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Astronomers Find Star Orbiting a Black Hole At 1 Percent the Speed of Light (sciencealert.com)
schwit1 writes: Astronomers have spotted a star whizzing around a vast black hole at about 2.5 times the distance between Earth and the Moon, and it takes only half an hour to complete one orbit. To put that into perspective, it takes roughly 28 days for our Moon to do a single lap around our relatively tiny planet at speeds of 3,683 km(2,288 miles) per hour. Using data from an array of deep space telescopes, a team of astronomers have measured the X-rays pouring from a binary star system called 47 Tuc X9, which sits in a cluster of stars about 14,800 light-years away. The pair of stars aren't new to astronomers -- they were identified as a binary system way back in 1989 -- but it's now finally becoming clear what's actually going on here. When a white dwarf pulls material from another star, the system is described as a cataclysmic variable star. But back in 2015, one of the objects was found to be a black hole, throwing that hypothesis into serious doubt. Data from Chandra has confirmed large amounts of oxygen in the pair's neighborhood, which is commonly associated with white dwarf stars. But instead of a white dwarf ripping apart another star, it now seems to be a black hole stripping the gases from a white dwarf. The real exciting news, however, is regular changes in the X-rays' intensity suggest this white dwarf takes just 28 minutes to complete an orbit, making it the current champion of cataclysmic dirty dancers. To put it in perspective, the distance between the two objects in X9 is about 1 million kilometers (about 600,000 miles), or about 2.5 times the distance from here to the Moon. Crunching the numbers, that's a journey of roughly 6.3 million kilometers (about 4 million miles) in half an hour, giving us a speed of 12,600,000 km/hr (8,000,000 miles/hr) - about 1 percent of the speed of light.
I have a simple question. How does this affect anyone? Can anyone explain how a distant black hole and star that humans will never visit, affects anyone at all? Why are tax dollars funding useless research like this when the money could fund our military or cutting taxes on our businesses. This research is even more wasteful than the EPA, and useless work like this is exactly what's wrong with America. The academics sit in their ivory tower and do worthless research like this while blue collar workers are put out of jobs. Can anyone explain to me how this affects normal people like me? I think not, but I expect I'll be censored by the moderators so they can avoid answering the tough questions.
ask this question "Why are tax dollars funding useless research like this when the money could fund our military or cutting taxes on our businesses." Seems this time Slashdot is the location of this black hole.
by TheSpoom (715771) Uncaring Linux user here. I have nothing to add to this but please continue. *munches popcorn*
I must say that was my exact reaction to reading it, whoever wrote that really needs to get some perspective, perhaps a nice car analogy.
Km and miles are useless in visualizing this. Please tell me how many schools buses lined up end-to-end will cover the distance between them.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
With the tidal forces this star has to be shaped like a big bent line whipping through space. I imagine pretty massive to keep a elongated core at critical mass as it whips around this star. It might be able to turn even a red giant into a super long white dwarf by stretching out the layers and surface area.
I must say that was my exact reaction to reading it, whoever wrote that really needs to get some perspective
“Have some sense of proportion!” she would say, sometimes as often as thirty-eight times in a single day.
And so he built the Total Perspective Vortex — just to show her.
To Trin Tragula’s horror, the shock completely annihilated her brain; but to his satisfaction he realized that he had proved conclusively that if life is going to exist in a Universe of this size, then the one thing it cannot afford to have is a sense of proportion."
Douglas Adams - The Restaurant at the end of the Universe
"She's furniture with a pulse"
Ok, I'll bite.
Most of tax money spent by your government will never benefit you directly. By "most" i really mean ALL of it, except tiny, tiny fractions of a percent.
This includes roads you'll never drive on, parks you'll never visit, government building you'll never step foot into, hospitals you'll never get treated at, employees you'll never need, etc., etc.
But getting back to the issue at hand, if you care looking at the linked documents from TFS, you'll see the contributors' universities:
1 Department of Physics, CCIS 4-183, University of Alberta, Edmonton, AB T6G 2E1, Canada
2 Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA
3 International Centre for Radio Astronomy Research - Curtin University, GPO Box U1987, Perth, WA 6845, Australia
4 Columbia Astrophysics Laboratory, Columbia University, New York, NY, USA
5 Department of Physics, Texas Tech University, Lubbock, TX, USA
6 School of Physics and Astronomy, University of Southampton, Southampton, UK
7 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
8 NASA Goddard Space Flight Center, Greenbelt, MD, USA
#1, #3 and #6 are not USA-based.
#2, #4, #5 and #7 are universities which are most likely privately funded.
That leaves #8 as the only gov't funded location.
I'd say your tax money are pretty safe from this and would very likely be spent on genuinely useless endeavors which would never be of help to anyone.
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
To put that into perspective, it takes roughly 20 furlongs for our Walmart Goodyear Valvoline Ford to do a single lap around our relatively tiny raceway at speeds of 4,828 m (15,840 feet) per minute.
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
I'm wondering about how quickly such a system loses energy. In general relativity, not even Keplerian orbits should be stable.
Ezekiel 23:20
I wonder, how long it will take for the star to fall into the black hole? Or it will completely evaporate sooner? And how the orbit looks like?
If you post as an AC, don't expect me to spend a mod point on you.
I don't pay tax. The little people pay tax. So maybe it does affect you only?
Rather spend my tax money on this than building fighter jets that can't fly in the rain.
Only crack the nuts that crack. You don't put the ones that don't crack in the sack.
Agreed!
A better way to put that into perspective would be to mention that that Moon's orbital path is 2,412,517.5 km (or 1,499,070 miles) and that if it were orbiting the Earth at the same speed as this star, it would orbit every 11.5 minutes (2,412,517.5 km / 12,600,000 km/hr), or 5 times an hour.
Oh, please. It's wonderful that you are able to understand this so intuitively. But who gives a shit if an accessible description is provided for less technically-minded people?
And, if you really want to go there, it should be presented in m/s anyway.
I must say that was my exact reaction to reading it, whoever wrote that really needs to get some perspective, perhaps a nice car analogy.
Perspective?
We still shove hundreds of horses under a car hood to measure it's power, and we love to get hopes up when discussing habitable planets that are "only" a few light years away, while describing an object traveling 8 million miles per hour using a metric invented in the 18th century.
Hope that helps.
Heh, Ganymede is about 1 million km from Jupiter, and it takes 7 days to complete its orbit. For the black hole, it is half an hour. IO takes 1.8 days to orbit Jupiter, and it is about as far away as earth's moon. Earth's moon takes about 28 days to orbit Earth. Makes this earthling feel small.
Here in the UK, our press uses the following units of measurement:
Distance: buses parked end-to-end.
Weight: elephants.
Area: Wales.
Please amend the article appropriately.
Astronomers have spotted a star whizzing around a vast black hole
Black holes are the antithesis of vast. They have no size whatsoever.
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From the orbit radius and period we can work out the mass of the black hole is 1.8E+32 kg, or about 90 solar masses. Hence it's Swartzchild radius is roughly 300 km.
The Roche limit for this body depends on the density of the satellite, e.g. for a planet like Earth it'd be 2.5 million km and we'd be so much space jam before we ever got as close.
Fortunately white dwarf stars are pretty compact (approx 1 billion kg/m3), so their Roche limit is a snug 44,000 km.
Must be a hell of a view!
Assuming you're American - it wasn't, since this research was done by Australian scientists.
Unicode killed the ASCII-art *
How long does it take your boat to go around the harbor?
Knot furlong?
Sadly for you, I live in a different country, on a different continent.
Still, politicians here are equally bad, if not worse.
It's the same everywhere.
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
The difference in force from gravity on the near side of the star compared to the far side must be enormous.
Does anyone know how close this star is to its Roche limit, or equivalent for gaseous bodies?
"Free software as in beer, copy protection as in racket" - Telsa Gwynne
But how long does it take for the Moon to move the length of a football field??
#2 (Michigan State University, East Lansing) and #5 (Texas Tech University, Lubbock, TX) sure sound like public schools. In looking them up they are actually publicly funded universities.
Time to offend someone
It depends on how many timeouts are called and how many commercial breaks occur.
gravity waves. There should be a very slight decrease in the radius of its orbit.
Wait - isn't trump the guy trying to axe half of the federal government?
Everybody knows that only photons can reach the speed of light in vacuum.
What happens with a solid object if we are starting to accelerate it?
To what speed can it accelerate without losing its physical parameters (by ionization, atomic reactions etc)?
How many Kessel Runs and parsecs does that equal?
I think the point is that this description DOESN'T help. It is just some random "fact" meant to make retards feel like they now know something. It takes me 20 minutes to get to work... its 15 miles. This is way faster. Does that help?
Why don't you take a physics course and find out? Or google it?
General relativity tells you what happens as velocity approaches the speed of light.
To what speed can it accelerate without losing its physical parameters (by ionization, atomic reactions etc)?
None of this happens in a vacuum.
In the real world with objects and particles smashing into things, mechanical and aerospace engineering often deals with these issues, and materials engineering is the discipline that tackles the issues head on.
E.g., on the Space Shuttle, the thermal tiles would ablate during reentry (burn off, essentially, into plasma).
But due to time dilation, from that star's perspective the metric system was only invented in the 19th century.
I was thinking, "this is great! I can go hang out there for a few days and come back to Earth years from now".
Unfortunately, 1% only gives a time dilation of about 1.01
t' = t/sqrt(1 -v2/c2)
Really, you have to get to well over 90% the speed of light if you want Trump's presidency to be over in a few hours.
Wow, that would suck, 5 tide shifts an hour, or considering the menstrual cycle likely evolved its period from the Moon... nm, I don't want to thing about it,
That would be S0–2, a star orbiting Sagittarius A* - the gigantic black hole at the Milky Way's center.
S0-2 has a longer orbit than 47 Tucanae X9, because it is highly elliptical, but at closest approach to Sagittarius A* is reaches 5000 km/sec. The speed of 47 Tucanae X9 is 3500 km/sec.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
Now I want to spin up a fluid dynamical model to model the tides from that! I wonder what the hell that would look like? Guessing lots of oscillating tides with an occasional super-tide where some of the waves stack.
Velociraptor = Distiraptor / Timeraptor
This has been out for twelve hours and even though TFS says "whizzing around a vast black hole", not ONE comment about "your Mom" or "Uranus"?
Are we getting THAT old?
They can take my LifeAlert pendant when they pry it from my cold dead fingers.
I can envision a B-rated sci-fi movie where some evil supervillain has a series of beefs against a number of coastal cities.
Mass does not lose its "physical parameters"-
But the closer it comes to the speed of light the heavier it gets, it gains mass. That means, to accelerate it further, you need more power, but mostly you will again: just increase its mass and not its speed. Hence it can not reach the speed of light.
However in labs we accelerate electrons or protons to something like 99.9% of c.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Are you remembering to account for the time dilation induced by the gravity of the black hole, as well?
#2 had sizeable Endownment during the last couple decades: https://en.wikipedia.org/wiki/...
Also #5 had endownment passing a billion dollars in 2014.
So maybe, just maybe the research mentioned in TFS was funded through these endowments :)
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
We still shove hundreds of horses under a car hood to measure it's power
To be fair, civilized countries are slowly changing to report a car's power output in Watt (kilos of them, even)
Alternatively, it's just as valid to say that GP's entire tax contributions to date covered the cost of a few metres of road near his house, and that everywhere else he/she drives, visits, steps foot in, gets treated at, etc, are all paid for by someone else. Including this research.
Why would anyone engrave "Elbereth"?
I'd use "similarly" instead of "alternatively", because both variations prove the same point.
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
What kind of time dilation effects are we talking?
It only gains mass if you are hellbent on stating that E=Mc^2. Since the star is not at rest, it would be better to state that E^2 = (M^2 c^4) + (p^2 c^2). That way, as the momentum (p) changes, the energy of the object changes the way you expect; but you don't have that concept of "things have more mass when they go fast".
It is the TOKEN act what matters. A dispute with Mexico over immigration is affecting research funding some way. It is not good when the mass will only understand RESEARCH BUDGET CUTS. Though it could be media that is not fully professional on this, and why am I making this comment in a thread for astrophysics?
But why do you need a fluid dynamics model? Consider a rock (a "test particle") on the far side of the Moon, and the forces on it - it's gravitational attraction by the Moon ; ditto from the Earth ; it's inertia. Will the forces on the test particle push it into the Moon, or away from the Moon? Repeat for next particle, with a slightly smaller Moon mass. You're treating the Moon as a strengthless agglomeration of weakly-interacting particles - which is one way of looking at a fluid.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Ok ok let's not do the Kessel run in less than 12 parsecs...
1% the speed of light eh? and yet my g/f complains I go to fast ;)
Mass doesn't lose its "physical parameters"e, true. But a physical object does! I have a spaceship. It is accelerating by some means. My question is: at what speed approximately it becomes a "set of protons and electrons" instead of its normal shape? To what speed it can accelerate without losing its shape?
My question is: at what speed approximately it becomes a "set of protons and electrons" instead of its normal shape? At none?
To what speed it can accelerate without losing its shape? As close to c as you want, why do you think your ship would lose its shape?
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.