h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Extrasolar Planet Groundbreakers - A87824686
Author: Galaxy Babe - eclectic editor - U128652



GB

Guessed it was from you, before I clicked through onto this thread

Looks fine to me... I don't really know a great deal about such things, but it read through in one go, straight-forwardly... and most seemed to make sense to me, though as the concepts are a bit forign to me, I'd probably need a few reads to take in all the names and suchlike

Maybe ends a little abruptly...

This is amazing, as it suggests there are many possible planets, in varied positions round varied stars.

I have a few detailed comments.

In the first section, after 'At times people suffered for their beliefs,'it might be clearer if you add a phrase like 'about the universe'

In the section 'Closest companions', what do you mean by saying the planets' orbits are in resonance with each other?

In the section'Say Cheese',I feel I'm missing something. Do you mean the gas giant is in the circumstellar disc?

Hi 2legs and mvpThanks for your reviews and comments. I have:

Added to the ending for 2legs

Added 'about the universe' for mvp

In the section 'Closest companions', what do you mean by saying the planets' orbits are in resonance with each other?
For every 10 orbits of the inner planet, the outer planet has exactly 7. So every 10 "years" (their time) they line up. I've added that info to the Entry



In the section 'Say Cheese', I feel I'm missing something. Do you mean the gas giant is in the circumstellar disc?
No, I mean they were the first to be photographed. If the header is too cheesy, I'll try and think of something else

andagain

GB

I've added an Extrasolar Planet Nomenclature subheader and tried to explain why the planets are called "b" "c" etc. Let me know if it doesn't make sense, or needs further explanation, please

GB

Thank you for adding the piece about extrasolar planet nomenclature.
I don't mind the header 'Say Cheese', I just didn't see the connection between the first and second sentence in this paragraph. I think it might be clearer if you expanded the paragraph - something like this: 'Beta Pictoris was found to have a surrounding outer, debris disc and an inner clear zone. Gas giant Beta Pictoris B was detected in the clear zone in 2003 and subsequently directly imaged by ESO in Chile'

It makes sense... to the scientists I guess... but... surely they could have come up with a simpler system err... so, yeh, that bit makes sense to me, anyhow... I think oo, yes, the ending seems to read a bit butter to me, though I know of course can't quite remember how it was to start with, or what you've changed

Hi again both, oh dear confusion reigns!

I've expanded the paragraph as you've suggested, mvp.



2legs - yes, they could have named all the planets but then we'd have to remember all the names...

The ending originally said: (Header) The Future - "We're awaiting the announcement of the discovery of alien life on an extrasolar planet not unlike Earth orbiting within its star's habitable zone. It shouldn't be too long now..."

I've expanded it somewhat as per your request



GB

But.. but... its easier for people, to remember names they're familiar with.... we could have 'plannet Bob', 'plannet John', 'Plannet Susan' and 'plannet Chay' etc...

Damn, I was thinking Vulcan, Ferenginar, Kronos, etc...

Oh... wlel... if you must!

I think 'plannet Gladis' or 'plannet Dorathy' have a certain 'ring' to them... Not sure about 'Plannet Tarquin' though... I must stop derailing Pr threads like this

*runs to read the entry again*

By the way, I'm impressed by your list of references.

Hi GB. Another great entry!

I know you won't mind me pointing out a few things...

"an aged pulsar (rapidly spinning neutron2 star) in the constellation Virgo. Any planets in the vicinity would not have survived the initial blast,"

You talk about the initial blast, but it's not clear what you're talking about because the explanation of the supernova explosion is in a footnote which the reader may not have read. I think you should move the information from a footnote to an actual explanation in the text.

"they may be captured asteroids" -- I don't understand this. Asteroids are small planets that orbit a star. But haven't you already said that any such planets would be blown away or burnt up by the supernova explosion?

"All three 'pulsar planets' would fit within the orbit of Mercury if they existed in our own Solar System." -- this seems to say that the planets are smaller than the orbit of Mercury, when you mean to say that their orbits are smaller than the orbit of Mercury. I'd say something like:

"All three 'pulsar planets' are very close to their parent star - their orbits would fit within the orbit of Mercury if they existed in our own Solar System.

"that still makes HIP 11952 b and HIP 11952 c the most elderly planets yet detected." -- you've admitted that the planets are not the same age as the star, so why do you think that they must be very old?

Mu Arae c, discovered in 2004, turned out to be just six times the mass of Earth -- I think it's worth explaining at this point that within our own solar system there are two main types of planet - the gas giants which are very much bigger than the Earth (between 15 and 300 times as massive as the Earth), and the rocky planets that are much the same size as the Earth or smaller. Mu Arae c, because it is only six times the mass of the Earth, is assumed to be a rocky 'terrestrial' planet.

"Multiple star systems are quite common throughout our galaxy, solo stars like our own Sun are less so." -- I believe this is only true of the visible stars. If you take the much dimmer red dwarfs into account, I believe that solo stars far outnumber the binaries.

Minor punctuation suggestion:

were treated harshly, -- change the comma to a semicolon

Hi everyone

2legs, you are most welcome in my PR threads, I need to know that my astronomy entries are readable by the layman

mvp - thank you, I already knew most of these stars as I listed them in my constellation entries (or have added them to others since they were written) but the references are always useful for viewers or future updaters

Gnomon - thank you very much! I know if my astronomy entries get past you then I've done a good job.

"an aged pulsar (rapidly spinning neutron2 star) in the constellation Virgo. Any planets in the vicinity would not have survived the initial blast,"
You talk about the initial blast, but it's not clear what you're talking about because the explanation of the supernova explosion is in a footnote which the reader may not have read. I think you should move the information from a footnote to an actual explanation in the text.

done

"they may be captured asteroids" -- I don't understand this. Asteroids are small planets that orbit a star. But haven't you already said that any such planets would be blown away or burnt up by the supernova explosion?
captured asteroids would be moons, like Mars' two moons. They wouldn't be planets as they have to be spherical. I have to admit they're an enigma! I have changed the Entry to read: "Scientists hypothesise that they were probably created from a debris disc, or they may be asteroids captured by the star's gravity post-supernova." - I hope that reads better,

All three 'pulsar planets' would fit within the orbit of Mercury if they existed in our own Solar System." -- this seems to say that the planets are smaller than the orbit of Mercury, when you mean to say that their orbits are smaller than the orbit of Mercury. I'd say something like:

"All three 'pulsar planets' are very close to their parent star - their orbits would fit within the orbit of Mercury if they existed in our own Solar System.

done

"that still makes HIP 11952 b and HIP 11952 c the most elderly planets yet detected." -- you've admitted that the planets are not the same age as the star, so why do you think that they must be very old?
I've changed the text to:
"They are likely several million years younger than their parent star because planets tend to coalesce from the star's debris disc, but that still makes HIP 11952 b and HIP 11952 c the most elderly planets yet detected."

Mu Arae c, discovered in 2004, turned out to be just six times the mass of Earth -- I think it's worth explaining at this point that within our own solar system there are two main types of planet - the gas giants which are very much bigger than the Earth (between 15 and 300 times as massive as the Earth), and the rocky planets that are much the same size as the Earth or smaller. Mu Arae c, because it is only six times the mass of the Earth, is assumed to be a rocky 'terrestrial' planet.

done

"Multiple star systems are quite common throughout our galaxy, solo stars like our own Sun are less so." -- I believe this is only true of the visible stars. If you take the much dimmer red dwarfs into account, I believe that solo stars far outnumber the binaries.
I've changed it to read: "Multiple star systems are quite common throughout our galaxy."


I believe I've answered all your queries, I've also tweaked the minor punctuation suggestion

Thanks very much for all your help

GB

Interesting

Just a few little things I wasn't clear about when I read this:

"The first success was muted" - what does that mean?

In the Rocky Pair section, "The discovery of the smallest extrasolar planet so far was announced on 10 January, 2011." - made it sound like there were no smaller ones found since 2011, but I see later there have been...

"Fomalhaut is the luminary of Piscis Austrinus." - what does that mean?

Why is PH1 not named the same as the others?

Hi Sasha

Thanks for reading and reviewing

"The first success was muted" - what does that mean?
They didn't crack open the champagne. I've footnoted that



"The discovery of the smallest extrasolar planet so far was announced on 10 January, 2011." - made it sound like there were no smaller ones found since 2011, but I see later there have been...
I've changed that to "up till then"



"Fomalhaut is the luminary of Piscis Austrinus." - what does that mean?
It was supposed to mean "brightest star" so I've changed that



Why is PH1 not named the same as the others?
because it was the first one detected by the Planet Hunters (citizen science) I presume



I've also added the info I just discovered that the IAU *are* taking nominations for extrasolar planet names, and linked to the pdf.

GB

Is it me, or is the title rather worrying? It sounds as if these extrasolar planets are crashing into things.

tinfoilhat smiley

It's supposed to be a pun. Did it fail miserably? I can put "The First Extrasolar Planets" or "Extrasolar Planetary Finds" or "Extrasolar Planets - the first discoveries" but they aren't as catchy IMHO.

GB

It might get a few more people reading, if they thought as I did!