Exploring Sounds of Pulsars & Beyond

[subzero0137]

I'm slightly confused as to why and how we record "sounds" from space using radio-waves. Take for example, objects like pulsars on this website: http://www.jb.man.ac.uk/pulsar/Education/Sounds/

So do pulsars really sound like this? Do they actually produce a knocking/ticking sound? Or are these sounds entirely artificial, and just another way of representing the period nature of the "pulses"? Also, can we record "sounds" of objects that emit visible light, instead of radio waves?

 

[Vanadium 50]

They are not sounds. (In space nobody can hear you scream.) They are radio signals interpreted as sound - it's exactly the same as making a graph of intensity vs. time: this interprets the radio outpuit as a graph you can see. But pulsars don't look like that.

 

[davenn]

yup :) the first one I clicked on was that really slow one. As they become faster it becomes just a buzz

visible light doesn't have a sound ( you could receive a visible light signal and mix it with another signal source and you would be able
to hear variations in the light frequency
Radio waves don't have a sound as such either. the pulses of sound you are hearing are the demodulated radio signal pulses

You have listened on a short wave receiver to Morse code being transmitted ? its pretty much the same thingDave

 

[davenn]

just to maybe further your interest
There are all sorts on natural radio signals that can be received. Here are several I have received over the years of experimenting ...
1) Whistlers and Dawn Chorus -- these are generated in the Earth's upper atmosphere ... very low frequency ( VLF) 10 - 20 kHz
2) solar flares --- large wideband bursts of noise, I used to easily monitor them on 50MHz
3) Jupiter noise -- quite a distinct "humming-roaring" noise best received around 20 - 23 MHzcheers
Dave

 

[subzero0137]

Thanks for the replies.

To summarise, there's no sound in space but light, especially radio-waves can be interpreted as sound.

In the case of most pulsars, the sound effect is like that of knocking/beating on something like door. But must it be a knocking/ticking sound? Why can't it be a beeping sound, or any other periodic sound?

 

[davenn]

To summarise, there's no sound in space but light, especially radio-waves can be interpreted as sound.

That statement really doesn't make any sense

In the case of most pulsars, the sound effect is like that of knocking/beating on something like door. But must it be a knocking/ticking sound? Why can't it be a beeping sound, or any other periodic sound?

because they are short period unmodulated pulses .. beeping would infer a tone modulated signal

Dave

 

[subzero0137]

Well that is what Vanadium 50 said, unless I misunderstood him?

Okay, so by "unmodulated", you mean in its natural/original state, right? So the sound of a pulsar is literally and objectively a knocking/clicking sound of a specific pitch and frequency - namely, the pitch/frequency associated with knocking on a door or table, right?

 

[Vanadium 50]

So the sound of a pulsar is literally and objectively a knocking/clicking sound of a specific pitch and frequency - namely, the pitch/frequency associated with knocking on a door or table, right?

No. A pulsar is silent. The sounds are human creations, with one input being the radio output of a pulsar.

 

[Joe Martin]

In space, as many people have said; nobody can hear you scream. There is absolutely no sound in space. None. You may ask; "But what about radio waves...we can hear them?". Well...not really. Can you hear the music from a radio station with just your ears and nothing else? The sound is simply interpreted by us humans on Earth and turned into a sound that makes sense. Basically.
*screams*

 

[D H]

Well that is what Vanadium 50 said, unless I misunderstood him?

You misunderstood him.

People long ago realized that scientific visualization is a very powerful tool for presenting scientific data that, strictly speaking, has absolutely nothing to do with what we see. Our eyes are very, very good at seeing patterns in two dimensional data, so it makes sense to come up with a visualization that let's us see the variations in the data at an intuitive level.

What about one dimensional data? Our eyes aren't so good at "seeing" patterns in one dimensional data. "Seeing" patterns in one dimensional data that varies over time is exactly what our auditory system excels at doing. Just as data visualization (presenting data in as an image) is a very powerful tool for portraying multi-dimensional data, data sonification (presenting data as a sound) is a very powerful tool for portraying one dimensional data that varies over time.

There is absolutely no sound in space. None.

You wrote "absolutely" and "no". That's a bit strong. Strictly speaking, that absolutely is not true. There is sound in space. However, it is extremely low frequency sound, frequencies so very, very low that a person couldn't hear it. ("Hearing" these sounds would require having a lifespan in the tens to hundreds of million years.)

Space is not a perfect vacuum. At long enough time scales and large enough distance scales, the interplanetary / interstellar / intergalactic media looks like a gas. It has a density (extremely low), a pressure (extremely low), and a temperature (varies all over the map). Like any other gas, the gas that comprises outer space can support sound.

An upper limit on the sound frequency a gas can support is the mean free path divided by the speed of sound. Given the extreme paucity of material in space, the upper frequency on sound in space is extremely low, many tens of octaves below what we humans would call "sound".

 

[Joe Martin]

/

You wrote "absolutely" and "no". That's a bit strong. Strictly speaking, that absolutely is not true. There is sound in space. However, it is extremely low frequency sound, frequencies so very, very low that a person couldn't hear it. ("Hearing" these sounds would require having a lifespan in the tens to hundreds of million years.)

Of course that is indeed the case, sorry for the confusion. What I really meant was that as far as we humans are concerned...It damn well is!