Astronomy & Space Exploration

dinostar77

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Don't think this will happen today unfortunately, they had a hydrogen bleed issue earlier which they fixed but have another one now and it's not that long before todays window closes.
Did flick over to the live feed. Not much happening.
 

RedDevilQuebecois

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That would be a failure of epic proportions if the launch cannot proceed today after all the media frenzy around it. That's not even saying about the main geopolitical rival in the Race to the Moon 2.0 having a laugh as well.
 
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Buster15

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Thanks, lads. It blows my mind that humans have put a telescope a million miles from Earth that can identify a component of the atmosphere of a planet 700 light years away! Hopefully there's lots of novel data to come.
Isn't that one of the major benefits of the JWST looking at the infrared spectrum. Each of the elements can have a different colour ?
 

Buster15

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Interesting video by sabine. We will probably never know how the universe began...

Of course it is possible that humanity will never actually know as an indisputable fact.
But you can be sure that we will have extremely robust theories.

In reality, it may well be possible to model the event we term the Big Bang.
 

stefan92

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Isn't that one of the major benefits of the JWST looking at the infrared spectrum. Each of the elements can have a different colour ?
True, JWST can detect wavelength that can be observed from Earth (due to the atmosphere blocking them). And it's by far the biggest optical telescope ever launched into space, gathering about five times as much light as Herschel, that fact alone guarantees unique and new discoveries.
 

stefan92

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I thought the idea was that it could see red-shifted galaxies better, and therefore further "back in time".
There are different reasons for (far) infrared light - redshift as well as emissions that directly occur in that range.
 

marcus agrippa

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Of course it is possible that humanity will never actually know as an indisputable fact.
But you can be sure that we will have extremely robust theories.

In reality, it may well be possible to model the event we term the Big Bang.
I agree.

Tend to be rather sceptical of impossibility claims, because they are often more a reflection of the claimant's lack of imagination rather than a statement of fact. Auguste Comte thought that no one would ever know what the stars were made of. This was in the nineteenth century, when a lot of people imagined that physics was (nearly) complete. He couldn't have imagined the discoveries mere decades down the line.

I'd say given the big problems in the standard model of cosmology, we are definitely missing vital pieces whose discovery could well open up new vistas for investigation.

So I'll stick to Carl Sagan: 'Somewhere, something incredible is waiting to be known.'
 

giggs-beckham

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I thought the idea was that it could see red-shifted galaxies better, and therefore further "back in time".
JWST looks at starlight passing through the atmospheres of planets when they pass in front of their parent star (transit method). Due to its sensitivity it can analyse the light in great detail to determine the chemical composition of the planet (light spectroscopy)
 

Denis79

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Excuse me for my probable lack of basic knowledge here, but what causes a planet to become/remain a gas planet?
As I understand it's mass and distance from it's star (temperature on the planet) decides that. Planets that were formed close to a star are usually solid while those further away become gas giants.
 
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rcoobc

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As I understand it's mass and distance from it's star (temperature on the planet) decides that. Planets that were formed close to a star are usually solid while those further away become gas giants.
I dont know if "distance from star" is still considered a big factor.

The first exoplanets they found were all gas giants close to their stars... Because that was what was easiest to see obviously (large shift in luminesounce, large movement of star).

But certainly there were more than they were expecting from the old "inner planets = small rocks, outer = large gas" theory.

Like you said though these were probably formed far from the star then travelled inwards.

Or maybe everything ive said is out of date now anyway.
 

That'sHernandez

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Excuse me for my probable lack of basic knowledge here, but what causes a planet to become/remain a gas planet?
As I understand it's mass and distance from it's star (temperature on the planet) decides that. Planets that were formed close to a star are usually solid while those further away become gas giants if they have a large mass.
I dont know if "distance from star" is still considered a big factor.

The first exoplanets they found were all gas giants close to their stars... Because that was what was easiest to see obviously (large shift in luminesounce, large movement of star).

But certainly there were more than they were expecting from the old "inner planets = small rocks, outer = large gas" theory.

Like you said though these were probably formed far from the star then travelled inwards.

Or maybe everything ive said is out of date now anyway.
There's what's called a snow line in the solar system, where volatile compounds (water, methane, CO2 etc.) freeze (this line is different for each compound, and at a different point depending on the age of the star, ie protostar, t-tauri or main sequence for example as the Sun is currently) and can be swept up by gas giants, which are likely to have begun with rocky cores themselves. They then retain their composition through strong magnetic fields which deflect the solar winds and their large mass.

With regards to Hot Jupiters it's thought they formed beyond the snow line and then migrated inwards, no doubt ejecting smaller rocky planets as they go. It's been a couple of years since I did planet formation though.
 

RedDevilQuebecois

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The Artemis I launch has been delayed again due to a hydrogen leak; we won't have a launch until a few more weeks. Absolute garbage of a piece of hardware.


Someone will have to explain to me why they are using hydrogen now as fuel when liquid nitrogen has been in use as fuel since the late 1970s and early 1980s up to SpaceX rockets.
 

giggs-beckham

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I didn't even know anything about this until recently.were actually going back to the moon that came out of nowhere.
 

stefan92

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The Artemis I launch has been delayed again due to a hydrogen leak; we won't have a launch until a few more weeks. Absolute garbage of a piece of hardware.


Someone will have to explain to me why they are using hydrogen now as fuel when liquid nitrogen has been in use as fuel since the late 1970s and early 1980s up to SpaceX rockets.
Nitrogen has never been used as rocket fuel, that stuff simply doesn't burn ;)

SpaceX is using kerosene and liquid oxygen.
 

Balljy

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The Artemis I launch has been delayed again due to a hydrogen leak; we won't have a launch until a few more weeks. Absolute garbage of a piece of hardware.


Someone will have to explain to me why they are using hydrogen now as fuel when liquid nitrogen has been in use as fuel since the late 1970s and early 1980s up to SpaceX rockets.
Hydrogen is a legacy of using reconditioned RS-25 shuttle engines for this flight. That's also why it's got SRB's as whilst powerful and efficient the RS-25's don't have the best thrust from the launch pad.
 

giggs-beckham

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My old cats name was Theia :lol:

To be honest I'm really disappointed. If there was one thread on this entire forum I wouldn't expect this kind of thing, it should be this one. I imagine it like a table of people like minded discussing things but if it was you would get respectful discussion and not childish pointing and laughing for little reason. I see it all the time on the rest of the forum so stay mainly out of it..
 
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The Firestarter

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The Artemis I launch has been delayed again due to a hydrogen leak; we won't have a launch until a few more weeks. Absolute garbage of a piece of hardware.


Someone will have to explain to me why they are using hydrogen now as fuel when liquid nitrogen has been in use as fuel since the late 1970s and early 1980s up to SpaceX rockets.
SpaceX uses kerosene for Falcon and methane for Starship. I don't think nitrogen can ever be used ever as rocket propellant , unless purely as pressured gas without combustion - I.e toy water bottle rockets.
On the other hand, hydrogen here is used largely because of the reuse of the old RS-25 engine. It has mostly advantages in the upper (non atmospheric)stages performance and is suitable for heavy lifting (efficient burning).
 

Organic Potatoes

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This lady is saying this is the best time to view Jupiter within our lifetimes, even with binoculars...

 

Invictus

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Piracy on the High Seas.
 

Invictus

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Sir Matt

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I’m curious how much the orbit was altered and if they will be able to extrapolate how we would go about altering future missions dependent on trajectory and size.

Also, how long before someone figured out how to do this but like Marco Inaros in the Expanse?