But hot Earths, which can be up to five times bigger than our Earth, orbit closer to their stars and are not likely to support life. Even if water does contribute to their formation, most hot Earths probably end up dry, study co-author Raymond says.
Among a billion and billion of stars, it is statistically likely to find a planet or two to have just the right condition to hold water at the right temperature. Proof? Look at our planet.
Besides, if Pluto wasn't discovered by Clyde Tombaugh at Lowell Observatory in Arizona (US), I don't think there would have been much strong objection to demote Pluto as a dwarf one.
Still it is a planet, I guess it's a compromise fro the pride.
Photometric uncertainty with the HST/ACS could probably be as high as one percent. There is no way in this kind of astronomy that can determine the percentage good to 0.1%.
I know what you are getting at: you are basically talking about significant figures, which isn't a bad guess. But here I am referring to more traditional statistical errors that should be propagated through analysis.
I just read the actual paper and it doesn't have any good estimate on the error.
If I were known for proving Poincare Conjecture, I wouldn't give a damn to be known as a Fields medal winner. (They'll give it to him anyway, whether he's there personally to receive it.)
Goddard has been undergoing some organizational restructuring over years. That means office shuffling and renovations here and there. It often involves spring cleaning of all the junks piled up on top of shelves and cabinets.
My guess? Some old geezers probably had thrown them away into a garbage bin. It's probably got dumped into some industrial dumping site in New Jersey or somewhere... that said, it's SOL to me.
[I saved one optical disc from a garbage bin once...I'm sure it contains some IUE data, not the moon landing stuff... there is no way to read the damned thing anywhere to be sure...]
It's further complicated by things like the results of the High z supernova search, which suggests the universe is accelerating in its expansion, and so 1/H isn't a good measure of the age of the universe.
We usually talk H(t) (H as a function of time) for that exact reason.
The grand parent's post is really funny, especially after listening to a bunch of atomic/plasma physicists talking about theoretical cross section of some high atomic number species. They would casually say, "the value could be off by a factor of two or three, but it's better than nothing, right?"
It is indeed better than not knowing at all. But they do things the way astronomers do sometimes just as well. Only accurate to an order of magnitude. 1 or Pi, what's the difference?
Having said that, I don't agree with the grand parent's post. But I do say this: astronomers tend to be much more sloppy in their error calculations. I am pretty sure that there are some missing systematic errors creeping into this new Hubble Constant values. For christ's sake, they only use one data sample there!!
How did Laplace determine the existence of the bulge?
Was it a "simple" measurement of the shape of the Moon or something more sophisticated via his favorite mathematic tricks? Considering it is Laplace, he must have measured its eccentricity fairly accurately. I wonder what he used to do that in 1799.
I don't think the Discovery pushed the ISS's orbit higher in this mission, but NASA indeed uses the Shuttle to do that.
We are approaching another Solar minimum. It is a good thing since Earth's atmosphere doesn't puff up too much during the minimum period, hence reducing the level of drag onto the ISS (hence less decay in its orbit).
This was technically the last flight to test the changes made for the CAIB recommendations.
In the next flight, the shuttle program resumes the construction of the ISS (not just delivery of the supplies and take back some garbages). So until the next mission is complete, I wouldn't say that we are back on track with this mission.
It's not easy to crawl into the conduit and locate a leak. Let alone checking what the substance is. (What do you want? Let them lick and taste it to see what it is?)
I'm more bothered by the use of the word "drop" here if you ask me.
My guess is that this experiment is just a higher wavelength laser (think blue vs. red) and appropriate detector.
Bluish green, if I recall correctly. On a slightly misty night I drove by one facility in Greenbelt, Maryland, and saw a freakin' laser beam shooting off the dome. Scare the hell out of me.
"An extraordinary claim requires an extraordinary evidence."
That's what it takes to do science correctly. With some instrument on board a space telescope, the error budget is down to one part in 10,000. Obviously not good enough for this type of research. So they use a ground telescope (much easier to calibrate and stands on the solid ground) to go after "one parts in a million" precision for a project like this.
In short, high precision measurements can be attained with care. And the care must be taken. This isn't an easy business to say the least.
PS. the speed of light is known quite accurately, I believe. Better than one part in million.
Sometimes in astronomy, the handling in errors (both random and systematic) is sloppily done. The random error is probably done ok; but how about systematic ones?
In an attempt to publish hastily, scientists often willingfully ignore some shortcomings in instrumetal calibration, etc., and may not take into account all the uncertainties that should be propagated through their calculations. I hope that those astronomers are not embarrassing themselves by making an error like that.
It's not "fixed". The activation was done using the backup controller (Side 2).
I don't think the engineers know the cause yet. They probably will figure out when the instrument is retrieved from the HST and be brought down to the ground (if that ever happens).
The Hubble's ACS is not repaired; they made the decision that it would not harm the rest of the instrument by activating the backup electronic controller (Side 2).
Historically speaking this marks the half-life time of the mission. It has operated for four years; I expect it to work 3 to 5 more years now.
I don't know if the controllers (Sides 1 and 2) are identical; it wasn't for the STIS and they need to run a series of re-calibration before resuming its science operations. I hope that isn't the case here. I'm supposed to use that camera this month and next.
The satellites which would be severely affected by CMEs are most probably located at geo-synchronous orbit. To bring one closer to Earth, you will have to (1) move it closer to the Earth, and then (2) you also have to slow it down because, as it gets closer to Earth with its angular momentum still conserved (imagine the ice-skater's spinning with and without the arms stretched), the satellite would undergo a faster revolution around the Earth. If you don't slow it down, it'll sling back out to a higher orbit.
Many GPS satellites are orbiting in low-Earth orbits. Those are protected by Earth's magnetic field (most of the time) and will be fine against a regular CME.
Slashdot Mirror
But hot Earths, which can be up to five times bigger than our Earth, orbit closer to their stars and are not likely to support life. Even if water does contribute to their formation, most hot Earths probably end up dry, study co-author Raymond says.
Among a billion and billion of stars, it is statistically likely to find a planet or two to have just the right condition to hold water at the right temperature. Proof? Look at our planet.
An interesting idea, in any case.
No kidding.
Besides, if Pluto wasn't discovered by Clyde Tombaugh at Lowell Observatory in Arizona (US), I don't think there would have been much strong objection to demote Pluto as a dwarf one.
Still it is a planet, I guess it's a compromise fro the pride.
Ooops sorry, it's already in there.
I'd add chemical composition (metallicity, namely), too, to your list.
Photometric uncertainty with the HST/ACS could probably be as high as one percent. There is no way in this kind of astronomy that can determine the percentage good to 0.1%.
I know what you are getting at: you are basically talking about significant figures, which isn't a bad guess. But here I am referring to more traditional statistical errors that should be propagated through analysis.
I just read the actual paper and it doesn't have any good estimate on the error.
Just FYI.
In astronomy, they are indistinguishable.
...Unless newer technology finds dimmer stars, and they have to lower the minimum again.
There may be some truth in this comment. Could it be 8.2% instead?
Whenever you read an article like this, we should pay attention to the error bar. Is it 8.3% +/- 1, 5, or 50%?
If I were known for proving Poincare Conjecture, I wouldn't give a damn to be known as a Fields medal winner. (They'll give it to him anyway, whether he's there personally to receive it.)
Goddard has been undergoing some organizational restructuring over years. That means office shuffling and renovations here and there. It often involves spring cleaning of all the junks piled up on top of shelves and cabinets.
My guess? Some old geezers probably had thrown them away into a garbage bin. It's probably got dumped into some industrial dumping site in New Jersey or somewhere... that said, it's SOL to me.
[I saved one optical disc from a garbage bin once...I'm sure it contains some IUE data, not the moon landing stuff... there is no way to read the damned thing anywhere to be sure...]
It's further complicated by things like the results of the High z supernova search, which suggests the universe is accelerating in its expansion, and so 1/H isn't a good measure of the age of the universe.
We usually talk H(t) (H as a function of time) for that exact reason.
The grand parent's post is really funny, especially after listening to a bunch of atomic/plasma physicists talking about theoretical cross section of some high atomic number species. They would casually say, "the value could be off by a factor of two or three, but it's better than nothing, right?"
It is indeed better than not knowing at all. But they do things the way astronomers do sometimes just as well. Only accurate to an order of magnitude. 1 or Pi, what's the difference?
Having said that, I don't agree with the grand parent's post. But I do say this: astronomers tend to be much more sloppy in their error calculations. I am pretty sure that there are some missing systematic errors creeping into this new Hubble Constant values. For christ's sake, they only use one data sample there!!
How did Laplace determine the existence of the bulge?
Was it a "simple" measurement of the shape of the Moon or something more sophisticated via his favorite mathematic tricks? Considering it is Laplace, he must have measured its eccentricity fairly accurately. I wonder what he used to do that in 1799.
And most importantly... no Miles O'Brien on CSPAN!
I don't think the Discovery pushed the ISS's orbit higher in this mission, but NASA indeed uses the Shuttle to do that.
We are approaching another Solar minimum. It is a good thing since Earth's atmosphere doesn't puff up too much during the minimum period, hence reducing the level of drag onto the ISS (hence less decay in its orbit).
This was technically the last flight to test the changes made for the CAIB recommendations.
In the next flight, the shuttle program resumes the construction of the ISS (not just delivery of the supplies and take back some garbages). So until the next mission is complete, I wouldn't say that we are back on track with this mission.
It's good to have her back safely, nontheless.
It's not easy to crawl into the conduit and locate a leak. Let alone checking what the substance is. (What do you want? Let them lick and taste it to see what it is?)
I'm more bothered by the use of the word "drop" here if you ask me.
My guess is that this experiment is just a higher wavelength laser (think blue vs. red) and appropriate detector.
Bluish green, if I recall correctly. On a slightly misty night I drove by one facility in Greenbelt, Maryland, and saw a freakin' laser beam shooting off the dome. Scare the hell out of me.
Why this is front page news is beyond me.
It may have to do with the submitter.
iforgot /my god, I don't know how many times I saw that password used by my network users...
Yep, that's sort of what I alluded to.
"An extraordinary claim requires an extraordinary evidence."
That's what it takes to do science correctly. With some instrument on board a space telescope, the error budget is down to one part in 10,000. Obviously not good enough for this type of research. So they use a ground telescope (much easier to calibrate and stands on the solid ground) to go after "one parts in a million" precision for a project like this.
In short, high precision measurements can be attained with care. And the care must be taken. This isn't an easy business to say the least.
PS. the speed of light is known quite accurately, I believe. Better than one part in million.
Sometimes in astronomy, the handling in errors (both random and systematic) is sloppily done. The random error is probably done ok; but how about systematic ones?
In an attempt to publish hastily, scientists often willingfully ignore some shortcomings in instrumetal calibration, etc., and may not take into account all the uncertainties that should be propagated through their calculations. I hope that those astronomers are not embarrassing themselves by making an error like that.
It's alive!
It's not "fixed". The activation was done using the backup controller (Side 2).
I don't think the engineers know the cause yet. They probably will figure out when the instrument is retrieved from the HST and be brought down to the ground (if that ever happens).
The Hubble's ACS is not repaired; they made the decision that it would not harm the rest of the instrument by activating the backup electronic controller (Side 2).
Historically speaking this marks the half-life time of the mission. It has operated for four years; I expect it to work 3 to 5 more years now.
I don't know if the controllers (Sides 1 and 2) are identical; it wasn't for the STIS and they need to run a series of re-calibration before resuming its science operations. I hope that isn't the case here. I'm supposed to use that camera this month and next.
pardon me about redundant remarks...shhhh, "to bring it closer, you have to bring it closer...".
That's it. I'm going to sleep.
The satellites which would be severely affected by CMEs are most probably located at geo-synchronous orbit. To bring one closer to Earth, you will have to (1) move it closer to the Earth, and then (2) you also have to slow it down because, as it gets closer to Earth with its angular momentum still conserved (imagine the ice-skater's spinning with and without the arms stretched), the satellite would undergo a faster revolution around the Earth. If you don't slow it down, it'll sling back out to a higher orbit.
Many GPS satellites are orbiting in low-Earth orbits. Those are protected by Earth's magnetic field (most of the time) and will be fine against a regular CME.
That's like launching a nuke into a Category 5 hurricane.
Actually the scale is more like launching a big firework.
No worry, though, Earth's magnetic field is a pretty good shield.