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Edited by Polar Maritime

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Rosetta navigation camera (NAVCAM) image taken on 3 August 2014 at about 300 km from comet 67P/C-G. The Sun is towards the bottom of the image in the depicted orientation.

 

Posted Image

 http://blogs.esa.int/rosetta/2014/08/04/cometwatch-3-august/

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Amazing new pictures now coming in of Rosseta.... That large boulder in middle of the the picture is 125ft Wide.  http://www.esa.int/Our_Activities/Space_Science/Rosetta/Highlights/Postcards_from_Rosetta

 

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Edited by Polar Maritime

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NASA's New Horizons probe is about to cross Neptune's orbit (25th August) and is now less than a year from its closest approach to Pluto on 14th July 2015. Observations are due to begin early next year, with images of superior quality to Hubble's expected within 10 weeks of the closest pass. It feels like yesterday when it first launched in January 2006 and did a flyby of Jupiter in early 2007. Since then the probe has been in deep sleep mode bar occasional scheduled checks and calibrations. I had a bet with myself that it would get to Pluto before Arsenal won another trophy, but last season's FA Cup put paid to that. Posted Image

 

New Horizons is also scheduled to perform observations on other Kuiper Belt objects, and may even be redirected to stage a flyby of one of these mysterious planetoids after the Pluto objective is complete.

 

I'm very fond of this mission. It only just got the go-ahead due to funding issues and given the current cutbacks at NASA will probably be the last such grand project for a long time.

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Can anyone answer what might be an obvious question?  The Sun is a big nuclear reaction. It has shone for billions of years because it is a nuclear reactor and this doesn't use much fuel. However every 5 days on average there is a CME ( Coronal mass ejection). According to Wiki t he average mass is 1.6×1012kg of material ejected. 

 

 How can this be? I wouldn't know how to do the maths but why hasn't the Sun used up all of its mass many millions of years ago?

 

 Brian.

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for those interested in cosmology like myself, here a you tube link for a World Science Fair Multiverse debate featuring eminent theoretical physicists Andrei Linde, Alan Guth, Andreas Albrecht & Neil Turok  ......discussing Chaotic Inflation, string theory, eternal inflation & braneworld cosmology amongst other topics......It's an hour and a half long, but fascinating & worth the long watch all the same......enjoy!  :D

 

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Great find APS - I found it thoroughly absorbing - something I have often wondered about in latter years and believe that there is something in multiverses and if we could ever get to the bottom of this it could help towards answering many of the questions we currently have and no doubt throw up a lot more.

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Can anyone answer what might be an obvious question?  The Sun is a big nuclear reaction. It has shone for billions of years because it is a nuclear reactor and this doesn't use much fuel. However every 5 days on average there is a CME ( Coronal mass ejection). According to Wiki t he average mass is 1.6×1012kg of material ejected. 

 

 How can this be? I wouldn't know how to do the maths but why hasn't the Sun used up all of its mass many millions of years ago?

 

 Brian.

Sorry Benny, haven't been on for a while.

 

Saw your question, I think my maths is right here,

 

The sun ( according to Wiki ) currently has a mass of approx 2X1030 if you take into account every CME (occuring at a rate of one every 5 days) throwing out 1.6X1012, that has, to date, only thrown out

0.00000000000000000000000000001% (that's 29X0) of the mass of the sun.  It's a big so and so, but, for us at least just the right size to burn for another 4.5 billion years

 

Also add back the fact that altough a substantial mass is ejected, the majority of it doesn't leave the solar system and much is recaptured by the sun.

 

So we're OK for a while yet

Edited by NorthNorfolkWeather

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By observing four galaxies colliding simultaneously, a group of researchers from six countries, including Switzerland, revealed on Wednesday that for the first time, they had found dark matter interacting with itself through a force other than gravity.

 

http://www.swissinfo.ch/eng/scientific-partnerships_researchers-map-and-unlock-new-secrets-of-dark-matter/41381226

Edited by Polar Maritime

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Scientists have revealed a galaxy five billion light-years away, using a new hi-tech telescope in remote Western Australia.

 

http://www.csiro.au/en/News/News-releases/2015/Weve-revealed-a-galaxy-far-far-away?featured=F29EDEB1728C4A92B579C7A5DC28BAD5

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Turn quality up to 4K. 

 

Edited by Polar Maritime

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Hi, I saw a spectacular green fireball last night. About 1.29am to the west of Hebden Bridge. I thought it was a firework at first it was so bright in the night sky. Lasted a few seconds before fading. I went on twitter and found several other people who saw it from as far apart as Manchester, Warrington and Belfast. Also got reports of sightings around the same time from Argentina and the US but I imagine they were seperate incidents. NASA had said there was a very large asteroid passing earth yesterday so one has to wonder if smaller 'lumps' travel along with these big ones. It was the most amazing celestial experience of my life! Anyone else see it?

Edited by Cumulonimbus Tower

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Geminids meteor shower peaks over the next 2 nights.

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2 hours ago, Polar Maritime said:

Geminids meteor shower peaks over the next 2 nights.

It's a fine shame that it has been cloudy down here, I had my tripod & phone at the ready. :(

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Wow,  British man Tim Peake reaches space and is on his way to the ISS for

a 6 month stay.  (No separate thread for this ?)

Yikes it is both very scary and awesome to watch the Russian rocket launch.

Loved Tim's thumbs up as he headed for space.  Good luck to all the crew.

B.  :)

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Edited by Polar Maritime

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ON THE FORMATION OF SUPER-EARTHS WITH IMPLICATIONS FOR THE SOLAR SYSTEM Rebecca G. Martin and Mario Livio Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA Draft version March 29, 2016 ABSTRACT;

We first consider how the level of turbulence in a protoplanetary disk affects the formation locations for the observed close–in super–Earths in exosolar systems. We find that a protoplanetary disk that includes a dead zone (a region of low turbulence) has substantially more material in the inner parts of the disk, possibly allowing for in situ formation. For the dead zone to last the entire lifetime of the disk requires the active layer surface density to be sufficiently small, Σcrit . 100 g cm−2 . Migration through a dead zone may be very slow and thus super–Earth formation followed by migration towards the star through the dead zone is less likely. For fully turbulent disks, there is not enough material for in situ formation. However, in this case, super–Earths can form farther out in the disk and migrate inwards on a reasonable timescale. We suggest that both of these formation mechanisms operate in different planetary systems. This can help to explain the observed large range in densities of super–Earths because the formation location determines the composition. Furthermore, we speculate that super–Earths could have formed in the inner parts of our solar system and cleared the material in the region inside of Mercury’s orbit. The super–Earths could migrate through the gas disk and fall into the Sun if the disk was sufficiently cool during the final gas disk accretion process. While it is definitely possible to meet all of these requirements, we don’t expect them to occur in all systems, which may explain why the solar system is somewhat special in its lack of super–Earths.

http://arxiv.org/pdf/1603.08145v1.pdf

 

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