Hacker News new | past | comments | ask | show | jobs | submit | alfiopuglisi's comments login

It's quite difficult with current rocket technology: you have to counteract most of the Earth-given 30km/s speed around the Sun in order to get close (it's smaller than Mercury's orbit), and then brake again to circularize the orbit once you are there. I am not sure that it can be done with what we have now. That said, it's not that far off either.

7.2 grams a day is still a lot. Low-sodium diets aim for less than 3 grams a day, and it is not that difficult to go even lower. Whether a near-zero sodium intake is good or not, it's another can of worms, but a study looking at a huge-salt diet vs. a high-salt diet does not look very useful.


Before refrigeration sodium consumption was 10x


Well, at least they don't sell seed oil :)


The ring is not a product of the supernova. It's pre-existing material, that is being energized by impact of the supernova ejecta (it took a few months for it to start brightening).

There are actually three rings, a smaller one around the previous star's equator, and two larger ones above and below. The hourglass-like figure is actually quite common, produced by the star rotaton.


It's a limitation of the Falcon Heavy, the launcher used this time. A future, more powerful one could do it while being reusable.


Sure, a bigger rocket could carry this particular payload while being reusable. But for any rocket there will always be payloads it can't carry while also having enough fuel to land.


That constraint can be significantly mitigated by in-space refueling. Then it just becomes a matter of what the rocket can lift into a stable orbit.

Edit: Not that this applies to any currently operational rockets.


It goes on until an Earth's day is as long as a month. Both will face each other in a fixed way. But it takes many billions of years and the Sun will burn both to a cinder much before that.


It's not so uncommon in science to come to a strange conclusion by excluding all "reasonable" alternatives. For example, black holes have a similar status: no one has conclusively seen one, but we know of no mechanism for matter to support itself beyond a certain density, so black hole it is.


Have we not pointed telescopes into space and seen the way light bends around a black hole? I guess in a way it's true that nobody has conclusively "seen" one (since they don't emit light), but by that logic nobody has conclusively seen the hole in the middle of a donut either.


> but by that logic nobody has conclusively seen the hole in the middle of a donut either.

Not quite..we can see the donut hole very clearly, put things through it, measure it, interact with it. We can measure and observe and test it however we like.

Not so with a black hole. Yet.


I guess I don't understand...what is going on here? https://eventhorizontelescope.org/


My understanding is that the EHT images are a result of a lot (like, months) of data processing, not an image from the telescope. So arguably still not a direct observation.


Digital photographs are just the result of processing the sensor readings of photodiodes. It seems quite arbitrary to say one is an "image" and the other isn't just because the processing step is more complicated. Both accurately represent what you would see if you were there in person (ignoring false color etc.).


Exactly this.


> It's not so uncommon in science to come to a strange conclusion by excluding all "reasonable" alternatives.

That is not what happen in the article, or to my understanding in this field of research.

> For example, black holes have a similar status: no one has conclusively seen one, but we know of no mechanism for matter to support itself beyond a certain density, so black hole it is.

Comparing the equation based methods of physics, often called a "hard" science, to neurology or biology, often called a a "soft" science, is not going to be an apples to apples comparison.


> neurology or biology, often called a a "soft" science,

Neurology and biology are absolutely hard sciences, just as hard as physics.


No, absolutely not.

(my phd is in biophysics; I've worked across many different fields)


Yes, they absolutely are. Congrats on your PhD.

Hard sciences are simply those that can be tested and verified. Biology and neurology fall into this category.

Soft sciences are those that don't lend themselves to testing and verification very well, like economics and psychology.

This is pretty cut and dry. It's not like trying to argue if Star Wars is sci-fi or not or something.


There is a continuum of hardness within the quantitative sciences, and physics definitely lies on the "more testable and verifiable" than chemistry, biology, and neuroscience (not neurology- that's a form of medicine). Many of the biological systems we work with, we don't even really test and verify, especially not at the level that a large-scale particle physics experiment would.

If you want to insist that biology is as testable and verifiable as physics, I have no interest in arguing with you- it's just a difference of opinion (and I think people with experience across the continuum would agree with me).


> If you want to insist that biology is as testable and verifiable as physics, I have no interest in arguing with you- it's just a difference of opinion

I just think the whole "There is a continuum of hardness within the quantitative sciences" is irrelevant. It's more of a binary thing, and biology is a hard science, period. But sure, we can agree to disagree.

Without any doubt though, biology is not a 'soft' science.


You seem to agree that the testability is not binary:

> Soft sciences are those that don't lend themselves to testing and verification very well, like economics and psychology.

But want hard to only used in a binary fashion with some heuristic triggering the step function from soft to hard.

People do talk using the term that way. They also use it as a continuum saying one field is harder than an another. I quoted the terms, "hard" and "soft" in my message above because the terms are used in a few different ways and are not rigorously defined. They only need a rough definition to make the point I was making though.


> Neurology and biology are absolutely hard sciences

Sometimes.

> just as hard as physics.

No. Not even close.


Neurology maybe, specially with the book "The Rhythms of The Brain". Still far from pure Physics.

Biology it's more about classification/sorting than Math.


> Sometimes.

No, always. No exceptions.

> No. Not even close.

It's exactly equal because it's a category not a scale and certainly not a competition.

Hard sciences are those that can be tested and verified. Biology, neurology and physicals all meet that criteria, and thus are all hard.

Soft sciences are those that are harder to test, like economics and psychology.


This sounds like the whole "we've never seen a species evolving". Much like fossils, radioactive dating, geology come together to give us a picture of evolution, we have tons of real evidence for black holes. But we even have two actual pictures now.


yes, but in this case, nobody has excluded all the more probable alternatives.


I am in Italy as well and the link works fine.


The link i get is :

https://imgur.com/a/RSQIKP2

STOP !

PAGINA INTERDETTA DAL CENTRO NAZIONALE PER IL CONTRASTO DELLA PEDOPORNOGRAFIA ONLINE (C.N.C.P.O.)

Il tuo browser sta tentando di raggiungere un sito Internet contenente immagini e filmati di pedopornografia minorile. L'inibizione dell'accesso a questo sito é prevista dalla legge n. 38/2006.

Questo servizio di protezione della navigazione sulla rete Internet è predisposto grazie alla collaborazione tra il Centro Nazionale per il Contrasto della Pedopornografia Online e gli Internet Service Providers italiani.

La visualizzazione intenzionale, la diffusione, la detenzione, la cessione, la produzione e la commercializzazione di questo tipo di materiale sono puniti dalla legge come reato.


The Danish authorities abuse their filters in a similar way. It's just about the children ..!


What if that's just some illegal content that was reported? Even archived on purpose in the first place. Would that result in banning the whole domain?


The day your wish is fullfilled is the day I stop working with Python. I can't stand all those useless braces everywhere, why are they there at all since good practice mandates proper indentation anyway?

I am at the point where I prefer single quotes for strings, instead of double quotes, just because they feel cleaner. And unfortunately pep8 sometimes mandates double quotes for reasons unknown.


Single quotes are also easier to type on the default layout, no Shift


No need for braces. Just add "end" for marking block ending to match the already block starting keyword ":".


A while ago, when thinking about syntax design for a new language, I considered this combination (`:` and `end`, as opposed to `do` and `end` as used by Lua etc).

Are there any languages that use it, or is Python unique in using `:` to begin a block?


Nim uses it too.

IIRC, Python's predecessor (ABC) didn't have the trailing colon but they did some experiments and found it increased readability.


Not just the Netherlands, most of Europe counts floors like this: ground, first, second, etc.


> Not just the Netherlands, most of Europe counts floors like this: ground, first, second, etc.

I think it wildly differs all around Europe.

In Spain for example, if someone says "1st floor" it can be two or three floors above the actual ground floor, if there is a "Entresuelo" or "Principal", and you start counting after those. Actual ground floor is "bajo".

On the other hand you have the "atico" (attic) which is the top level floor, unless there is a "sobre atico" ("above the attic"), so just because you live in the attic doesn't mean you live on the top floor.

Then every region can have their own convention, or even difference in neighborhoods in the same city.


They count ground, first in the country in Europe where GP is from. In turn they generalize based on nothing to most-of-Europe.

Call it the Ugly European effect. https://blog.codinghorror.com/the-ugly-american-programmer/


I'm not sure how many countries in Europe count like that, the online information is totally unreliable. For example: https://www.reddit.com/r/MapPorn/comments/mvnkja/floor_numbe... That map is absolutely incorrect for a bunch of countries, e.g. the Nordic ones.


Sure, but not everywhere, and I was just addressing the specific example.


I've heard even some programmers like 0-based indexing. Crazy!


and Australia...


Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: