that as a prerequisite), but I did take some special relativity that involved reading some Feynman.

worktroll · « **Reply #429 on:** 10 February 2016, 20:27:51 »

There was movement at the station, for the word had got around ... LIGO may have picked up traces of gravitational waves! Press conference planned for tomorrow US time.

Gonna be big - a new window opening up, new things to 'see', new suprises no doubt.

Daryk · « **Reply #430 on:** 10 February 2016, 20:42:37 »

Gravitational waves!? Finally!! O0

ANS Kamas P81 · « **Reply #431 on:** 10 February 2016, 22:01:01 »

No paywall here. The hard paper itself: http://journals.aps.org/prd/abstract/10.1103/PhysRevD.93.041501

And, text of the story:

Quote

Over the last year, U. Mass Dartmouth physicist Gaurav Khanna and his colleagues have been using a high-powered platform of computers to simulate the interior of a rotating black hole.

Although moviegoers have been treated to a view of the interior maelstrom in the popular film Interstellar, scientists have actually never been able to simulate the inside of a black hole until now.

The good news is that, theoretically, using a black hole as a portal to other points in the universe could be possible.

“This has never been done before,” Khanna told me in an email, “although there has been lots of speculation for decades on what actually happens inside a black hole.”

The problem is challenging. Together with Lior M. Burko, professor at the School of Science and Technology, Georgia Gwinnett College, Lawrenceville, Georgia; and Anil Zenginoglu of the Center for Scientific Computation and Mathematical Modeling, University of Maryland; Khanna developed several new mathematical and computational techniques which they applied with the help of Khanna’s unique Sony Playstation based array of processors.

According to the U. Mass press release:

They used a linear model, which allows them to simulate the early portion of the inner horizon of an old black hole, very much like the black hole shown on Interstellar. For the first time it became possible to see how physical fields blow up on the approach to the singularity. The simulation shows that the singularity is weak, in the sense that while the gravitational tidal forces blow up, they do so fast enough that their interaction with physical objects is still bounded, such that the latter may arrive intact to the singularity.

In essence, Khanna et al have shown that space travel, or more accurately spacetime travel, via black hole could work. Their simulation is certainly consistent with any number of science fiction novels in which black holes are used as portals for the adventurous.

Their paper is just published in Physical Review. [link provided above]

Computer models are, of course, limited by their nature. Khanna’s simulation captures some of the features of the physical system, the early phases of the singularity, but it is by no means a complete rendering.

More complex models need to be tried, he said. And one major challenge, for example, is how the features of the singularity would be modified by quantum gravity, a theory that is still yet to be fully worked out by physicists.

“I expect this to be a new additional area of focus for my research program over the next several years,” said Khanna.

Of course, this still leaves unsolved the problem of how to transport astronauts to the nearest useful black hole. But that’s a problem for engineers….

worktroll · « **Reply #432 on:** 10 February 2016, 22:26:11 »

Quote

while the gravitational tidal forces blow up, they do so fast enough that their interaction with physical objects is still bounded, such that the latter may arrive intact to the singularity.

Those words ... sometimes I hate Science Journalism. That has minimal semantic content. Nor does it say anything about tidal impacts having passed the event horizon, which are a real thing too.

Hawking's sub-title remains valid: "The breakdown of physicists in the vicinity of a naked singularity ..."

Weirdo · « **Reply #433 on:** 10 February 2016, 23:00:24 »

They did that with an array of Playstation knockoffs?

SCIENCE! [rockon]

(Yes, I know. My interpretation is funnier.)

Daryk · « **Reply #434 on:** 11 February 2016, 04:26:45 »

Reading the abstract, I can definitely say "Yep, there's tensor calculus involved there...".

rebs · « **Reply #435 on:** 11 February 2016, 08:57:09 »

Wait a year, and there will be a whole different paper with all knew ideas about what Black Holes are.

That's what I do. ;D

Frabby · « **Reply #436 on:** 12 February 2016, 11:12:45 »

No signal has been received from the Philae probe since 5 July 2015, and today the DLR announced they officially ended the Philae mission because the chances it will ever report back in are almost zero. :(

(This is only for Philae. The Rosetta mission continues.)

Maingunnery · « **Reply #437 on:** 12 February 2016, 12:03:14 »

Quote from: Frabby on 12 February 2016, 11:12:45

No signal has been received from the Philae probe since 5 July 2015, and today the DLR announced they officially ended the Philae mission because the chances it will ever report back in are almost zero. :(

(This is only for Philae. The Rosetta mission continues.)

Philae mission will likely return in the far future as an space archaeology mission. ;)

kato · « **Reply #438 on:** 12 February 2016, 14:45:43 »

Not necessarily so far future. Rosetta will take close-up pictures near the end. Planned resolution of <2 cm from only 1 km away. There's different opinions on whether Rosetta should try to find Philae that way or whether she should opt for more interesting places for that.

rebs · « **Reply #439 on:** 13 February 2016, 00:02:02 »

And we gained lots of painful and fairly expensive experience on the process of anchoring to a low gravity body of difficult to determine consistency. Next mission of similar scope should yield better results.

Failure has many differing grades.

Wrangler · « **Reply #440 on:** 13 February 2016, 14:32:23 »

Not side track the thread, question. In the Honorverse, starships use gravity waves to move through space to hyper space. I know it's fiction, does this discovery have any baring on that?

kato · « **Reply #441 on:** 13 February 2016, 18:41:07 »

Actual gravity waves move at light speed.

kato · « **Reply #442 on:** 08 March 2016, 12:22:01 »

ExoMars should launch in six days btw. 03/14, 09:31 GMT.

Video of planned ExoMars science: https://youtu.be/iUuJqXaCOWw

rebs · « **Reply #443 on:** 08 March 2016, 19:48:10 »

Still crossing my fingers for Europa - with a lander!

ATTEMPT NO LANDINGS THERE.

Not much else to say about that due to rule 4. But then, there's not a lot of good saying it anyway, regardless of rules.

Sabelkatten · « **Reply #444 on:** 09 March 2016, 14:27:38 »

Has ESA tried more than one Mars lander before? Considering how difficult it is to put something safetly down on Mars missing your first try isn't all that strange. Now if we can't manage it the second time it might be time to take a closer look at just who's responsible for those landers... ;)

worktroll · « **Reply #445 on:** 09 March 2016, 16:33:33 »

Quote from: Sabelkatten on 09 March 2016, 14:27:38

Has ESA tried more than one Mars lander before? Considering how difficult it is to put something safetly down on Mars missing your first try isn't all that strange. Now if we can't manage it the second time it might be time to take a closer look at just who's responsible for those landers... ;)

We already know - the Great Galactic Ghoul. Which seems to have a taste for European food, given the failures of ESA & Soviet probes ...

Sabelkatten · « **Reply #446 on:** 09 March 2016, 18:01:27 »

Heh, you'd think the "reds" would be luckier with the "red planet"... ;)

Looking at the article I found a link to the MetNet mission. That looks like a really interesting one for a pretty low budget. Not as flashy as a rover, but actual meteorology could tell us a lot about what happens on Mars. :)

worktroll · « **Reply #447 on:** 09 March 2016, 19:27:20 »

Definitely! I mean, way back when I had to test my Martian climate models against limited obs from two data points (the Viking landers), and was lucky to have even them!

A couple of points on the Tharsis bulge, a couple in the Valley, and one near the bottom of Hellas would be sooo good ... Of course, my preferred method of setting up met stations on the Martian surface involves a team of exologists, a couple of rovers, a trailer full of automated sensor posts, and a dust-proof backhoe ...

ANS Kamas P81 · « **Reply #448 on:** 09 March 2016, 20:12:09 »

Quote from: Sabelkatten on 09 March 2016, 18:01:27

Looking at the article I found a link to the MetNet mission. That looks like a really interesting one for a pretty low budget. Not as flashy as a rover, but actual meteorology could tell us a lot about what happens on Mars. :)

Yeah, but if they don't get their braking and orbits right, they'll have a totally different kind of meteor-ology to study.

kato · « **Reply #449 on:** 10 March 2016, 11:57:10 »

Quote from: Sabelkatten on 09 March 2016, 14:27:38

Has ESA tried more than one Mars lander before?

Technically ESA has never tried a Mars lander. Beagle-2 was a UKSA project that hitched a ride with an ESA probe (similar to how ESA lander Huygens hitched a ride on NASA's Cassini). Financing was 50% UKSA, 50% private.

Quote from: Sabelkatten on 09 March 2016, 18:01:27

Looking at the article I found a link to the MetNet mission. That looks like a really interesting one for a pretty low budget.

Impactors - especially high-precision ones - look great on paper, but they're extremely hard to develop (organizationally) and introduce because the topic branches over quite deeply into military applications, and because the failure rate is pretty steep. ESA for example has consistently rejected proposed impactor missions.