Astronomy & Space Exploration

Has anyone read up on the new research suggesting Dark Energy may not be "all that" ? As in, the Universe is actually expanding at a constant rate, as opposed an an accelerated one as previously thought.
 

Raoul said:
Has anyone read up on the new research suggesting Dark Energy may not be "all that" ? As in, the Universe is actually expanding at a constant rate, as opposed an an accelerated one as previously thought.
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Yep. Not convinced by their statistical findings and suggested conclusion, which is why it's not getting a lot of traction in most mainstream scientific publications. The paper is rather inconclusive in itself (for now), and the whole thing hasn't been peer reviewed just yet (particularly a deeper verification of their statistics, though it's unlikely that the figures are fudged up):
Whether the expansion rate is accelerating or not is a kinematic test and it is only for ease of comparison with previous results that we have chosen to show the impact of doing the correct statistical analysis in the ΛCDM framework. In particular the ‘Milne model’ refers here to an equation of state p = −ρ/3 and should not be taken to mean an empty universe. For example the deceleration due to gravity may be countered by bulk viscosity associated with the formation of structure, resulting in expansion at approximately constant velocity even in an universe containing matter but no dark energy. Such a cosmology is not prima facie in conflict with observations of the angular scale of fluctuations in the cosmic microwave background or of baryonic acoustic oscillations, although this does require further investigation. In any case, both of these are geometric rather than dynamical measures and do not provide compelling direct evidence for a cosmological constant — rather its value is inferred from the assumed ‘cosmic sum rule’: ΩΛ = 1 − Ωm + Ωk. This would be altered if e.g. an additional term due to the ‘back reaction’ of inhomogeneities is included in the Friedmann equations31.

The CODEX experiment on the European Extremely Large Telescope will aim to measure the ‘redshift drift’ over a 10–15 year period to determine whether the expansion rate is really accelerating.
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http://www.nature.com/articles/srep35596

That said, even Perlmutter's Supernova Cosmology Project/Dark Energy hypothesis was an arrow in the dark, and the best of a bunch of obscure suggestions - which is why certain factions of community got behind it - they just had no other explanation for it, so the mysterious Dark Energy concept was easy to employ as Einstein's enigmatic cosmological constant, merely because it made intuitive sense. Most of these things are half baked and get disproven over time - once we gain a greater (yet still incomplete) understanding of the fundamental physical mechanics of the cosmos. Sure hope it's disproven for good, though. The mere thought that we are forever bound to this universe, and the whole fabric is eventually going to ve ripped apart because of the acceleration to >>c is so morbid. Plus, we won't ever be able to trace the big bang because the light will never-ever reach us. :(
 
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http://www.kfdi.com/news/national/twitter-erupts-with-photos-of-largest-supermoon-in-decades
 
http://channel.nationalgeographic.com/mars/

Looking forward to this. First episode available for streaming from the link above.

"
MARS

The year is 2033, and humanity's first crewed mission to Mars is about to become a reality. As a clock counts down the final 90 seconds to landing, an expert crew of astronauts endures the final harrowing moments before touching down on the red planet. Even with the best training and resources available, the maiden crew of the Daedalus spacecraft must push itself to the brink of human capability in order to successfully establish the first sustainable colony on Mars. Set both in the future and in the present day, the global miniseries event MARS blends feature film-caliber scripted elements set in the future with documentary vérité interviews with today’s best and brightest minds in modern science and innovation, illuminating how research and development is creating the space technology that will enable our first attempt at a mission to Mars."
 
Raoul said:
Has anyone read up on the new research suggesting Dark Energy may not be "all that" ? As in, the Universe is actually expanding at a constant rate, as opposed an an accelerated one as previously thought.
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I've only read the media covering it. Would be amazing if the idea of Dark Energy dissolves away. 3 Sigma is still 99% certain though.
 
As a prequel to the MARS series I am watching the BBC series "The Sky at Night". They have one episode on finding life on mars, and one about travel to Proxima B.

Enjoyed both of them.
 
The moon is closer to the Earth tonight than at any time in the last 70 years. I set an reminder about a month ago to remind me.

It just went outside to see if it was up yet and saw:

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Saw it yesterday night when it was a mere smidgen further away, and it looked like a pretty standard Moon. Though the moisture in the air gave it a rainbow halo. Which was nice.
 
I just received a comment on imgur for that photo, saying "I quite like this although it's possibly one of the dullest pictures ever on Imgur +1". I use imgur for literally every picture I've ever put up here and always thought they were private. Some of those are going to look absolutely ridiculous out of context.
 
Raoul said:
Has anyone read up on the new research suggesting Dark Energy may not be "all that" ? As in, the Universe is actually expanding at a constant rate, as opposed an an accelerated one as previously thought.
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Read something about it a month ago or so, but not much. I have a feeling that we really don't know much (if all) for dark matter, let alone for dark energy which is just that fancy term about universe getting rapidly expanding.
 
Mars Ice Deposit Holds as Much Water as Lake Superior
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Frozen beneath a region of cracked and pitted plains on Mars lies about as much water as what's in Lake Superior, largest of the Great Lakes, researchers using NASA's Mars Reconnaissance Orbiter have determined.

Scientists examined part of Mars' Utopia Planitia region, in the mid-northern latitudes, with the orbiter's ground-penetrating Shallow Radar (SHARAD) instrument. Analyses of data from more than 600 overhead passes with the onboard radar instrument reveal a deposit more extensive in area than the state of New Mexico. The deposit ranges in thickness from about 260 feet (80 meters) to about 560 feet (170 meters), with a composition that's 50 to 85 percent water ice, mixed with dust or larger rocky particles.

At the latitude of this deposit -- about halfway from the equator to the pole -- water ice cannot persist on the surface of Mars today. It sublimes into water vapor in the planet's thin, dry atmosphere. The Utopia deposit is shielded from the atmosphere by a soil covering estimated to be about 3 to 33 feet (1 to 10 meters) thick.

"This deposit probably formed as snowfall accumulating into an ice sheet mixed with dust during a period in Mars history when the planet's axis was more tilted than it is today," said Cassie Stuurman of the Institute for Geophysics at the University of Texas, Austin. She is the lead author of a report in the journal Geophysical Research Letters.

Mars today, with an axial tilt of 25 degrees, accumulates large amounts of water ice at the poles. In cycles lasting about 120,000 years, the tilt varies to nearly twice that much, heating the poles and driving ice to middle latitudes. Climate modeling and previous findings of buried, mid-latitude ice indicate that frozen water accumulates away from the poles during high-tilt periods.
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http://www.jpl.nasa.gov/news/news.php?release=2016-299
 
If that blows up on launch... most expensive facepalm of all time.
 
NASA beancounters would probably top themselves.

Going up on an Ariane which hasn't had a failure in over a decade, so should be okay. If not, Trump'll blame Europe and probably disband NATO.
 
RIP John Glenn, first American to orbit the planet, oldest person to visit space, and US senator of 25 years. Not a bad set of achievements to bow out on.

 
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Raoul said:
I would probably cry if that happened.
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When you see this, you realise that one small error could render it completely useless...seeing as its so far away from earth, there's no maintenance or repairs available...

 
Big Andy said:
When you see this, you realise that one small error could render it completely useless...seeing as its so far away from earth, there's no maintenance or repairs available...

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I'm sure over time they would come up with a way to reach it if needed. There's just too much riding on it to allow it to malfunction once without the possibility of repair.
 
New Martian images ft. the Curiosity Rover:

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I'm surprised about that video, I would've expected a vehicle to whirl up some more of the sand/dust or whatever it is (since it leaves a clear trail).

Beautiful pictures though, fascinating to think about the effort it has taken to get them done. Quite the achievement.
 
donkeyfish said:
I'm surprised about that video, I would've expected a vehicle to whirl up some more of the sand/dust or whatever it is (since it leaves a clear trail).

Beautiful pictures though, fascinating to think about the effort it has taken to get them done. Quite the achievement.
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It moves at less than 1mph, not going to be kicking up much dust. Definitely an incredible feat though, hopefully its twin makes it over safely in a few years.
 
Another moonwalker has passed away

 
Crap RIP.

So, 12 people have walked on the moon, 6 have since passed away.

All of the remaining moonwalkers are in the 80's. As heartless as it is to say, it's quite possible that we'll lose all of them before the next person steps on the moon.
 
rcoobc said:
Crap RIP.

So, 12 people have walked on the moon, 6 have since passed away.

All of the remaining moonwalkers are in the 80's. As heartless as it is to say, it's quite possible that we'll lose all of them before the next person steps on the moon.
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Crikey, no wonder they're not sending anyone else up there.
 
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