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dekhn 9 hours ago [-]
I don't think the title is really accurate- it doesn't emit radio signals every 8 minutes, it emits constantly, but emits along an axis that periodically aligns with our viewing cone.
sandworm101 7 hours ago [-]
There is an underlying tension in astronomical language. For over a thousand years "star" was a thing in the sky, a bit of light one could point a telescope at. We today understand stars not as lights but as giant objects billions of miles away. Which definition is used changes according to context. A steady beam that intermittently points towards earth can be described using either definition: It is a light in the sky that pulses, or it is aspherical star emitting a beam as it rotates. Both are correct.
dekhn 7 hours ago [-]
I've never heard any astronomer I've worked with say that. What people said for a thousand years (incorrectly) is mostly irrelevant to modern science.
What I'm saying is that it's tecnically incorrect to say " emits radio signals every 8 minutes " because it emits constantly. Emission is different from detection.
adolph 4 hours ago [-]
Yes, it is incorrect and yes it is how language works. Even a "co-author on the paper" calls them "pulses" which maybe straddles the definition of periodic emission and detection.
Associate Professor Natasha Hurley-Walker, co-author on the paper, said that the pulses emitted by the white dwarf allowed the team to detect stellar flares on the Sun-like star, similar to those that create aurorae here on Earth.
dekhn 1 hours ago [-]
Thanks for pointing this out, it's a good point (specifically that the co-author misspoke).
sandworm101 7 hours ago [-]
"Sirius is the brightest star in the night sky"
I have heard that phrase from many. But Sirius is nowhere near the brightest star. Sirius is only brightest if one uses the "light in the night sky" definition of a star. Under the "ball of plasma" definition, Betelgeuse is far brighter than Sirius. Betelgeuse is visible to the eye and is many times brighter than Sirius... just not from our perspective of looking up at lights in the sky.
The brightness from our perspective might not be interesting to stellar astronomers, but to someone like a ship's navigator or NASA engineer building a satellite's navigation system, apparent brightness of a "star" is everything.
GavinMcG 5 hours ago [-]
Brightness is necessarily measured from a particular viewpoint. The fact of emission isn’t. Neither has anything to do with how “star” is defined.
philipov 6 hours ago [-]
Your semantic argument is comparing apples and oranges, and therefore fails. The semantics of the word "emit" are not like the semantics of "brightest in the night sky." The first describes an objective action, while the second describes a subjective detection. You sneakily drop the "in the night sky" to try to turn a subjective statement into an objective one, but this is deception.
Why yes, I am a linguist.
nacnud 2 hours ago [-]
absolute and relative magnitude
dekhn 7 hours ago [-]
Are you an astronomer?
MisterTea 5 hours ago [-]
Their profile does not hint at that.
sandworm101 6 hours ago [-]
Lol, are you a linguist?
I have taken enough stellar astronomy undergrads to understand that "star" is a nuanced term, that "Which is brightest?" is a loaded question on an exam. Read any astronomical journal and you will see splits between the physics/math types who discuss stars as balls of gas, and the observer/telescope types who talk of them as lights to be seen. And anyone reading history can witness how often the definition of "star" has changed over time, and continues to change to this day.
unrented7977 6 hours ago [-]
People also said the earth was flat for thousands of years. Stop intentionally conflating incorrect casual vernacular with actual scientific language. You are, quite simply, plain wrong.
sandworm101 5 hours ago [-]
"Pulsar" = Scientific term. They do not pulse, except from our perspective (the light-in-the-sky definition). Pulsars have kept the name and are regularly described as pulsing objects when discussed the context of observations. Want to build a telescope to study pulsars? Then you will plan for them being pulsing dots of light.
"Neutron Star" = Scientific term. But is not a star by accepted scientific definition. (Also "Quark Stars", which remain mostly mathematical but are still not stars.)
Science is full of ancient terminology. Being imperfect or having more than one meaning does not make a term "casual vernacular".
vhantz 4 hours ago [-]
Yeah words have an history. Google etymology.
Should every phenomenon be renamed as soon as our knowledge of it depens? Or should we wait until we have reached an understanding of the thing in itself until we dare name a phenomenon? Both of these are obviously impractical, useless and harmful options for science and society at large.
alex_c 3 hours ago [-]
"Wow, look! It's a hippo's head!"
"Well it's probably a whole hippo, it's just the rest of him is under the water."
rq1 8 hours ago [-]
“long-period transients“
What wait, 8mn is a long period?
I checked the fastest pulsar observed rotates and “emits” at 716Hz! :shock:
That’s ~70.000km/s on the equator given its ~30km diameter :shock: :shock:
It really is difficult to truly understand the absurd energies involved in these things.
alterom 8 hours ago [-]
Twinkle twinkle little star 0_0
dekhn 7 hours ago [-]
Take a look also at quasars, which are supermassive black holes at the center of galaxies, fed by enormous amounts of matter falling into the gravity well.
testingonetwo34 7 hours ago [-]
"The equatorial surface velocity of PSR J1748−2446ad is approximately 24% of c"
Why would you send signals at a fixed interval? That would instantly label you as a natural phenomena instead of organic intent
Make it random, at least receivers would have a harder time identifying intentions
nikhilgk 8 hours ago [-]
Or primes
8 hours ago [-]
jMyles 7 hours ago [-]
They give us food, which Esoqq can't eat!
cartan 9 hours ago [-]
Nuke them before it's too late!
flippyhead 7 hours ago [-]
Transmit one of our recursively improving AI to them, maybe?
dmonitor 3 hours ago [-]
That's a good way to replace one problem (potential alien invasion) with another (potential borg takeover)
throwaway81523 9 hours ago [-]
Pulsars are usually faster than that I guess.
stronglikedan 6 hours ago [-]
If this thing has been sending repeating signals for what I presume to be a very long time, shouldn't we have already detected it? Or is it that we've always been able to detect this particular signal, but have only just now traced it to its source?
itintheory 7 hours ago [-]
Sounds like the OnOff star from A Deepness in the Sky by Vernor Vinge. It started with very quick oscillation and eventually settled toward 200 years off, 60 years on (or so). Interesting speculation about what this would do to a developing species/society.
phailhaus 7 hours ago [-]
Unfortunately the headline is misleading. It's constantly emitting radio signals, it's just spinning in a way that points at us every 8 minutes. Great book though!
teeray 8 hours ago [-]
A light shining in the dark forest...
martijnvds 10 hours ago [-]
The signal? "Replace smoke alarm battery"
bombcar 10 hours ago [-]
Then it would be periodic but so long between signals that it would be nearly impossible to determine where it was coming from.
gibolt 9 hours ago [-]
Maybe it is a musical instrument smoke alarm
alterom 6 hours ago [-]
Wow. I guess they have seen everything now.
hilariously 9 hours ago [-]
What's that beep?
Eh, we'll figure it in the next galactic epoch, go back to bed.
ocastx 9 hours ago [-]
We are on our way, Carol!
1970-01-01 6 hours ago [-]
All I got from this is pulsars aren't long period transient stars "because that's why".
Seriously, if data doesn't fit the classical definition, you need to update the classical definition.
I didn't know that there was a whole slew of these red and white dwarfs orbiting other stars, which I think must make it extra unlikely for there to be habitable planets in the same system, the process of one star capturing another is going to realy wreck havock with any original planets,
and any surviving lifeform to get past the am radio phase of technological development
thats! GPM J071507−114153, "the pulse on your dial" brought to by astrophyisal phenominon, every 8 min, for eterinty
combobyte 7 hours ago [-]
Most binary star systems are not captures, they formed together from the same stellar nebula.
sidewndr46 7 hours ago [-]
So, why don't they just form one bigger star?
combobyte 7 hours ago [-]
The same general reasons that allow planets to form instead of all the mass going into a single star: mass/momentum/charge asymmetries in the original stellar nebula, complex interactions in the accretion disk, gravitational perturbations from other stars in the same stellar nursery, etc
Ah, sorry. I can't hear song lyrics, so those tend to be lost on me!
rtkwe 9 hours ago [-]
Yes but repeated evenly spaced pulses are special and limited to a special subset of stars caller pulsars. The sun is mostly wideband radio noise where the article is talking about distinct regular pulses which are rarer.
You responded to a “joke” but hey this is cool new info for me
ErroneousBosh 9 hours ago [-]
If you have satellite TV you already have a solar radiotelescope.
Measure the voltage on the AGC line in the tuner and you'll see a peak as the sun passes the azimuth of the dish. That's it picking up 10GHz solar radiation, and turning its gain down to compensate for the background noise.
AstroNutt 9 hours ago [-]
I got it! :)
There is no Joy in this HN Division.
TZubiri 2 hours ago [-]
HN is dead, we need a new order in here
whalesalad 7 hours ago [-]
so... a pulsar?
villaaston1 4 hours ago [-]
Pulsars have a much shorter period and we’re quite sure what they are. 4,000+ have been discovered in the Milky Way alone.
Objects with a period this long are much rarer, according to this wp article there are only 12 we know of. I thought it was fewer!
What I'm saying is that it's tecnically incorrect to say " emits radio signals every 8 minutes " because it emits constantly. Emission is different from detection.
I have heard that phrase from many. But Sirius is nowhere near the brightest star. Sirius is only brightest if one uses the "light in the night sky" definition of a star. Under the "ball of plasma" definition, Betelgeuse is far brighter than Sirius. Betelgeuse is visible to the eye and is many times brighter than Sirius... just not from our perspective of looking up at lights in the sky.
The brightness from our perspective might not be interesting to stellar astronomers, but to someone like a ship's navigator or NASA engineer building a satellite's navigation system, apparent brightness of a "star" is everything.
Why yes, I am a linguist.
I have taken enough stellar astronomy undergrads to understand that "star" is a nuanced term, that "Which is brightest?" is a loaded question on an exam. Read any astronomical journal and you will see splits between the physics/math types who discuss stars as balls of gas, and the observer/telescope types who talk of them as lights to be seen. And anyone reading history can witness how often the definition of "star" has changed over time, and continues to change to this day.
"Neutron Star" = Scientific term. But is not a star by accepted scientific definition. (Also "Quark Stars", which remain mostly mathematical but are still not stars.)
Science is full of ancient terminology. Being imperfect or having more than one meaning does not make a term "casual vernacular".
Should every phenomenon be renamed as soon as our knowledge of it depens? Or should we wait until we have reached an understanding of the thing in itself until we dare name a phenomenon? Both of these are obviously impractical, useless and harmful options for science and society at large.
"Well it's probably a whole hippo, it's just the rest of him is under the water."
What wait, 8mn is a long period?
I checked the fastest pulsar observed rotates and “emits” at 716Hz! :shock:
That’s ~70.000km/s on the equator given its ~30km diameter :shock: :shock:
https://en.wikipedia.org/wiki/PSR_J1748%E2%88%922446ad
https://en.wikipedia.org/wiki/Black_hole_bomb
Make it random, at least receivers would have a harder time identifying intentions
Seriously, if data doesn't fit the classical definition, you need to update the classical definition.
thats! GPM J071507−114153, "the pulse on your dial" brought to by astrophyisal phenominon, every 8 min, for eterinty
https://en.wikipedia.org/wiki/Solar_radio_emission
https://en.wikipedia.org/wiki/Radio_telescope
https://en.wikipedia.org/wiki/Pulsar
Measure the voltage on the AGC line in the tuner and you'll see a peak as the sun passes the azimuth of the dish. That's it picking up 10GHz solar radiation, and turning its gain down to compensate for the background noise.
Objects with a period this long are much rarer, according to this wp article there are only 12 we know of. I thought it was fewer!
https://en.wikipedia.org/wiki/Long_period_radio_transient