Humanity takes a giant leap backwards... or maybe a step forwards by recognising we're too dependent on outdated, expensive space technology from 40 years ago (more considering Soyuz). The next few years with no US manned launches will be a dull period but in 10 years I think we'll look back and wonder why the shuttle wasn't replaced earlier (or maybe the replacement should have been developed a bit earloer and could have come on line as the shuttle retired).

Still, there's always Virgin Galactic to look forward to!

That's astrology for you.

I don't think the word 'mistake' is harsh...
When Pluto was discovered, we didn't know about the Kuiper Belt - If we had known about it, Pluto would never have been classified 'planet'

An understandable mistake, given the lack of data at the time - but still a mistake.

Sorry but I disagree - it would have been a mistake if we'd known about the Kuiper Belt but designated Pluto a planet none-the-less. What actually happened is the realities of planetary science changed and made the designation of Pluto a 'politcal' issue. Calling Pluto a planet or minor planet or KBO is a subjective issue and IMO has little to do with science. We call anything that orbits a planet a moon no matter it's size, shape, composition or orbit (not quite true - for some reason the Earth has only one Moon despite having other natural objects in orbit). Why is planetary designation different? There seems to some qualative measure required where planets are concerned. The designation for planets were designed specifically to relegate Pluto and prevent the proliferation of planets within the Kuiper Belt region. At the end of the day it's just a label but i personally think it's a shame Pluto had to be 'relegated'. Why not c;lassify bodies by their proximity to the Sun? Inner Planets (Mercury - Mars), Outer Planets (Jupiter - Neptune), Kuiper Belt Planets (Pluto - ?). I guess just object to the term 'minor' as being an unscientific classification.

I also object to the term 'minor - and I do agree that Pluto's relegation was a political decision.

Though I think that the term 'minor' - when referring to 'minor planet' is a fudge, and seemed to come about in order to avoid fully relegating Pluto to the status of 'Trans-neptunian KBO'

There has to be a cut-off point between 'planet' and all the other smaller bodies - or we'd have the situation where the solar-system has thousands, even millions, of 'planets'

Agreed - I thought the general rule of it's spherical and orbits the sun was good enough. The size requirement and orbital eccentricity requirement emloyed to classify Pluto, Eris & Ceres as Minor Planets or even worse Dwarf Planets may well come back and bight those who pushed for the system. We've no idea what lurks out there in the Kuiper belt. There could (most likely are) large bodies with highly eccentric long-period orbits which have avoided detection so far but which when they eventually turn up will force another re-think and make keeping Mercury or even Mars in the 'planet' club a bit tricky.

There's no objective "scientific classification". Humans are doing the classifying, no-one else, and humans can classify them by whatever criteria they decide. And change their minds.

Well that's not true. All three scientific disciplines have very robust scientific classification systems in place that have been used for a long time and managed to survive without people 'changing their minds'.

The whole point is that people within the discipline should have come up with a classification system then applied it to the data. In this case it was the other way round, the scientists who were opposed to Pluto being a planet desinged a classification system specifically to achieve that without expressing a compelling argument as to why. The prospect of having too many planets is not scientific and in the current era of hundreds of exo-planets it's redundant anyway.

Pluto is large enough to be spherical and has moons of it's own. Those two facts make it a planet IMO. Arguing it isn't because it's too far from the sun and has an eccentric, inclined orbit is fine as long as those principals are applied across all known planetary systems but no-one as far as I now has decided what 'too far' form the star is (because it is dependent on the size of the star) or what eccentricity or inclination is allowable for a planet. There are going to be plenty of large planetary bodies discovered within our own solar system and around other stars which by these rules should not be planets but which obviously are.

Landing site chosen for NASA's next Mars Rover.

http://www.jpl.nasa.gov/news/news.cfm?release=2011-222

Pluto'll always be a planet to me. I suspect that the realisation that there could be a lot of Plutos had them worried that planetary status would be somehow diminished, but I happen to think that the more planets the merrier!

Just a heads-up. 1930 BST tonight on CH4 a 90 min prog about the shuttle.

Thanks pmbond, I'll watch that one C4+1 , should be interesting.

thanks for the heads up

This was a controversial by the International Astronomical Union (IAU) back in 2006 and I remember being involved with the debate about this change on Wikipedia at that time.

However, I think they were justified in reassessing their criteria for what a planet is:
1. The object must be in orbit around the Sun.
2. The object must be massive enough to be a sphere by its own gravitational force. More specifically, its own gravity should pull it into a shape of hydrostatic equilibrium.
3. It must have cleared the neighbourhood around its orbit.

Pluto fails as a planet on condition 3 because it's now clear that there's a whole stack of relatively small iceworlds out there beyond Neptune and it would not necessarily have made sense for them all be classified as proper planets. Doing that could have left the solar system with 30 planets, 22 of which were relatively insignificant in size and all bundled together in a belt http://en.wikipedia.org/wiki/File:Ou...abels_comp.png, http://en.wikipedia.org/wiki/File:Th...nians_73AU.svg like a larger asteroid belt. In addition, it's now know that Eris http://en.wikipedia.org/wiki/Eris_%28dwarf_planet%29 is larger than Pluto itself and other equivalent bodies will no doubt be discovered so this IAU decision is rational and does make sense.

That does not mean that these far away bodies are not without interest or that they should not be explored. Indeed, the New Horizons probe http://en.wikipedia.org/wiki/New_Horizons is already on its way to Pluto and it will get there in 2015. Similarly, the asteroids like Vesta and Ceres are worth exploring two as both sets of bodies should reveal more about the early solar system's composition.


Thanks for posting that, tiger2000. There's more here http://www.newscientist.com/article/...d-on-mars.html and here http://www.americanscientist.org/sci...s-landing-site and those sedimentary layers might give some valuable clues about Mars' geological history.

White dwarf stars could have planetary systems with habitable planets

The University of Washington's Eric Agol has proposed http://www.physorg.com/news/2011-03-...te-dwarfs.html that white dwarf stars http://en.wikipedia.org/wiki/White_dwarf could potentially serves as hosts to habitable planets if such planets orbited very closely to dying ember of a white dwarf star. There is also a general news article on this subject here: http://www.world-science.net/otherne...330_whitedwarf

It is an interesting concept and it might indeed be possible since planets have already been discovered orbiting around a pulsar http://en.wikipedia.org/wiki/Pulsar but such worlds there would be inhospitable due to the radiation output of the pulsar.

The current edition of the BBC World Service's Discovery science programme http://www.bbc.co.uk/programmes/p002w557 is about the Nakhla meteorite http://en.wikipedia.org/wiki/Nakhla_meteorite that fell in Egypt a century ago.

Modern analysis has shown that this meteorite originated on Mars and that it is composed of igneous rock http://en.wikipedia.org/wiki/Igneous_rock including the mineral olivine http://en.wikipedia.org/wiki/Olivine. The matter of a future sample return mission to Mars http://mars.jpl.nasa.gov/missions/fu...eMissions.html was discussed and it this type of mission has already been successfully undertaken by the Soviets to get samples of Moon rocks: http://en.wikipedia.org/wiki/Luna_programme

It's a good programme and l recommend it.

Here's a question. Apparently the entire shuttle programme over the 30 years it flew for cost around $250 billion. Was that money well spent? Without the shuttle the HST would most likely never have got off the ground and if it had, it would almost certainly have never been repaired and serviced regularly so it's immense contribution to science would have been lost. Also the ISS would either have never been built or it's design would have been limited by the size constraints of other launchers.

However I personally feel that $250billion could have been far better spent on a natural development of the Apollo technologies which had already prioduced Skylab and Apollo/Soyuz. The US would have had a series of ever larger and more complex Skylabs to rival Mir throughout the 80's and could have developed the Apollo command/service modules for long duration, deep space missions i.e. what NASA is now looking at 30 years later. I've no idea if NASA would have got men to Mars by now but I'm pretty certain they'd have got back to the Moon and would be a lot nearer to a Mars mission than they are currently.

,,,,, would the rocket planes have been even more practical, without Apollo getting in the way?

Budgets & technology were always dictated by politics.

Good point. The X-15 was flying at Mach-7 at 350,000 ft in the early 60's and earned several pilots theior astronaut wings. Perhaps if Von Braun hadn't pursuaded Kennedy that the Moon was the way to go real rocket planes would be filling our skies today?

Meanwhile the lonely astronaut is still stuck on the moon with no hope of rescue.

http://www.youtube.com/watch?v=svAQ6BCIgxg

I'm fairly sure when they started to discover the asteroids at the beginning of the C19th that they just counted them all as full blown planets. They had no reason to think otherwise after all. They had found I think 5 by the time they discovered Neptune in 1846, which made a grand total of 13 planets at that time, and it was only when they started turning up in dozens on photographic plates that a decision was made to give them their own class.

Any of the Pluto'crats' want to campaign for Vesta and the rest (500000 now?) to be restored?

Good point when the apollo program
was cancelled, the next step forward taking cargo into Leo
and returning was the Shuttle. If anyone knows what happens next.

Not sure this has been reported but Pluto has a new moon. See report here

The X-15 programme http://en.wikipedia.org/wiki/X-15 was a success and it could have paved the way for reusable transport into space and hypersonic aircraft, Regrettably, the US abandoned this and the early lifting body technology http://en.wikipedia.org/wiki/Dynasoar in favour of rockets that the Soviets were using to edge ahead of the Americans.

Earth's Trojan asteroid

It appears that the Earth has a Trojan asteroid http://en.wikipedia.org/wiki/Trojan_asteroid which occupies the same orbit as Earth but always stays 60* ahead in the L4 Lagrangian gravitational neutral zone http://en.wikipedia.org/wiki/Lagrangian_point so that there's no chance of a collision.

We subsequently made optical observations which established that 2010 TK7 is a Trojan companion of Earth, librating around the leading Lagrange triangular point, L4. Its orbit is stable over at least ten thousand years.
http://www.nature.com/nature/journal...ATURE-20110728
http://edmonton.ctv.ca/servlet/an/lo...b=EdmontonHome

This Trojan is an ideal candidate for a long-duration, deep-space manned mission in 20 or 30 years time once NASA pull their collective fingure out.

I read or heard a comment somwhere that NASA's saviour in terms of these prestige programs is likely to be China. If The Chinese push ahead with an ambitious manned program including their own space station and Moon missions it will be politically expedient again for the US to invest hugely in NASA to avoid losing out to China in the next space race.

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?