The consensus among professional astronomers is still overwhelmingly in support of the existence of black holes.
Your second point about two neutron stars being unlikely to run into each other is not correct. Extensive studies of binary neutron star systems such as PSR B1913+16 and PSR B1534+12 provide stringent checks on general relativity. Each of these systems has two neutron stars orbiting each other with one of the pair also being detectable as a pulsar. Each component in the system is spiralling in towards the other.
The recent discovery of the first known binary pulsar system (see http://www.atnf.csiro.au/news/press/double_pulsar/) PSR J0737-3039 in 2003-4 using the Parkes radio telescope in Australia provides astronomers with an even better testbed.
In this system the two pulsars orbit each other every 2.4 hours, making them some of the fastest-moving stars known. As they orbit they lose orbital energy through gravitational radiation. They move closer together. The rate at which this happens can be determined and inital studies suggest the two pulsars will coalesce in about 85 million years. This system is about 1,600-2,00 light years or 550 parsecs distant from us. I can assure you that astronomers are actively observing and studying this system as it is allows them to test theories of gravity with incredible precision.
Neutron star collisions do/will occur and will produce strong gravity waves and most likely high fluxes of gamma rays.
There are now long-term projects monitoring pulse arrival times from pulsars across the sky with the aim of detecting gravity waves.
I agree with you re Channel 10 and particularly the ads!! I too will buy the DVD and just bought the miniseries DVD on special last night. Still, given the dearth of good TV around I will continue to tape it on 10 and fast forward through the ads.
Fortunately BSG has just started on free-to-air TV here in Australia (Channel 10). So far just had the opening mini-series and the first normal epsisode. I'm very imrpessed by the dark tone and the interpersonal tensions in the show. Looks promising for the rest of the series. Whilst it obviously borrows thematically from original 70s version it looks like there is a lot more scope for different plot developments here. Also it does not have that annoying robot dog (Moffit, stuffit or whatever its name was)from the original!
The VLBI observations will not be recieving any of the actual data transmissions from Huygens, they are simply measuring the carrier signal and measuring its doppler shift.
The data transmitted by Huygens will be uploaded to the Cassini spaceprobe and then transmitted by Cassini back to Earth several times. This data will be received by the NASA DSN dishes such as that a Tidbinbilla near Canberra in Australia.
Separate to this will be a unique experimental observation organised by JIVE, the Joint Institute for VLBI in Europe that will involve 17 radio telescopes around the world including the Parkes dish in NSW. They will monitor the weak signal of the Huygens probe directly to detct any doppler shift in the signal. Using VLBI (Very Long Baseline Interferometry) astronomers hope to be able to pinpoint the entry of Huygens into Titan's atmosphere to within 1 km. As it descends under parachute they also hope to use doppler shifts to measure the speed of the wind at different levels in the atmosphere. Should be an interesting observation.
(Disclaimer; I work for one of the institutes involved in this experiment)
Driving to work this morning (in Australia) the discussion on the radio was about the half trillion USD current account deficit and the half trillion USD budget deficit. Using my basic maths but woeful understabding of economics this still adds up to a lot of money the US owes. That some high paid US citizens now have their desperately needed tax cuts (after all, new cars are expensive - not to mention Country Club dues) I guess the rest of you will just have to work a bit harder to pay it off.:(
On reading about the missile test failure earlier today I was prompted to go and visit the MDA website http://www.acq.osd.mil/mda/mdalink/html/mdalink.ht ml to see what spin they put on it. Frankly, for the cost of this supposed program one would have expected a better website!
Seriously though you are right to criticise the cost and waste. That our (Australian) government has signed us up to participate in this program makes me even more depressed.
Repeated studies and analysis by the AAS and US physicists shows the futility of most of the current MDA program. Still, somebody is obviously benefitting from it. Downgrading the NSF grants may eventually get rid of those pesky physicists involved in non-defence research so the criticism will go away.
As all Who devotees should know the last series with the Daleks, "Remembrance of the Daleks" finally showed them moving up stairs to get out of a cellar. They used a hover/rocket-type mechanism from my hazy memory. This htus totally wrecked my favourite cartoon from "Punch" magazine.
This had the daleks at the bottom of a set of stairs. The head Dalek said: "Well.. that certainly bu**ers our plans for universal conquest!"
Slashdot Mirror
Actually given what his ego must have been like he was probably pre-Copernican, ie he thought everything revolved around him.
I was hoping to forget it!!
The consensus among professional astronomers is still overwhelmingly in support of the existence of black holes.
/ ) PSR J0737-3039 in 2003-4 using the Parkes radio telescope in Australia provides astronomers with an even better testbed.
Your second point about two neutron stars being unlikely to run into each other is not correct. Extensive studies of binary neutron star systems such as PSR B1913+16 and PSR B1534+12 provide stringent checks on general relativity. Each of these systems has two neutron stars orbiting each other with one of the pair also being detectable as a pulsar. Each component in the system is spiralling in towards the other.
The recent discovery of the first known binary pulsar system (see http://www.atnf.csiro.au/news/press/double_pulsar
In this system the two pulsars orbit each other every 2.4 hours, making them some of the fastest-moving stars known. As they orbit they lose orbital energy through gravitational radiation. They move closer together. The rate at which this happens can be determined and inital studies suggest the two pulsars will coalesce in about 85 million years. This system is about 1,600-2,00 light years or 550 parsecs distant from us. I can assure you that astronomers are actively observing and studying this system as it is allows them to test theories of gravity with incredible precision.
Neutron star collisions do/will occur and will produce strong gravity waves and most likely high fluxes of gamma rays.
There are now long-term projects monitoring pulse arrival times from pulsars across the sky with the aim of detecting gravity waves.
I agree with you re Channel 10 and particularly the ads!! I too will buy the DVD and just bought the miniseries DVD on special last night. Still, given the dearth of good TV around I will continue to tape it on 10 and fast forward through the ads.
Fortunately BSG has just started on free-to-air TV here in Australia (Channel 10). So far just had the opening mini-series and the first normal epsisode. I'm very imrpessed by the dark tone and the interpersonal tensions in the show. Looks promising for the rest of the series. Whilst it obviously borrows thematically from original 70s version it looks like there is a lot more scope for different plot developments here. Also it does not have that annoying robot dog (Moffit, stuffit or whatever its name was)from the original!
The VLBI observations will not be recieving any of the actual data transmissions from Huygens, they are simply measuring the carrier signal and measuring its doppler shift.
The data transmitted by Huygens will be uploaded to the Cassini spaceprobe and then transmitted by Cassini back to Earth several times. This data will be received by the NASA DSN dishes such as that a Tidbinbilla near Canberra in Australia.
Separate to this will be a unique experimental observation organised by JIVE, the Joint Institute for VLBI in Europe that will involve 17 radio telescopes around the world including the Parkes dish in NSW. They will monitor the weak signal of the Huygens probe directly to detct any doppler shift in the signal. Using VLBI (Very Long Baseline Interferometry) astronomers hope to be able to pinpoint the entry of Huygens into Titan's atmosphere to within 1 km. As it descends under parachute they also hope to use doppler shifts to measure the speed of the wind at different levels in the atmosphere. Should be an interesting observation.
(Disclaimer; I work for one of the institutes involved in this experiment)
Not for long though....... Kaboom!!
Driving to work this morning (in Australia) the discussion on the radio was about the half trillion USD current account deficit and the half trillion USD budget deficit. Using my basic maths but woeful understabding of economics this still adds up to a lot of money the US owes. That some high paid US citizens now have their desperately needed tax cuts (after all, new cars are expensive - not to mention Country Club dues) I guess the rest of you will just have to work a bit harder to pay it off. :(
On reading about the missile test failure earlier today I was prompted to go and visit the MDA website http://www.acq.osd.mil/mda/mdalink/html/mdalink.ht ml to see what spin they put on it. Frankly, for the cost of this supposed program one would have expected a better website!
Seriously though you are right to criticise the cost and waste. That our (Australian) government has signed us up to participate in this program makes me even more depressed.
Repeated studies and analysis by the AAS and US physicists shows the futility of most of the current MDA program. Still, somebody is obviously benefitting from it. Downgrading the NSF grants may eventually get rid of those pesky physicists involved in non-defence research so the criticism will go away.
I wish we could specify it ahead of time but are we that lucky?
As all Who devotees should know the last series with the Daleks, "Remembrance of the Daleks" finally showed them moving up stairs to get out of a cellar. They used a hover/rocket-type mechanism from my hazy memory. This htus totally wrecked my favourite cartoon from "Punch" magazine. This had the daleks at the bottom of a set of stairs. The head Dalek said: "Well.. that certainly bu**ers our plans for universal conquest!"