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In the early 2010's there were many popular articles that said that the total bandwidth of the the Square Kilometer Array's optical fiber network for raw data from each dish would be larger than the Earth's internet. Here is just one example:

Wikipedia's Square Kilometre Array :

It would require very high performance central computing engines and long-haul links with a capacity greater than the global Internet traffic as of 2013.3

As you can see that link is broken.

The SKA project has several Precursors, pathfinders and design studies but the SKA proper has not been built yet, and perhaps is not even finalized.

Still, with available data, by the time it might be built (2025?) is it likely to still exceed the Earth's internet's bandwidth?

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    $\begingroup$ one quick query - do you mean traffic or bandwidth? Bandwidth is higher than traffic, as traffic is only the used bandwidth, not the total available $\endgroup$
    – Rory Alsop
    Jan 7, 2019 at 11:19
  • $\begingroup$ @RoryAlsop either will do. $\endgroup$
    – uhoh
    Jan 7, 2019 at 11:22
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    $\begingroup$ @Rob I've been reading Python all day and can't remember how to read English now. Can you say more explicitly which is 1900x bigger than which? (Earth internet versus SKA) $\endgroup$
    – uhoh
    Jan 7, 2019 at 12:21
  • $\begingroup$ @Rob the 10 PB is compressed, raw data is 1 EB, 100x larger. Next step is to see if they will be compressing and expanding each dish's link at each end in real time, or not. $\endgroup$
    – uhoh
    Jan 7, 2019 at 12:38

1 Answer 1

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Will the SKA's total bandwidth still exceed the Earth's Internet's bandwidth?

No.

First some conversions:

  • 1024 Gigabytes = 1 Terabyte
  • 1024 Terabytes = 1 Petabyte
  • 1024 Petabytes = 1 Exabyte
  • 1024 Exabytes = 1 Zettabyte

From the SKA Telescope website: "The Operational Model" (.PDF), on the webpage: "Info Sheets", this explanation and graphic is offered:

"The data journey

  • Basic data products will be produced and stored in Cape Town for SKA1-mid and Perth for SKA1-low. From there, they will be delivered to a global alliance of SKA Regional Centres for further processing and archiving and access by the user community.

  • New data models will need to be developed as current software packages for radio astronomy data reduction don’t have the capabilities to handle the SKA’s large bandwidths and Field of View dataset.".

SKA Data Path and Bandwidth

"Major dates

SKA1 OPERATIONAL CONCEPT DOCUMENT - Operational Principles

  • late 2027 - Commencement of Key Science Projects (KSPs)

  • late 2026 - Commencement of PI-led programmes

  • 2024–2027 - Key Science Project (KSP) planning & proposals

  • 2022 - Start of Observatory & Science commissioning

  • 2020 - Start of construction activities

  • 2017–2018 - Prototypes deployed at the telescope sites"

See also: "SKA Community Briefing – 18 January 2017", page 12:

Data Flow through the SKA

Nothing will flow to /dev/null.

Source: Cisco - Global - IP Traffic: https://www.cisco.com/c/m/en_us/solutions/service-provider/vni-forecast-highlights.html#

  • Globally, IP traffic will grow 3-fold from 2017 to 2022, a compound annual growth rate of 26%.

  • Globally, IP traffic will reach 396.0 EB per month by 2022, up from 122.4 EB per month in 2017.

  • Global IP networks will carry 13.0 EB per day by 2022, up from 4.0 EB per day in 2017.

...

Internet Traffic

  • Globally, Internet traffic will grow 3.7-fold from 2017 to 2022, a compound annual growth rate of 30%.

  • Globally, busy hour Internet traffic will grow 4.8-fold from 2017 to 2022, a compound annual growth rate of 37%.

  • Globally, Internet traffic will reach 350.8 EB per month by 2022, up from 96.0 EB per month in 2017.

  • Global Internet traffic will be 11.5 EB per day by 2022, up from 3.2 EB per day in 2017.

  • Global Internet traffic by 2022 will be equivalent to 1 trillion DVDs per year, 88 billion DVDs per month, or 120 million DVDs per hour.

  • By 2022, the gigabyte equivalent of all movies ever made will cross the Internet every 1 minutes.

  • Global Internet traffic by 2022 will be equivalent to 193x the volume of the entire Global Internet in 2005.

...

No, it's not even close.

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    $\begingroup$ I don't see your math. These are just pasted images. There will ultimately be 7,000 SKA-mid dishes, and each dish will have its own fiber. Have you calculated that? $\endgroup$
    – uhoh
    Jan 7, 2019 at 13:59
  • $\begingroup$ Question asks for a comparison of two numbers and asks which is larger. That wasn't even attempted here. I'm voting for this to be deleted as it doesn't attempt to answer the question. $\endgroup$
    – uhoh
    Jan 12, 2019 at 2:03
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    $\begingroup$ I've cleaned up some comments here, and I'll ask folks to please keep it civil. I think that @uhoh does have some valid concerns, and they're constructive critiques; please don't just dismiss them. Rob, I think you could make this answer better by maybe cutting a lot of the graphics and rephrasing things in your own words; it makes it kinda difficult to address the OP's specific question even if the numbers are still in there somewhere. In its current form, I don't think this answer is as useful as it could be - but I also think it's partway to where it needs to be. $\endgroup$
    – HDE 226868 ♦
    Jan 12, 2019 at 3:13
  • $\begingroup$ @HDE226868 - Uhoh made an edit which I rolled back after an earlier comment wasn't addressed. People can ask certain things but it's not the responsibility of the answerer to explain everything beginning to end to the complete satisfaction of all comers. My comment that from time to time he asks people to clarify every aspect of everything is also a valid concern. Neither is everyone obligated to like the answer as-is. I will refrain from answering his questions (which unlike mine represent a third of his activity) on the SE sites going forward. Emailing a complaint will be my last resort. $\endgroup$
    – Rob
    Jan 12, 2019 at 12:44
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    $\begingroup$ Speaking as someone just reading the answer, I have to say that the given answer is not supported in that it doesn't actually show BOTH numbers and how they were derived. $\endgroup$
    – Donald.McLean
    Jan 15, 2019 at 18:39

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