The Square Kilometre Array: Radio silence for most powerful telescope in history | Hacker News Reader

The Square Kilometre Array: Radio silence for most powerful telescope in history

theguardian.com

88 pointsbart42_034 comments

Some of the prototype designs for the aerials are currently being made by a bloke called Pete, in the room next to me. He keeps his bike locked to a table and it gets in everyone's way, so we let his tyres down occasionally. They don't tell you that sort of thing in articles like this.

They also don't tell you that the SKA is in south africa, with portions built in australia.

Don't they?

"Once the project is properly under way – with arrays at this site and another in a remote area of South Africa – it will in effect make up the biggest radio telescope the world has seen. At Murchison alone there will be 130,000 radio antennas in the first phase, and maybe a million in the second, taking care of the lower frequency end of the project"

"The telescope will be perhaps 10,000 times more powerful than any we currently have"

"Right now we can spot planets circling around distant stars. The SKA will be able to spot the equivalent of an airport radar system on one of those very, very distant planets."

"visitors must be prepared for, scheduled in and accounted for when looking at the data this place produces. Long before you get to Boolardy, the 346,000-hectare pastoral station on which the Murchison observatory stands, the radio-quiet restrictions start. Anyone approaching is asked to turn off all electronic devices."

Incredible that the age we live in, we section off large swaths of land just so we can read radio waves from planets so distant we will likely never visit them. I'm glad the Australian government is getting behind something like this and look forward to seeing what they uncover.

On a side note, the actual writing of the article irked me a bit as the reporter is clearly non-technical, and when I saw Moores overquoted Law get a mention it did make me reconsider the accuracy of other statements made by the writer.

It's maybe worth noting that while the space is indeed large, it's not actually used for anything much. The human impact of turning of electronic devices is negligable, given there is no cellphone reception anyway. In Karoo (where most of SKA will stand, in South Africa) they indeed turned off a few radio towers for cellphones and the site is radio-free (you can only use computers in isolated containers) but it only affected a few farmers. Asking people to turn phones off in one plane is probably far more of a hassle :-)

Incredible that the age we live in, we section off large swaths of land just so we can read radio waves from planets so distant we will likely never visit them.

We're not looking for places to visit. The reason we do space science (and lots of other fields of science) is that the more fundamental knowledge we have about the universe, the closer we can get to understanding how the universe is the way it is, and that makes it more likely that we'll be able to solve problems we have here on Earth.

Ignoring the fundamentals, the desire to do astronomy has lead to more than a few useful inventions. Figuring out how the sun works is the basis for our research in to fusion, which could lead to solving humanity's energy problems forever. The charge-coupled device in every camera in every smartphone was originally developed for astronomy. GPS only works because we can use satellites to track deep space objects. Aperture synthesis in MRI scanners (combining several images in to one image the size of all the cameras combined) came from combining the results from telescopes together.

A big field in Australia is a tiny price to pay for what the SKA could come up with.

Many things result in technology being developed. War, for example, creates vast amounts of technology (including rocket technology, satellite etc) , but that is not a good reason to engage in warfare.

That's not the same thing at all. The benefits of a destructive pursuit don't make it a more attractive thing to do. They're in opposition to the negatives of the original action. The side effects of a constructive pursuit do make it a more attractive thing to do because they are in addition to the already positive result of the original action.

I don't disagree! In fact I firmly believe that the ends never justifies the means.

But I wonder how many people would consider a major war to be beneficial if it lead to real fusion ie. limitless clean energy for the world, the end of energy poverty, of nuclear fission, and end of global warming.

I read it as "this is a good thing, an incredibly good thing, that we devote land to pure science".

You may be interested in https://en.wikipedia.org/wiki/United_States_National_Radio_Q...

Residents in this part of West Virginia can't have cell phones, Wifi, and you can't even drive a car with spark plugs within a mile of the telescope.

It looks like all the restrictions on common consumer equipment are only within a 20 mile radius. The restrictions in the major part of the zone are on high power transmitters (i.e. TV and radio broadcasts).

This is an interesting point. It can work out the other way. The Thirty Meter Telescope, a very large segmented mirror optical telescope, is being built on top of Mauna Kea in Hawaii. Construction is being protested by activists for desecrating the mountain:

https://en.wikipedia.org/wiki/Thirty_Meter_Telescope_protest...

and a pretty good listicle here:

http://www.huffingtonpost.com/2015/04/13/hawaii-telescope-pr...

The technical challenges posed by the SKA really are astoundingly huge. The data generated by these dishes will require much higher data throuput than even the fastest optical links between CERN and its tier 1 sites (40 Gb/s), and they will be in the middle of a remote desert. Then there is the scale of compute and storage needed to analyse the data, which would be totally unfeasible with the tech we have today. It's an exciting time to be working in scientific computing!!

Well, that's as much because CERN doesn't need additional throughput than anything else; technically it's a solved problem, which makes it one of the easier ones to do something about :)

We can quite easily send 40Gb/s over a single fibre (I feel like I've seen over a terabit done...), and the undersea cables (more inhospitable than the remote desert) are far, far higher bandwidth.

Consuming the data in a timely manner may be tricky, though!

> and the undersea cables (more inhospitable than the remote desert) are far, far higher bandwidth

Terrestrial cables are likely harder to lay: you have to worry about land access—national parks, native title, private land—and the W.A. outback is an extremely challenging environment to work in.

Getting dedicated DWDM fibre to Murchinson is a big project unto itself.

The optical private network from CERN to the tier 1 site where I work was upgraded from 10 Gb to 40 Gb between the first and second runs of the LHC. depending on what goes on during the second run that might need to be increased again. Building high bandwidth infrastructure for use by lots of (paying!) customers is probably more viable for large corporations than it is for science, where you have a budget at the start rather than having things pay for themselves over time

The storage will need to constantly increase in that time, too.

Yes, of course, but this seems to be a problem where the solution is easily costed, is commercially available etc, whereas I'd imagine that the rest of the project is filled with a whole load of world-firsts.

Tier 1 = fermilab?

The NSA can do it, maybe they should contribute some engineering effort to help scientific causes like this and gain some good PR in the process.

CERN had a similar problem too, and the only solution was just to throw away a lot of their data. Do you expect this might happen with SKA, or is the hope that they can capture everything for later processing?

It depends - the amounts of data involved are mammoth by today's standards, but the idea is that we will develop new methods and tools to make the project feasible. The announcement and funding of the SKA will probably help this process along too, as specific challenges are addressed throughout the programme

From the article:

    There will be far too much data for it all to be simply recorded.
    The plan is to "use an algorithm to reduce that data down to a
    smaller magnitude that you can then process further on a super
    computer", Morgan says.

So excited that this is happening in my backyard :)

FYI, there are quite a few openings to support the SKA:

http://www.seek.com.au/jobs/in-wa/#keywords=csiro&location=3...

  1. Service Manager, Pawsey Supercomputing Centre
  2. Murchison Radio-Astronomy Observatory (MRO) Support Officer
  3. Senior Software Engineer / Architect
  4. Head of Supercomputing
  5. Australia Telescope National Facility (ANTF) Head of Engineering Operations

They have some interesting stuff in their GitHub repo: https://github.com/ska-sa

Slides about one of the projects to assist scientists with simulations: https://speakerdeck.com/gijzelaerr/rodrigues (Gijs gave the talk yesterday at the Python Amsterdam Meetup)

There was discussion here a few weeks back about the US National Radio Quiet Zone which folks may be interested in as well:

https://news.ycombinator.com/item?id=9569718

https://en.wikipedia.org/wiki/United_States_National_Radio_Q...

Could someone with some knowledge please elaborate on the potential implications on a project such as this, for example, if we found ourselves with clusters of low earth satellites streaming high-bandwith internet to the entire planet?

An educated guess, but I suppose LEO is far enough for them to be able to filter out the signal in software.

Kind of would block out a whole range of frequencies though, right? Dozens of transiting satellites, transmitting at a fairly constant volume, but of random data?

Not necessarily. From what I heard, with an array antenna you can actually separate the scalar and vector (directional) component of incoming signals and ignore those coming from particular direction. So you could either track (in software) and ignore signals from particular points (satellite), or pretty much configure your array to be directional.

That's fascinating. But then also makes you wonder why they have gone to such extents to extinguish any radio signals in the vicinity of the project

If I were to guess, here are several reasons:

- radio signal power goes down with square of the distance, so closer sources are much stronger than far ones

- any (be it software or hardware) filtering is not perfect, so a strong enough signal will probably still drown the weak ones

- it may be tad more difficult to filter out a close source because you can't assume it radiates in parallel lines, which to some extent you can with far ones (like for most practical purposes here on Earth we assume that sun rays are parallel)

- strong signals close to the ground means lots of reflections, which means more strong signals coming from random directions

- it's probably cheaper to make an exclusion zone in the middle of a desert rather than shielding yourself and upgrading the tech even more to filter out all the surrounding RF noise

Yes, satellites are a problem. However they transmit in narrow frequency windows so you deal with this by simply notching out those frequency channels. You do need to make sure that there isn't so much power in the intereference that it does nasty things like send amplifiers into compression.

(source: I am a radio astronomer)

Is the area a no fly zone?

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