[HN Gopher] First pictures from Euclid satellite reveal billions...
___________________________________________________________________
First pictures from Euclid satellite reveal billions of orphan
stars
Author : geox
Score : 127 points
Date : 2024-05-23 13:22 UTC (9 hours ago)
(HTM) web link (www.nottingham.ac.uk)
(TXT) w3m dump (www.nottingham.ac.uk)
| fellerts wrote:
| TFA specifies "more than 1,500 billion". That's more than a
| _trillion_, not "billions"! Why the reluctance to use the proper
| number?
| Rebelgecko wrote:
| The UK used a different definition of trillion until ~50 years
| ago (10^18 vs 10^12), so it probably helps avoid ambiguity
| sammyoos wrote:
| The designation of trillion is ambiguous:
| https://en.wikipedia.org/wiki/Trillion
| philomath_mn wrote:
| Same for one billion: https://en.wikipedia.org/wiki/Billion
|
| I've never heard someone use the long scale, it is only ever
| mentioned as a novelty. I think the scientific community, at
| the very least, has standardized on the short scale.
| pxndxx wrote:
| The long scale is common in French, German and Spanish for
| example. English usually uses the short scale. The
| scientific community uses SI prefixes, which aren't part of
| either scale (you don't say a billion joules which is
| ambiguous, you either say a terajoule for a long-scale
| billion or a gigajoule for a short-scale one).
| piva00 wrote:
| Also common in Swedish, miljon = 10^6, miljard = 10^9,
| biljon = 10^12, biljard = 10^15, triljon = 10^18.
| philomath_mn wrote:
| Fair enough, but I still would be surprised to see the
| long scale used in scientific communications written in
| English.
|
| Re SI Prefixes: you _could_ make the argument that they
| are essential another short scale since they are named
| every 3 orders of magnitude.
| whimsicalism wrote:
| what? the scientific community absolutely also uses
| billion and trillion by short scale
|
| it's all over papers and nobody is ever using the long
| scale that i've seen
| ivan_gammel wrote:
| Are those papers in English? Long scale may be translated
| to short scale if the paper is translated from the
| original language where long scale is common.
| whimsicalism wrote:
| yes, i'm talking about the scientific community - papers
| are almost exclusively published in english or with an
| english version. long scale translated to short scale
| would be a mistranslation, imo
| rob74 wrote:
| The long scale is far from just a novelty, most European
| countries other than the UK use it. Actually I thought it
| was used in all non-English-speaking countries, but
| Wikipedia showed me that the situation is far more
| complicated than I thought:
|
| https://en.wikipedia.org/wiki/Long_and_short_scales#/media/
| F...
|
| Besides short scale and long scale, there is a sizable
| "short scale with milliard instead of billion" fraction,
| and of course some countries (China, India, Japan, Greece)
| have completely different systems. Most interesting is that
| Portugal uses the long scale, while Brazil uses the short
| scale. That must be confusing...
| whimsicalism wrote:
| almost all scientific writing i can find from people in
| portugal uses the short scale. english formal
| communication has standardized around the short scale
| phkahler wrote:
| >> Same for one billion:
|
| So that's how the US government will make the mult-trillion
| dollar debt go away. They'll just call it Billions.
| tzot wrote:
| OTOH the phrase "a thousand million" for 109 is not that
| uncommon. From what I've seen, in places where
| billions/trillions are mentioned and it's important that
| the number is accurately specified, a representation with
| digits or the exponent of 10 are typically provided.
| whimsicalism wrote:
| my understanding is the long scale has largely died out
|
| think it is more than permissible to use what is
| scientifically standard (trillion = 10^12)
| tzot wrote:
| "Scientifically standard" are the SI prefixes. So, given
| the ambiguity of what 1 gigastar is (1/1000th of 1 terastar
| or a really huge star?) one should say "1012s of stars"
| maybe.
| whimsicalism wrote:
| Yes, the SI prefixes are one example of something that is
| scientifically standard. The short scale is another.
| jl6 wrote:
| Billions is not wrong. Trillion _s_ (plural) would be wrong.
| "More than a trillion" would be needless words.
| dylan604 wrote:
| A very famous person is very well known for his particular
| style of enunciating billions. After that, saying any other
| word is just a wasted chance of having Sagan's voice in their
| head reading the word.
| BurningFrog wrote:
| A lot of people outside of HN don't know what a trillion is.
| wrycoder wrote:
| Tell them it's comparable to $1 bills laid end to end from
| here to the sun.
|
| And tell them it's only 1/35 of the US national debt, which
| is roughly $350,000 per US taxpayer.
| s1artibartfast wrote:
| Easy fix, just use $100 bills and we are only 35% of the
| way to sun. Problem solved.
| rurban wrote:
| The proper unit would be Parsec, imho
| seanhunter wrote:
| Parsec is a unit of distance[1]. They were counting a number
| of stars.
|
| [1] Defined as the distance at which 1AU subtends an angle of
| one arc second or 648000/pi AU
| https://en.wikipedia.org/wiki/Parsec
| fnordpiglet wrote:
| I assume this is being hugged to death?
|
| 504 Gateway Time-out
|
| The server didn't respond in time.
| CapitalistCartr wrote:
| HN often Slashdots stuff.
| floxy wrote:
| Website seems down. Alternate links:
|
| https://scitechdaily.com/euclid-mission-uncovers-1-5-trillio...
|
| https://thedebrief.org/euclid-first-look-stunning-new-images...
|
| ...I was under the impression that there was a faint blue glow
| coming from everywhere, that was hypothesized to be extra
| galactic stars. Has there been any follow up on that?
|
| https://en.wikipedia.org/wiki/Intergalactic_star#Observation...
| cuSetanta wrote:
| Always a bit special to see science come from a spacecraft I had
| the pleasure of working on. Honestly there were a lot of issues
| during the build of Euclid that I was very glad to not be a part
| of, but seeing the images coming out of it now is pretty damn
| impressive.
|
| Hope all of the engineers that struggled to get this mission
| spacebourne can enjoy!
| seanhunter wrote:
| Congratulations. That's an amazing project to be a part of, and
| it looks like some really jawdropping science is going to
| result.
| ck_one wrote:
| Can you share some insights on what the issues were?
| PeterCorless wrote:
| We can spot the orphan stars at this distance. However, Euclid
| needs to turn to closer targets than the Pegasus cluster to spot
| rogue planets.
|
| https://www.theguardian.com/science/article/2024/may/23/eucl....
|
| In this case, it found dozens of rogue planets in the Orion
| nebula, which is only 1,500 ly away.
|
| I am presuming there are also going to be great numbers of rogue
| planets in deep space, not tied to any star or galaxy. But there
| would be no way for Euclid to spot them at that distance. Stars
| were hard enough.
|
| I presume, in due time, there will be some sort of calculable
| estimation or projection of orphan stars and rogue planets per
| cubic parsec or kilosparsec.
| floxy wrote:
| >We can spot the orphan stars at this distance.
|
| Can we resolve these individual orphan stars? Or just see the
| cumulative glow from a lot of them?
| PeterCorless wrote:
| Note that there are two different announcements today, and I
| need to clarify my comment above.
|
| * One piece cited viewing 1.5 trillion stars in the _Perseus_
| cluster of galaxies, which is 240 million ly distance:
| https://www.nottingham.ac.uk/news/first-pictures-from-
| euclid...
|
| * The other cited spotted stars in galaxy cluster Abell 2390,
| which is in the Pegasus constellation, which is 2.7 billion
| ly away -- an order of magnitude further away: https://www.es
| a.int/Science_Exploration/Space_Science/Euclid...
|
| If I am reading this correctly, it seems like Euclid was able
| to see the light from individual stars ripped from their
| galaxies in Abell 2390. Which is quite the accomplishment.
|
| Please let me know if I am reading too much into this, or
| reading it incorrectly.
| Ringz wrote:
| It would be interesting to calculate how much these stars
| contribute to the mass deficit of the universe.
| Retric wrote:
| Not just stars, it implies there's a lot of planets,
| asteroids, etc tossed out there.
| recursive wrote:
| I suspect in any solar system, the mass of the non-stars
| are a rounding error compared to the whole system's mass.
| Retric wrote:
| I suspect the current contents of a solar system is a
| poor proxy for everything that's been ejected from it.
| Pluto is 0.0006 light-years from the sun, there's a great
| deal of space between stars we don't know that much
| about.
|
| Further we dramatically underestimated the number of expo
| planets for decades. Quite reasonably we don't put a lot
| of weight on stuff we can't detect.
| SJC_Hacker wrote:
| > I suspect in any solar system, the mass of the non-
| stars are a rounding error compared to the whole system's
| mass.
|
| A brown dwarf orbiting a red dwarf would beg to differ.
| leke wrote:
| It's dead, Jim.
| gcanyon wrote:
| The stars near us in the Milky Way are tens of light years away,
| and we'll have to do some incredible science and technology to
| visit them.
|
| How much worse would it be if you were an intelligent life form
| on a planet orbiting one of those orphans, and the nearest star
| was a thousand, ten thousand, even a million light years away?
| outworlder wrote:
| At some point, given the universe's expansion, galaxies will be
| moving away so fast that the observable universe will be just
| one galaxy. Already, the effective rate from galaxies far away
| is actually faster than the speed of light. Even at light
| speeds, we cannot reach 94% of them as we would never catch up
| if we left today. In cosmic scales of many billions of years,
| observers on every galaxy will eventually think that their
| galaxy is the only one that has ever existed.
|
| Large distance and time scales are rather gloomy.
| dumpsterdiver wrote:
| Indeed, the only hint they would have that they were not
| alone would be the "weak" gravitational effects of all other
| existing matter pulling at the fringes of their visible
| universe. Perhaps they'll refer to this phenomenon as "dark
| energy".
| mr_toad wrote:
| The galaxies in our local group are gravitationally bound.
| wahern wrote:
| Whether that matters depends on the nature of dark energy:
| https://en.wikipedia.org/wiki/Big_Rip In the Big Rip
| scenario, though, all structures are eventually torn apart,
| even atoms. But I gather most physicists think the
| parameters required for this to occur are quite improbable.
| pavel_lishin wrote:
| There is a novel written with that premise as the background! I
| can share the title with you, if you'd like - that particular
| premise is a very small part of the novel.
| belter wrote:
| Impressive photos from the ESA site:
| https://www.esa.int/Science_Exploration/Space_Science/Euclid...
___________________________________________________________________
(page generated 2024-05-23 23:01 UTC)