hajola

Input Output | Senior Bitcoin & Rust Engineers, Fullstack/DevOps, Product, BD, Marketing | Full-Time | Remote (Global) | https://iohk.io/en/career

We're a new venture inside IOHK building the future of Bitcoin DeFi. Our mission is to unlock Bitcoin's economic potential by building a secure, trust-minimized protocol that brings more utility to native BTC.

Tech Stack: Rust, Bitcoin, BitVM (X,1,2,3, and beyond), RISC-V, etc.

We're hiring for a small, mission-driven, and crypto-native team.

If you're passionate about Bitcoin and rigorous open-source engineering, we'd love to hear from you. If interested, please reach out directly to me at hans.lahe [at] iohk.io

Well, we also know where we haven't found signs of life. So from that perspective we have more data.

Probably not the best choice of words from me there. However, there is a positive correlation between a star's metallicity and the number of planets a star has.

Thanks for the clarification. You are absolutely right, in my post above I accidentally used the word "parallel" that caused the confusion. It wouldn't even be practically possible to use PLATO to observe them.

Here's a visual if that's helpful to any reader: https://www.researchgate.net/figure/Geometric-Probability-fo... .

I should have been more clear in my original post. AFAIK there are two options on the table - looking at two fields, both 2 years OR looking at one field for 3 years and then doing "step and stare" for the rest of the mission. Step and stare being that they "step" into a new field, "stare" at it for some time, and repeat.

> How big is the L2 Lagrange point? (i.e., how closely do you need to be for an orbit around L2 to be practical?)

The L2 point doesn't really have size, and even its location isn't stable. It's a mathematical point, and when we say "orbit around L2" then that is not fully true either. The spacecraft are on what's called "halo orbit" - maybe imagine balancing a steel ball (like from a bearing) on a bottle that's sideways, it's probably easier to roll and balance the ball lenghtways of the bottle, than on rolling it sideways. The best analogy I could come up with. You don't want to be too close to the L2 point, as then the orbit would be very short and less stable, think of it as having a smaller bottle - probably harder to balance the steel ball on a smaller bottle than a big one.

> How far away PLATO will be from the James Webb Space Telescope? Probably on the magnitude of hundreds of thousands of kms on average. Interesting question though, hopefully they won't get too close :D

> What's the typical time scale for a transit?

Generally measured in hours, or minutes. For example, if we were observing our system with perfect alignment, Earth's transit would be about 12 hours, Jupiter's transit around 29 hours.

> Also, why use transits instead of the Doppler method?

Quantity. PLATO can observe a sizeable portion of the sky at once, 100k+ of stars. With Doppler method the quantities are smaller + afaik there is a trade-off between number of stars being observed and the velocity we can measure. So to find Earth-like planets around Sun-like stars, we would likely have to go one or a few stars at a time.

> Has this patch of sky been selected based on previous Doppler method star studies?

I am not actively involved anymore. So I am not sure if they have already picked what part of the sky they PLATO is going to be observing. The previous Doppler method (aka as radial-velocity or rv method) star studies play a role, not only because if there's one planet, there might be more, but also because rv gave information about the star. However, keep in mind that this is to find new exoplanets, less to find out more data about existing ones. Rv will definitely be used along side PLATO, to confirm and gather more information about exoplanets that PLATO finds.

For many reasons. 1 - it might be very unique itself 2 - it might be very close to us 3 - it might be orbiting a very interesting star, a star type we didn't expect to have that planet type or so many planets, or so close, or so far, etc 4 - the more exoplanets we discover the more we learn how star systems come to be. the more we know how rare ours is, how it might have formed, etc. It helps us answer age old questions.

Good question. No, these will essentially be black-white "photos". The amount of light is measured. The reason for so many CCDs is so that the field of view would be as large as possible. A larger field of view enables to look at more stars at once. Given that we will be locked into looking at one spot for a whole year, it ups our chances of spotting something cool if we maximise the number of stars we are looking at.

However they won't be photos of planets really. It will be countless photos of the same stars over and over again, it's just that sometimes they will be slightly less bright than other times. Directly imaging exoplanets is incredibly difficult, but humans have managed it: https://en.wikipedia.org/wiki/List_of_directly_imaged_exopla...

Great questions.

> Is it to get a more exhaustive survey single star or can full of stars?

PLATO will look at 100k+ stars at once. And for most we will be unlucky to see a transit between PLATO and the star. Geometrically it won't align - imagine the star systems being in different angles from us. To bring an analogue - Take a pack of cards and throw them in the air, and take a quick picture while they are sitll in the air - how many cards will be facing the camera exactly with their edge. For us to spot a transit, the planet has to pass between us and the star. If the orbital plane is not parallel to us, we will miss the transit. So that's one of the reasons why it helps to look at bunch of stars with transit method. We expect that about 1% of the orbital planes will be aligned so that we can get meaningful data.

> Or does that help it find smaller/further/different planets?

Imagine you are trying to find Earth from another solar system. The longer you look at our Sun the higher the likelihood that Earth will pass between you and the Sun. And once you get lucky, and the Earth transits between you and the Sun, the brightness of the Sun only dips about 0.01%, so that means that in order to find small planets we have to have sensitive instruments and little noise, so that the dip in brightness can be measured. Furthermore, as the planet passes the transit and continues on its orbit, the perceived brightness of the star will increase, due to the planet reflecting some extra light. Measuring that can gives us some rudimentary information about the atmosphere - e.g. if a small planet reflects a lot of light back, maybe it's covered in clouds or snow.

> And how do they pick where to point at?

There's a whole complicated process to find consensus on where to point. Basically they look at spots that have lots of stars, and they look what type of stars they are. Here the objective is to find planets around Sun-like stars, so they would prioritize fields that have more Sun-like stars.

> Is there a way of guessing the likelihood of finding a planet?

It seems that some stars are more likely to have planets than others.

As far as I know it won't be affected at all, the project is almost fully funded from the European Space Agency. And it will most likely be launched with the European Ariane rocket.

Yes that's correct.

Yes, it's something that's referred to as pointing stability. The telescope will have star trackers to precisely know it's relative position - basically you make sure that you see the correct stars from where it is placed on the spacecraft. It will use reaction wheels to make tiny correction's to its position. Imagine you are in a computer chair and trying to spin yourself without feet or hands touching anything, just by twisting your body. Reaction wheels work on the same principle. As Earth completes a year around the Sun, the gravitational pull from other solar system bodies is very minor on PLATO. That said, keeping a spacecraft in L2 is not easy - there is nothing to "orbit".

Figuring out the optimal placement of CCDs on Plato's 24(+2) cameras. Due to the way CCDs are fabricated, their properties vary a bit, they are not identical. For example, they can vary how much light they can hold before they become saturated. Given the high cost of fabricating these CCDs, and the fact that for each camera 4 CCDs are used, and all these 4 have to share front-end electronics, it was prudent to optimize their grouping to we maximise the dynamic range we get. More dynamic range means that we can tell more about the planets we find with higher confidence.

While it's possible for conditions for life to emerge or sustain itself to be present beyond the habitable zone (e.g. there's likely a subsurface ocean orbiting the farthest plant from the Sun on Triton), afawk it is more probable that life forms in the habitable zone. That is the only one we have a data point for.

It might be because we keep discovering more exoplanets. So far we have confirmed 5830 of them ( https://exoplanetarchive.ipac.caltech.edu/ ).

Next year there is a plan to send a space telescope to L2 with the main objective being to search for Earth-like planets around Sun-like stars in the habitable zone.

Like Kepler and TESS telescopes it will use the transit method to find new exoplanets, but unlike any mission before, it's going to look at the same spot in the sky for a whole year. Super excited to see what data it brings back to us.

The telescope is called PLATO ( https://en.wikipedia.org/wiki/PLATO_(spacecraft) )

I contributed to the project a few years back, very happy to answer any questions.

This is awesome. I went looking for FarFarOut ( https://en.wikipedia.org/wiki/2018_AG37 ), maybe would be cool to add it?

Which has upkeep costs due to living in it, and the occasional overnight parking expenses and fines.

There are manufacturing processes that benefit from microgravity (e.g. growing protein crystals for the pharma industry, producing semiconductors, etc).

Beyond that it would be a significant boon for science.

1 billion SATS = 10 bitcoin

1 SATS = 0.00000001 bitcoin

Unsure why the headline was edited. Probably to get more attention as btc draws more attention than SATS

This sounds like scaling the service to more areas will slow :( . Surprising that Alphabet sees the savings to be worth a slower rollout.

It seems it would depend on the persons risk tolerance.

And assessing risk of freely available open source software is still difficult, you either rely on all the authors being standup citizens, or on the bulk of the reviewers to be truthful and knowledgeable.

Auditing each tool by ourselves would cost a lot of time. Not to mention that it would not be a one-time thing. At each update, another check would be required for "peace of mind".

Curious to discuss if there is a way to trust these extensions without establishing ourselves that the code is not harmful.

This looks amazing, but installing the Firefox extension I am worried about all the permissions it asks. I am surprised how comfortable people are signing off on these permissions. How do people at HN put these security worries to rest?

Curious, what is the reason you would consider buying more than 1?

That's not true - they are not always passed on to the customer. It depends. Unless the corporation has a monopoly, it can not just increase the prices. There is a concept in economics called elasticity of demand, to simplify, it states that with increase in price there will be a drop in demand. So corporations have to balance, and in most cases the tax increase will be shared between the consumer and the corporation.

Could you please explain in more detail how a CEO of a profitable massive corporation signaling desire to pay higher corporate income tax is a loss for the economy and the common man.

If anything he might be suggesting in the letter that corporations aren't paying their fair share relative to the common man.

Warren also seemed to strongly hint (quoted below) that Treasury should be getting more of its revenue from corporate income tax. Maybe your quoted part was him reinforcing that point and putting BAs money where its mouth is.

"The $32 trillion of revenue was garnered by the Treasury through individual income taxes (48%), social security and related receipts (34 1⁄2%), corporate income tax payments (8 1⁄2%) and a wide variety of lesser levies. Berkshire’s contribution via the corporate income tax was $32 billion during the decade, almost exactly a tenth of 1% of all money that the Treasury collected. 8

And that means – brace yourself – had there been roughly 1,000 taxpayers in the U.S. matching Berkshire’s payments, no other businesses nor any of the country’s 131 million households would have needed to pay any taxes to the federal government. Not a dime."

Could you elaborate on "the way reviews are incentivized". As I understand it, guests review of the host is only visible to the host after the host has also reviewed the guest or a deadline has passed.

Do hosts look at the reviews the guests have left to previous hosts and that incentivizes the guests not to give bad reviews? Or am I missing something?