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Space and Astronomy Thread |
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#1776 |
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Join Date: May 2004
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Quote:
Point 3 is a complete sham in my view. What does it mean? There's a hell of a lot of 'debris' orbiting around the inner solar system so you could easily argue that none of the inner planets are planets by that criteria. How for does a candidate planet's orbit extend? What constitutes it's neighbourhood? What constututes clearing?
If Ceres http://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29 had been the only celestial body between Mars and Jupiter and had Pluto been the only world beyond Neptune then they might well deserve the term planet but that isn't the case. Indeed, Pluto's actually smaller than Eris http://en.wikipedia.org/wiki/Eris_%28dwarf_planet%29 and my money is on more equally large, or even larger, bodies being out there. More here: http://en.wikipedia.org/wiki/IAU_definition_of_planet |
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#1777 |
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Join Date: Jul 2011
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I have a question for the astronomers.
Can the southern constellations be viewed from West Africa but north of the equator, can say Crux be seen from Senegal or The Gambia, if it can is it only certain months? |
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#1778 |
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Join Date: Jun 2006
Posts: 19,567
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Quote:
I have a question for the astronomers.
Can the southern constellations be viewed from West Africa but north of the equator, can say Crux be seen from Senegal or The Gambia, if it can is it only certain months? Then as the months go round you see different constellations just like you do from Britain. Crux is at 60 degrees south so it would begin to be seen from north Africa from about the Tropic of Cancer. Apparently May is the best month to see Crux. |
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#1779 |
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Join Date: Nov 2004
Location: Solihull
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Quote:
lt should not be one of a number of similar bodies orbiting in the same broad orbital band which would cover the asteroids and ice asteroids (Kuiper Belt Objects)
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#1780 |
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Join Date: May 2004
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Quote:
Good reply except it still doesn't clear the important point, that being the definition of, as you put it, a broad orbital band. I totally accept the astreroid belt as a defined region and therefore the larger bodies within it i.e. Ceres, just being large asteroids. However the KB is far, far more extensive and I think it's pushing it to call every body, no matter what it's size or mass, a 'minor' planet. In fact as there is no clear definition (as far as i know) of how far the KB extends I think it's clearly a unscientific definition to claim that Pluto or Eris have not 'cleared;' their orbits when it's not been specifically decided how far their orbits or rather their orbital neighbourhoods extend radially, or what 'clearing;' the orbit means. How large does a body need to be in proportion to the candidate planet for that planet to have not 'cleared' the body?
It is clear from statistical analyses of the known orbital paths of these far away little worlds that there are two distinct bands within the Kuiper Belt and this is illustrated in these two diagrams here: http://en.wikipedia.org/wiki/File:Se...gramofkbos.svg http://en.wikipedia.org/wiki/File:Th...t_75AU_All.svg The implications are that the great majority of outer Kuiper Belt objects do not follow clear, unique orbits in their own right, like Earth and Mars do, but that they orbit in defined bands with similar objects just as the asteroids do. In one sense it would have been easier if these worlds hadn't been discovered as it messes things up. Indeed, Eris http://en.wikipedia.org/wiki/Eris_%28dwarf_planet%29 itself is named after the goddess of discord which sums up the whole situation! To not do anything could have meant that a whole bunch of little, outer ice worlds would have gained full planetary status http://en.wikipedia.org/wiki/File:EightTNOs.png and so a majority of the Solar System would then have comprised of far away and insignificant ice worlds. "It is suspected that at least another forty known objects in the Solar System are dwarf planets, and estimates are that up to 200 dwarf planets may be found when the entire region known as the Kuiper belt is explored, and that the number might be as high as 2,000 when objects scattered outside the Kuiper belt are considered." http://en.wikipedia.org/wiki/Dwarf_planet The International Astronomical Union has probably made the best job it could have done under the circumstances and its criteria are at least rational and not wholly arbitrary such as a 1000km diameter limit on the definition of a planet (which would exclude Ceres http://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29). If you really want to take the matter further, Assa2, you're going to have to take it up directly with the International Astronomical Union who made this decision in the first place: http://www.iau.org/administration/secretariat/ |
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#1781 |
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Join Date: Apr 2005
Location: Crawley, West Sussex
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Incoming CME
Apparently there is a strong Coronal Mass Ejection due to arrive from the Sun sometime in the next 24 hours, which could produce aurora.
Keep an eye on this, and if it gets up to a value of 7 during hours of darkness, and you are in the northern parts of the UK have a look out. If it should get to 9, then anywhere in the country is possible. See here for more details. |
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#1782 |
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Join Date: Apr 2009
Location: london
Posts: 307
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On a different note, here's some flowing liquid on mars?!
http://www.bbc.co.uk/news/science-environment-14408928 |
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#1783 |
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Join Date: Nov 2004
Location: Solihull
Posts: 7,274
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Quote:
I have to differ there, Assa2. There are an estimated 70,000 Kuiper Belt objects over 100km in diameter and I suspect that might be an underestimate as newer, bigger telescopes will probably discover more of these ice worlds.
It is clear from statistical analyses of the known orbital paths of these far away little worlds that there are two distinct bands within the Kuiper Belt and this is illustrated in these two diagrams here: http://en.wikipedia.org/wiki/File:Se...gramofkbos.svg http://en.wikipedia.org/wiki/File:Th...t_75AU_All.svg The implications are that the great majority of outer Kuiper Belt objects do not follow clear, unique orbits in their own right, like Earth and Mars do, but that they orbit in defined bands with similar objects just as the asteroids do. In one sense it would have been easier if these worlds hadn't been discovered as it messes things up. Indeed, Eris http://en.wikipedia.org/wiki/Eris_%28dwarf_planet%29 itself is named after the goddess of discord which sums up the whole situation! To not do anything could have meant that a whole bunch of little, outer ice worlds would have gained full planetary status http://en.wikipedia.org/wiki/File:EightTNOs.png and so a majority of the Solar System would then have comprised of far away and insignificant ice worlds. "It is suspected that at least another forty known objects in the Solar System are dwarf planets, and estimates are that up to 200 dwarf planets may be found when the entire region known as the Kuiper belt is explored, and that the number might be as high as 2,000 when objects scattered outside the Kuiper belt are considered." http://en.wikipedia.org/wiki/Dwarf_planet The International Astronomical Union has probably made the best job it could have done under the circumstances and its criteria are at least rational and not wholly arbitrary such as a 1000km diameter limit on the definition of a planet (which would exclude Ceres http://en.wikipedia.org/wiki/Ceres_%28dwarf_planet%29). If you really want to take the matter further, Assa2, you're going to have to take it up directly with the International Astronomical Union who made this decision in the first place: http://www.iau.org/administration/secretariat/ |
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#1784 |
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Join Date: Nov 2004
Location: Solihull
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On a different note, here's some flowing liquid on mars?!
http://www.bbc.co.uk/news/science-environment-14408928 Is it worth $1billion to mount an all-out assualt on Mars with a new generation of landers to confirm life is there (which is more-or-less what is happening now) or would it be better to spend $10billion over the next 10 years to develope and launch some more ambitious probes to Europa and other outer solar system candidates to try and find life that is clearly seperate from Earth/Mars? |
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#1785 |
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Join Date: Jul 2003
Location: Kent
Posts: 9,781
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Juno probe should be taking off soon hopefully (holding at T-Minus 4 minutes at the moment):
http://missionjuno.swri.edu/Launch or http://www.nasa.gov/multimedia/nasatv/ NASA stream is a couple of minutes behind the swri one (for me anyway). |
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#1786 |
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Join Date: Jul 2003
Location: Kent
Posts: 9,781
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New launch time: 17:25
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#1787 |
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Join Date: Jul 2003
Location: Kent
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Good stuff - congrats to the Juno (and Atlas) teams.
Just got to wait 5 years for the data so start rolling in now!! |
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#1788 |
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Join Date: Apr 2005
Location: Crawley, West Sussex
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Quote:
Apparently there is a strong Coronal Mass Ejection due to arrive from the Sun sometime in the next 24 hours, which could produce aurora.
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#1789 |
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Join Date: Dec 2005
Location: London
Posts: 499
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Quote:
Is it worth $1billion to mount an all-out assualt on Mars with a new generation of landers to confirm life is there (which is more-or-less what is happening now) or would it be better to spend $10billion over the next 10 years to develope and launch some more ambitious probes to Europa and other outer solar system candidates to try and find life that is clearly seperate from Earth/Mars?
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#1790 |
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Forum Member
Join Date: Apr 2005
Location: Crawley, West Sussex
Posts: 9,299
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Quote:
Apparently there is a strong Coronal Mass Ejection due to arrive from the Sun sometime in the next 24 hours, which could produce aurora.
Keep an eye on this, and if it gets up to a value of 7 during hours of darkness, and you are in the northern parts of the UK have a look out. If it should get to 9, then anywhere in the country is possible. See here for more details. |
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#1791 |
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Join Date: Nov 2004
Location: Solihull
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Quote:
As far as I know the Europa Jupiter System Mission is in the planning stage and due to be launched in 2020, arriving 2025. This will send a probe into Europa's oceans and hopefully we'll see little things swimming about, can't wait.
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#1792 |
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Join Date: May 2004
Location: Storbritannia
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Quote:
On a different note, here's some flowing liquid on mars?!
http://www.bbc.co.uk/news/science-environment-14408928 Quote:
The fact that it requires briney water to allow this sort of mud-slide to occurr is very interesting. I suspect it's not going to be too long before we get confirmation of micro-organisms alive and well on Mars. However I think they'll be very closely related to Earth-bound microbes. There's enough material swapped between Mars and Earth for the two ecosystems to not be considered completely seperate.
Is it worth $1billion to mount an all-out assualt on Mars with a new generation of landers to confirm life is there (which is more-or-less what is happening now) or would it be better to spend $10billion over the next 10 years to develope and launch some more ambitious probes to Europa and other outer solar system candidates to try and find life that is clearly seperate from Earth/Mars? http://www.nasa.gov/mission_pages/MR...o20110804.html http://www.nasa.gov/mission_pages/MR.../pia14472.html Static images such as these have been noticed for over a decade now and this is the best indication yet that it's some form of aqueous saline solution that's responsible and not other causes such as liquid carbon dioxide or mixed flows of cardon dioxide gas and martian dust like a pyroclastic flow on Earth. This find prompted an article in the Independent about the enduring fascination with Mars: http://www.independent.co.uk/news/sc...t-2332677.html "Life may not automatically follow from the discovery of flowing water on Mars, but it certainly brings the prospect closer. And the discovery of life on another planet, no matter how primitive and microbial, would certainly amount to one of the greatest scientific finds of all time." Whilst I like the tone of that article, I think it would be mistaken to concentrate on finding life as the sole objective of future robotic missions to Mars since life is clearly not widespread or abundant today. It would seem far better to concentrate on the geology and history of the planet and on the inventories of volatile subsstances such as carbon dioxide, water, nitrogen, etc. and that in turn will inform the debate about life. In particular, further research should help to clear up whether Mars had an extended phase as a warm, wet world in its early history or whether it's always been cold and dry put punctuated by the occasional cataclysmic events such as large meterorite strikes or huge volcanic eruptions that resulted in brief warm periods. Regrettably, things are not looking good in the long term for funding though. The agreement reached last week on raising the debt ceiling has also paved the way for massive spending cuts in the longer term plus the House of Representatives is now dominated by a bunch of anti-science Republican morons. Things got so bad last year that the world's foremost science magazine, Nature, issued a broadside against them: "The anti-science strain pervading the right wing in the United States is the last thing the country needs in a time of economic challenge." http://www.nature.com/nature/journal...l/467133a.html That means funding for space exploration of all kinds is going to get harder and there will be no human return to the Moon or going to Mars within the next couple of decades. Perhaps the best we can hope for is a sample return mission to Mars like some of the Soviet Luna missions to the Moon: http://en.wikipedia.org/wiki/Luna_16 http://en.wikipedia.org/wiki/Luna_20 http://en.wikipedia.org/wiki/Luna_24 |
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#1793 |
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Forum Member
Join Date: May 2004
Location: Storbritannia
Posts: 28,927
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News Round Up...
Earth may once have had two moons
A new theory suggests the Earth once had a small second moon that perished in a slow motion collision with its "big sister". http://www.bbc.co.uk/news/science-environment-14391929 This is one explanation why the hidden far side of the Moon http://en.wikipedia.org/wiki/Far_side_of_the_Moon might be thicker and more massive when compared to the Earth-facing side. Multiverse theory suggested by cosmic microwave background The idea that other universes - as well as our own - lie within "bubbles" of space and time has received a boost. Studies of the low-temperature glow left from the Big Bang suggest that several of these "bubble universes" may have left marks on our own. http://www.bbc.co.uk/news/science-environment-14372387 The interesting thing about this report is that co-existent multiple universes are not incompatible with string theory http://en.wikipedia.org/wiki/String_theory. Radio telescope to be larger than the Earth A Russian space telescope conceived during the Cold War is set to launch on Monday. When it reaches an orbit that will extend almost as far as the moon, the RadioAstron mission will sync up with radio antennas on the ground, effectively forming the biggest telescope yet built, with a "dish" spanning almost 30 times the Earth's diameter. http://www.newscientist.com/article/...han-earth.html This is similar to the MERLIN telescope array concept http://en.wikipedia.org/wiki/MERLIN albeit on a much larger scale. Russian Soyuz to launch from Arianespace's French Guiana site in autumn 2011 These tests will give the green light for the first Soyuz flight from French Guiana in the third quarter of 2011. http://www.esa.int/esaCP/SEMYBDZ57NG_index_0.html http://www.russianspaceweb.com/kourou_els.html http://www.arianespace.com/launch-se...t-brochure.asp http://www.arianespace.com/news-soyu...yuz_update.asp http://multimedia.esa.int/Videos/201.../%28lang%29/en The Soyuz launcher will be a medium lift vehicle option to complement Ariane 5 (heavy lift) and Vega (light payloads). This also means that human crews could theoretically be launched into space on board Soyuz capsules at some future stage as well. |
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#1794 |
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Forum Member
Join Date: Nov 2004
Location: Solihull
Posts: 7,274
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Here's a link to the wierdest and strangely disturbing bit of scientific news I've come across recently.
http://gizmodo.com/5131839/physicist...ted-the-pixels Basically, if I understand it correctly, a detector in Germany built to observe gravity waves has found signs of pixilation or granularity (or something) in the fabric of space-time which could be a result of the universe being nothing more than a hologram. I originally read the New Scientist article which the link links to and which is much clearer than my poor attempt at a simple explanation. Despite it being a load of rubbish I'm sure, it is one of those articles that led me to some quite uncomfortable contemplations for a few minutes. |
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#1795 |
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Join Date: Nov 2004
Location: Solihull
Posts: 7,274
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"US military loses contact with hypersonic aircraft"
http://www.bbc.co.uk/news/world-us-canada-14497641 Second launch - second failure (although the first was deemed a qualified success). Keep at it, lads! |
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#1796 |
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Forum Member
Join Date: Jan 2003
Location: Marineville
Posts: 373
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Quote:
"US military loses contact with hypersonic aircraft"
http://www.bbc.co.uk/news/world-us-canada-14497641 Second launch - second failure (although the first was deemed a qualified success). Keep at it, lads! Just a theory, I think it hit the correct speed (10,088 mph perhaps) ignited the flux capacitor thus hurtling the plane through a time warp. Somewhere, sometime a grey haired scientist is examining the wreckage and will use it to go back to the future, possibly 1955, and invent rock and roll... |
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#1797 |
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Join Date: Jan 2004
Location: 51°30'4.56"N 0° 8'31.21"W
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Perseids shower tonight, skies are really clear here in south oxon, but there is an almost full moon, which will unfortunatly mean only the brightest shooting stars will be seen.
http://www.bbc.co.uk/news/science-environment-14503284 |
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#1798 |
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Forum Member
Join Date: May 2003
Location: The Green Hills of Earth
Posts: 80,438
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The search continues: http://cosmiclog.msnbc.msn.com/_news...ive-seti-quest Quote:
The SETI Institute's search for extraterrestrial intelligence is back on track, thanks to more than $200,000 in donations from thousands of fans. In April, the institute had to put its big ear for hearing E.T.'s radio call, the 42-antenna Allen Telescope Array in Northern California, into "hibernation" due to budget woes. The biggest hit was the loss of funding by the University of California at Berkeley, the institute's partner for operating the antenna array. The SETI Institute has been around for decades: It stepped in to help keep the search for alien radio signals active after NASA cut off funding for the quest in 1993. Congratulations to all who contributed. |
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#1799 |
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Forum Member
Join Date: Mar 2007
Location: Newcastle Upon Tyne
Posts: 53,213
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Hi all
On the 5th i saw Aurora and on the 13th and 14th i saw Parseids and the ISS tonight i will be looking for the ISS as it passes |
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#1800 |
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Forum Member
Join Date: May 2004
Location: Storbritannia
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Quote:
Hi all
On the 5th i saw Aurora and on the 13th and 14th i saw Perseids and the ISS tonight i will be looking for the ISS as it passes .And now for some astro news... Darkest exoplanet spotted by astronomers A dark alien world, blacker than coal, has been spotted by astronomers. http://www.bbc.co.uk/news/science-environment-14476411 Mars rover Opportunity now at vast Endeavour crater At the crater, Opportunity will travel south across the rim to perform a geological assessment of the location, examining the clay minerals formed under wet conditions at the oldest of the four craters it has visited. http://www.independent.co.uk/news/sc...d-2334921.html |
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