Reply to topic  [ 436 posts ]  Go to page Previous  1 ... 4, 5, 6, 7, 8, 9, 10 ... 18  Next
The Astronomy Thread 
Author Message
User avatar

Joined: Sat Mar 05, 2011 1:35 pm
Posts: 1288
Location: Middle of Nowhere
Post Re: The Astronomy Thread
hi hi

They could undoubtedly reach it with contemporary propulsion (Dawn has ~10km/s of delta v) but it would still take forever. :P


Fri Mar 28, 2014 2:06 pm
Profile WWW
User avatar

Joined: Mon Mar 21, 2011 11:31 am
Posts: 775
Post Re: The Astronomy Thread
icekatze wrote:
They could undoubtedly reach it with contemporary propulsion (Dawn has ~10km/s of delta v) but it would still take forever. :P


Welcome to our "space age". :lol:
Does it matter if it takes a decade, or even half a generation, to arrive? And I say "arrive" on purpose, because flyby missions are a bit of waste IMO. Those just return a snapshot of a continous changing situation.
The benefit of a mission to Chariklo is that a probe going there could have gravity assist from 3 outer planets if necessary and alignments fit (not likely, but I thought I should mention it) the flight trajectory. Or even four if a mission would be launched along Uranus with the purpose of breaking velocity instead of increasing it before continuing to Chariklo.

_________________
Image


Sat Mar 29, 2014 8:50 am
Profile
Site Admin
User avatar

Joined: Fri Mar 04, 2011 9:19 pm
Posts: 3021
Location: San Jose, CA
Post Re: The Astronomy Thread
GeoModder wrote:
icekatze wrote:
They could undoubtedly reach it with contemporary propulsion (Dawn has ~10km/s of delta v) but it would still take forever. :P


Welcome to our "space age". :lol:
Does it matter if it takes a decade, or even half a generation, to arrive? And I say "arrive" on purpose, because flyby missions are a bit of waste IMO. Those just return a snapshot of a continous changing situation.

It would probably take 10-20 years for a Dawn style spacecraft to achieve orbit around Chariklo. 20 years is a lot of time for something to go wrong with the spacecraft; the odds of being fully functional on arrival probably aren't great. It's also probably a challenge to secure funding from politicians who won't be in office (or might not even still be alive) when the thing arrives.

I am excited about New Horizons' flyby of Pluto in July of next year. It is a shame though that after 9.5 years of travel it will only be in the system for about a day. I'm concerned about responding to problems during the encounter when the lightspeed lag to Earth and back will be something like 10 hours.

_________________
Outsider


Sat Mar 29, 2014 12:03 pm
Profile WWW

Joined: Mon Apr 25, 2011 6:04 pm
Posts: 263
Post Re: The Astronomy Thread
I have to question the value of a Chariklo mission when it would be easier and I'd argue more productive to go after Saturn or Jupiter. Sure there is some novelty to it, but the mission would be better served elsewhere. Especially given the constraints on RTG fuel.


Sat Mar 29, 2014 3:49 pm
Profile
User avatar

Joined: Mon Mar 21, 2011 11:31 am
Posts: 775
Post Re: The Astronomy Thread
There's a bit more then novelty to it. It would give (at the moment) unique insight in ring formations of smaller bodies.
While I agree that probes orbiting the jovian planets return more data because the region is more 'crowded' with objects, Saturn and Jupiter each had their share of probes already. So Uranus or Neptune would likely return more new data then a Jupiter/Saturn orbital probe would.
And a mission to land on Europa doesn't really count, it would also be a one-target mission then. :lol:

Arrival time depends largely on fuel mass respective to total probe mass, so if politicians really want their name&fame attached to a deep space mission, they should simply set more money aside for it.
There are probes outthere which already outlived the funding politicians and still return data. And both Galileo and Huygens likely saw the retirement of some of their funders, so I don't think that should be a reason to bar a project.

Personally, I'm more excited about the Dawn probe arriving at Ceres next year. :mrgreen:

_________________
Image


Sun Mar 30, 2014 12:20 pm
Profile

Joined: Thu Jan 30, 2014 12:42 am
Posts: 10
Post Re: The Astronomy Thread
Ceres might be a wetter and much more accessible Enceladus. Anyone know of a reason to send probes to Europa or Enceladus if Ceres turns out to have at least as much of an underground ocean as Enceladus and Europa?


Thu Apr 10, 2014 3:48 pm
Profile
Site Admin
User avatar

Joined: Fri Mar 04, 2011 9:19 pm
Posts: 3021
Location: San Jose, CA
Post Re: The Astronomy Thread
Keter wrote:
Ceres might be a wetter and much more accessible Enceladus. Anyone know of a reason to send probes to Europa or Enceladus if Ceres turns out to have at least as much of an underground ocean as Enceladus and Europa?

That's a big if, but we'll know soon.

_________________
Outsider


Thu Apr 10, 2014 4:39 pm
Profile WWW
User avatar

Joined: Tue Nov 06, 2012 11:10 am
Posts: 60
Location: United Kingdom
Post Re: The Astronomy Thread
I don't have much time these days so I don't think this has already been posted, most I assume would of picked this up already, but for those that haven't.

Saturn might be birthing a new moon...

I'll peg the the BBC article also.

Image


Thu Apr 17, 2014 4:50 am
Profile
User avatar

Joined: Mon Mar 21, 2011 11:31 am
Posts: 775
Post Re: The Astronomy Thread
Yeah, I read it today.
I think it's a stark opinion to say Saturn's rings can't produce a new 'moon' anymore.

_________________
Image


Thu Apr 17, 2014 9:59 am
Profile

Joined: Thu Jul 05, 2012 1:55 pm
Posts: 772
Post Re: The Astronomy Thread
NASA's Kepler Telescope Discovers First Earth-Size Planet in 'Habitable Zone'
Source

_________________
Forum RP: Cydonia Rising
[RP]Cydonia Rising [IC]


Thu Apr 17, 2014 2:47 pm
Profile
User avatar

Joined: Sat Mar 05, 2011 1:35 pm
Posts: 1288
Location: Middle of Nowhere
Post Re: The Astronomy Thread
hi hi

This one is sorta old news, but it seems like NASA is planning on capturing a small asteroid and pulling it into Earth orbit. Which I think is really cool.

Even if we'll probably never build a space elevator, and we won't need it for an anchor, there's still a vast amount of mineral wealth in them asteroids.

(Also, this gives me an excellent opportunity to link this video from Kerbal Space Program. The Kerbal Space Slam!)


Fri Apr 18, 2014 11:20 am
Profile WWW

Joined: Thu Jul 05, 2012 1:55 pm
Posts: 772
Post Re: The Astronomy Thread
NASA's Spitzer and WISE Telescopes Find Close, Cold Neighbor of Sun
Source

_________________
Forum RP: Cydonia Rising
[RP]Cydonia Rising [IC]


Mon Apr 28, 2014 6:23 am
Profile
Site Admin
User avatar

Joined: Fri Mar 04, 2011 9:19 pm
Posts: 3021
Location: San Jose, CA
Post Re: The Astronomy Thread
Yeah, that's two brown dwarf systems within 7 light years. If brown dwarf systems are as common as red dwarfs (as seems likely), or perhaps even more common, then that's an awful lot of mass that's been completely unaccounted for.

_________________
Outsider


Mon Apr 28, 2014 11:36 am
Profile WWW
User avatar

Joined: Mon Mar 21, 2011 11:31 am
Posts: 775
Post Re: The Astronomy Thread
I'm starting to wonder how many rogue planets they'll start discovering in Sol's neighbourhood say in a decade or so.

_________________
Image


Mon Apr 28, 2014 1:22 pm
Profile
Site Admin
User avatar

Joined: Fri Mar 04, 2011 9:19 pm
Posts: 3021
Location: San Jose, CA
Post Re: The Astronomy Thread
GeoModder wrote:
I'm starting to wonder how many rogue planets they'll start discovering in Sol's neighbourhood say in a decade or so.

Actually that's an important element of the recent WISE surveys: the fact that they're able to detect cool brown dwarfs 7 light years away is making it less and less likely that there are still undiscovered large planets poking around the edges of our own system.

_________________
Outsider


Mon Apr 28, 2014 2:49 pm
Profile WWW
Moderator

Joined: Mon Mar 21, 2011 9:02 am
Posts: 980
Post Re: The Astronomy Thread
Arioch wrote:
Yeah, that's two brown dwarf systems within 7 light years. If brown dwarf systems are as common as red dwarfs (as seems likely), or perhaps even more common, then that's an awful lot of mass that's been completely unaccounted for.


Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.


Mon Apr 28, 2014 5:40 pm
Profile
Site Admin
User avatar

Joined: Fri Mar 04, 2011 9:19 pm
Posts: 3021
Location: San Jose, CA
Post Re: The Astronomy Thread
fredgiblet wrote:
Arioch wrote:
Yeah, that's two brown dwarf systems within 7 light years. If brown dwarf systems are as common as red dwarfs (as seems likely), or perhaps even more common, then that's an awful lot of mass that's been completely unaccounted for.


Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.

Yes, that's what I was referring to. I have the feeling that astronomers have grossly underestimated the mass of unseen systems (like brown dwarfs), interstellar gas and dust, and black holes.

_________________
Outsider


Mon Apr 28, 2014 8:25 pm
Profile WWW
User avatar

Joined: Mon Mar 21, 2011 11:31 am
Posts: 775
Post Re: The Astronomy Thread
Arioch wrote:
GeoModder wrote:
I'm starting to wonder how many rogue planets they'll start discovering in Sol's neighbourhood say in a decade or so.

Actually that's an important element of the recent WISE surveys: the fact that they're able to detect cool brown dwarfs 7 light years away is making it less and less likely that there are still undiscovered large planets poking around the edges of our own system.


Oh, I meant with "Sol's neighbourhood" lightyears outthere, not in say the Kuiper -or Oortbelt of our system.
Personally, I don't think the changes of detecting a jovian-mass planet on Sol's outskirts are high. Not with the current record of detecting dwarf planet candidates in the same areas.

_________________
Image


Tue Apr 29, 2014 10:04 am
Profile

Joined: Thu Jan 30, 2014 12:42 am
Posts: 10
Post Re: The Astronomy Thread
I've got a vague memory of recently reading (on ArsTechnica, I think) an article that mentions near-consensus among at least one group of scientists that there's probably something Earth sized or bigger beyond main Kuiper belt but probably not as far as Oort cloud distance. Something about a recent finding making this more likely.


Thu May 08, 2014 9:14 pm
Profile

Joined: Mon Apr 25, 2011 6:04 pm
Posts: 263
Post Re: The Astronomy Thread
fredgiblet wrote:
Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.



Oh I hope so. It would take an awful lot of stuff out there, like implausibly high values of "lots", but oh the schadenfreude. From memory dark matter is supposed to be like 80% of the mass of the universe. Think I said before how dark matter flags my phlogiston filter.


Fri May 09, 2014 6:49 pm
Profile
User avatar

Joined: Fri Mar 02, 2012 6:12 pm
Posts: 283
Post Re: The Astronomy Thread
Nemo wrote:
fredgiblet wrote:
Isn't that what Dark Matter was theorized for? IIRC Relativity wasn't working quite right because things were behaving as if there was a lot more mass than we could see, hence Dark Matter was theorized to fill the gap. An abundance of brown dwarfs could solve that.



Oh I hope so. It would take an awful lot of stuff out there, like implausibly high values of "lots", but oh the schadenfreude. From memory dark matter is supposed to be like 80% of the mass of the universe. Think I said before how dark matter flags my phlogiston filter.


Dark matter represents about 27% of the mass-energy of the universe. It's about 85% of the total amount of matter, though. This is based on the current standard model of cosmology, which is currently the best fitting description we have of the universe.

As to your, and everyone else's, "phlogiston filter" it's interesting how often it gets brought up in this context (along with the aether). Unlike phlogiston, however, dark matter actually has a very strong theoretical underpinning. There are indirect observations of its existence (galactic rotation curves, galactic clusters, large-scale universe structure, artifacts in the CMB, gravitational lensing). Add to the fact that cosmic models that include dark matter are the only ones that get close to producing what we observe the universe to actually be.

Dark matter isn't random. It was proposed to explain observations of stellar motion in the 1930s. Observations since then have only added to its theoretical existence. And, based on our current understanding, it allows us to explain the universe from the Big Bang to now. To date, no modified theory of gravity has been able to produce the same results to the same level of accuracy.

There's a little bit of Occam's Razor involved with dark matter. It's the simplest explanation for what we see. That's not to say it's ultimately right, but that does give it a leg up on the much more complicated modified theories.

I highly recommend the Wikipedia article on Dark Matter. It's actually a very well written synopsis of the current state of the theory and is well-sourced. It includes a discussion and links to alternative theories.


Fri May 09, 2014 8:29 pm
Profile

Joined: Mon Apr 25, 2011 6:04 pm
Posts: 263
Post Re: The Astronomy Thread
I understand the theory and underpinnings, and the alternative theories don't pan out.

Quote:
And, based on our current understanding, it allows us to explain the universe from the Big Bang to now.


This is the part that hangs in the phlogiston filter. Our understanding of things is so complete that when observations don't quite match up there is something wrong with the observation. Yes our understanding of things works well enough for what we do with it and yes non-baryonic matter keeps the current models functioning. Its useful as far as that goes, but in the back of my mind it tingles. There is no (or very little) math to justify that tingle, that doubt. I simply want it to be wrong because I don't want theory to trump contradicting observations.


Sat May 10, 2014 1:27 pm
Profile
User avatar

Joined: Thu Apr 21, 2011 7:11 pm
Posts: 550
Post Re: The Astronomy Thread
I believe this is the closest to a pure technology thread, so I'll just leave this here: http://www.theguardian.com/science/2014 ... -positrons

Next stop, replicators?


Sun May 18, 2014 2:58 pm
Profile
User avatar

Joined: Fri Jan 24, 2014 5:22 pm
Posts: 365
Post Re: The Astronomy Thread
Grayhome wrote:
I believe this is the closest to a pure technology thread, so I'll just leave this here: http://www.theguardian.com/science/2014 ... -positrons

Next stop, replicators?

It said in the article that they aren't on the verge of creating everyday objects.

Scientists can teleport atoms. Doesn't mean they can teleport a person. All this experiment proves is that E=MC^2. That's important, sure, but I'm not sure it has a physical use. Except maybe for providing reaction mass to interstellar spacecraft.

_________________
If every cloud had a silver lining, there would be a lot more plane crashes.


Sun May 18, 2014 3:47 pm
Profile

Joined: Thu Jul 05, 2012 1:55 pm
Posts: 772
Post Re: The Astronomy Thread
Astronomers Find a New Type of Planet: The "Mega-Earth" Link

_________________
Forum RP: Cydonia Rising
[RP]Cydonia Rising [IC]


Mon Jun 02, 2014 1:07 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 436 posts ]  Go to page Previous  1 ... 4, 5, 6, 7, 8, 9, 10 ... 18  Next

Who is online

Users browsing this forum: CaptainChaos and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.