Hubble deep field, the most amazing picture of our universe.

(a tiny 🧵 thread)
1/ I learned so much from this recent paper by @tobyordoxford (h/t to @anderssandberg for tweeting)

This thread is based on that paper, so if you’re intrigued, highly recommend reading the entire thing arxiv.org/pdf/2104.01191…
2/ One of the most awe-inspiring insights from the paper is that many of the galaxies we see in the Hubble deep field image are FOREVER beyond our reach.

I don’t mean just practically, but even theoretically.
3/ We can see a distant galaxy but we can never reach it.

Why?

Because our universe is expanding and this expansion is accelerating.
4/ The distance between Earth and the distant galaxy was much less when the light left that distant galaxy than it is now.

And if we start travelling towards it at light speed we’d never be able to reach it because the space between us is expanding even faster.
5/ The most important insight from the accelerated expansion of universe is that we can only affect 5% of the universe we can observe.
6/ The term “observable” universe comes from the fact that since the time of Big Bang (13.8 billion years ago), there has only been a finite right of space around Earth from which light has had time to reach us.
7/ So even though universe most likely extends much, much beyond the observable universe, we can’t see anything from our telescopes beyond this sphere of 400 billion galaxies (which is 46 billion light years in radius)
8/ Counter-intuitively, as time passes because light gets more time to reach us, our observable universe grows in size but because space is expanding, the affectable universe shrinks.

Which means each year, we can observe more galaxies but reach fewer of them.

Crazy, isn’t it?
9/ From @tobyordoxford’s paper, I also learned about “cosmic time dilation”.

Which is that as space expansion accelerates, since light takes longer and longer to reach us and hence distant events appear slower and slower.
10/ Look at the Hubble deep field image again.

The most distant galaxies here are 30 billion years away, which means they’re forever out of our reach (outside affectable universe of 16 billion years).
11/ Also, the further the galaxies are from us, the closer to Big Bang they would have formed.

So at the very edges of our observable universe, we actually don’t see galaxies but proto-galaxies or plasma (yet to condense into galaxies)
12/ And because of cosmic time dilation, it’ll appear that the furthest galaxies are frozen in time!

Nothing ever happens at the edge of our universe (from our point of view).
13/ Another crazy implication: as we can the sky for intelligent life, if we observe them outside of affectable universe (which is 95% of all observable universe), we’d never be able to interact with them.

So we’d know they exist and are likely thriving but we can never say hi!
14/ If you’re in the mood to watch a video, here’s one by @SEA_YT__ that captures these mind bending implications pretty well

15/ That’s it.

Hope you enjoyed it.

If you know of more humbling or awe inspiring implications of the cosmic scale, do reply!
16/ Typos correction:

“there has only been a finite radius* of space around Earth from which light has””

“as we scan* the sky for intelligent life”

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More from @paraschopra

12 Apr
Crypto is the future of our society.

(a 🧵 thread on my podcast with @balajis)
1/ Balaji is a deep thinker on crypto and its implications.

Formerly the CTO of Coinbase and General Partner at Andreessen Horowitz, he’s believes crypto technologies such as bitcoin will change the world the say way Internet did.

Here's the podcast:

2/ We touch on a lot of topics in the podcast.

• How to assess a strange new thing's potential
• How technologies rise and fall
• How to tell what's a fad and what's real
• How to identify nascent technology that will change the world Image
Read 65 tweets
11 Apr
I bet our descendants will get bored of exploring new planets faster than our ancestors got bored of exploring new lands.

Here’s why.
1/ Unlike distant lands, we can observe space from far.

We know an insane amount of stuff about Mars.

Compare this to Columbus who didn’t even know that the Americas existed.
2/ Unlike exploring the Earth, we have no expectation of stumbling upon another culture or language.

We have no expectation of stumbling upon something new to trade with.

We won’t find cloves or silk on Mars.

Space is barren.
Read 6 tweets
10 Apr
Been looking at my historical chats and emails to understand how I thought about #bitcoin.

I think it’s a great way to adjust mental models for the future.
1/ In a 2011 chat, someone said they’re buying $5k worth of bitcoins (when it was $30 per bitcoin).

I told them I think it’s a bubble :)
2/ As per the emails, I and friends were pretty excited about it in 2013.

Understood the technology properly.

We were even cooking up ideas to make bitcoin transactions simple, like a PayPal for bitcoins.

But at $600 per bitcoin, I decided it was overhyped.
Read 12 tweets
9 Apr
How investing in startups is different from other kinds of investing.

(a tiny thread)
1/ The biggest difference is in mindset.

With startups, you don’t think how they can fail because they almost certainly will fail.

Rather you think about their best case - how big they can get if everything goes right.
2/ Another difference is in valuations.

In a sense, a startup company should be defined by its ability to tell a growth story instead of its size.
Read 14 tweets
6 Apr
All startups belong to an ecosystem that makes or breaks them.

(a 🧵 thread on this mental model)
1/ All startups live in an ecosystem where different businesses directly or indirectly support one another.

e.g in the case of the automotive industry, the ecosystem consists of car manufacturers, parts manufacturers, petrol stations, service centers, car insurance companies.
2/ All of them mutually support the entire ecosystem, which means the growth or decline of one business will directly impact all other businesses.
Read 19 tweets
1 Apr
You've heard of AI. But have you ever heard of IA?

🚀🚀

Today, at @VWO, we're announcing a big shakeup of the A/B testing industry.

(a thread about our breakthrough innovation)
1/ Our mission to help marketing and product teams reduce the effort required for figuring what works best for their business

In 2010 we pioneered the DIY visual editor for business teams for editing webpages and creating their variations for A/B tests without involving IT teams
2/ That innovation cut the effort to launch an A/B test from weeks to hours

But, as anyone who has run an A/B test knows, you still have to wait for weeks in order to start getting statistical significant results about which version is better.

Can we cut that wait time too?
Read 28 tweets

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