
12 Billion-year-old signal from the end of the universe's 'dark age' - dnetesn
https://phys.org/news/2020-06-scientists-billion-year-old-universe-dark-age.html
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bhickey
An old friend of mine is one of the authors on this. Their instruments
generate _a lot_ of data. I don't know if this is the case for their array in
Australia, but when he was working in South Africa they had to carry hard
drives out of the country because there wasn't enough fiber capacity out of
the continent.

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lattalayta
I recently found out that that is referred to as the sneakernet, and is
actually still a preferred way to transfer a lot of data.
[https://en.wikipedia.org/wiki/Sneakernet](https://en.wikipedia.org/wiki/Sneakernet)

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EarthLaunch
AWS has a little-known service for trucks transporting 100PB of data in
shipping containers:

[https://aws.amazon.com/snowmobile/](https://aws.amazon.com/snowmobile/)

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wolco
What do their prices look like for 100 pb?

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dexterdog
It's probably not bad compared to the monthly recurring you're about to get
hit with for sitting in all of those bits.

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badosu
A question pops in my head whenever I see news of signal detection from the
early age of the universe.

As the universe expands we can see further in the past since light has been
traveling a longer distance. However, since time has passed to reach the stage
where this distance is significant there's a limit to how far we can see, and
this limit is continually pushed further as the universe expands (and
accelerates expansion).

Now, my question is, how is it possible that we can see so far in the past?
Has the early expansion rate of the universe been much faster than what I
assume that it's still possible to capture these signals, are we capturing
signals spread and reflected over time, or is there some other
explanation/wrong assumption?

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waheoo
The universe is bigger than the observable universe.

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badosu
Is that verified? That would be a reasonable explanation

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waheoo
What do you mean verified? Do you think we're in the center of it?

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badosu
We don't need to be in the center of the universe for that, just less than a
certain distance from the edge.

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waheoo
Well if the furthest stuff we can see all happens to be the same distance away
from us, that would mean the universe is larger than the observable, unless
were in the center, which, as history shows, is a bad assumption to make.

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ComodoHacker
Can someone ELI5 how sparse neutral hydrogen could physically emit signal so
strong it could travel this far and be detected? Like, there were no stars, no
nuclear reactions, no interactions with energy exchange(?)... Who lost all
that energy?

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torrance
The emission is the so-called ‘forbidden’ hyperfine transition of the spin
state of Hydrogen’s one electron. It’s flips from spin up to spin down, and
the energy difference is a photon at about 1420 MHz.

It’s called forbidden because it’s extremely unlikely to occur - so unlikely
that I don’t believe it’s been observed in the lab. But in aggregate, with
vast vast clouds of hydrogen it becomes likely enough and strong enough to
detect.

We observe this emission from hydrogen in our own galaxy and through the local
universe. And it’s quite strong to easily detect.

In this experiment, they’re looking for that same 1420 MHz signal, redshifted
down to something like 180 MHz (where exactly it is isn’t known for sure).

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ComodoHacker
Thank you!

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danans
> This radio telescope consists of 4,096 dipole antennas

Does anyone know the significance, if any, of there being 2^12 antennas?

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jandrese
Probably a 64x64 grid.

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danans
But why 64x64 then?

Is that just to match some characteristic (i.e . number of inputs) of the data
aggregation/logging device (more likely), or is it something about the physics
of the type of signal they are trying to detect (less likely)?

There are, after all, plenty of possible square grid combinations bit only
some are powers of 2.

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praveen9920
It must be for separating the visible area into smaller grids for analysis.

I also assume some level of error correction is needed and pair of antennas
data need to be somehow correlated

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MichalSternik
Honest to god question: do you think there's a market for moving encrypted SDD
drives in big european cities?

For stuff that could not and should not be transfered over network.

I had this idea for a bicycle messenger & hardware encryption startup, but i
don't have any idea what the demand really is like.

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rpadovani
I would have used that 3/4 times during the last year in a big EU city: we do
consulting, and one of our customer is adamant their data cannot go on the
public cloud. So they have their own data center, and some file sharing
utility. Problem is, you need to go through their VPN, that is super slow, and
their sharing utility closes connections after a while.

Result: transferring 30/40 GiB of data is painful, and we often go to their
office to retrieve the data instead of using the Internet. In an ideal world,
I wouldn't need a service like the one you suggest, but since a lot of our
customers seems to be in the Stone Age, I would probably use it.

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savrajsingh
It’s amazing that we think this is even possible to achieve — pick up a
particular signal that’s been floating around since the beginning of the
universe and get interesting info from it... would be so cool if they manage
it!

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oh_sigh
Floating around doesn't do it justice....it's been flying at the speed of
light away from its origin for the past 12 billion years until it ran into a
little sensor.

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divbzero
I wonder if the kangaroos hopping by create any interference that they need to
correct for.

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flycaliguy
Not likely. I worked at a research station right down the road from a zoo and
we didn’t see any interference from any of the animals. Now, the security
fence on the other hand? Static City we used to call it.

