Astronomy / The Universe

[Cade]

Aye the next crewed Artemis is doing the same trip, just a slingshot around the Moon then back home.

 

They're not even using Artemis/Orion to conduct the next Moon landings; that's down to SpaceX and Starship.

[Maple Leaf]

7 hours ago, JFK-1 said:

 

What got him was as it ignited then began to build thrust just before lifting off the vibration is phenomenal and the rocket says this guy is swaying wildly. To the extent he was thinking it's going to fall apart and topple over.

 

Of course it didn't but no one had told him this is what it would be like, you're going to think this rocket is going to shake to pieces and fall over.   

 

The Saturn V rocket was about 360 feet tall.  If the nose swayed only a couple of feet, which would not be noticeable to observers, it would be very disconcerting to someone inside, especially if they weren't warned ahead of time.

 

I've also read that the astronauts in the space shuttle were always surprised at the noise and vibrations during lift off.

[ri Alban]

6 minutes ago, Maple Leaf said:

 

The Saturn V rocket was about 360 feet tall.  If the nose swayed only a couple of feet, which would not be noticeable to observers, it would be very disconcerting to someone inside, especially if they weren't warned ahead of time.

 

I've also read that the astronauts in the space shuttle were always surprised at the noise and vibrations during lift off.

Takes some balls to put yourself in one of those contraptions. Risk and reward, tho. 

[JFK-1]

2 hours ago, Maple Leaf said:

I've also read that the astronauts in the space shuttle were always surprised at the noise and vibrations during lift off.

 

I don't know if Artemis and the Saturn V are launched in the same manner as the shuttle. But there was a thing about a shuttle launch I had noticed and seen explained.

 

At ignition as thrust built the shuttle would try to lift off, but was actually tethered and even slightly pulled back down as it tried to lift, you can clearly see it in this clip. You will see it straining to lift, lifting just a fraction, then being pulled back before it then lifts.

 

That too must create massive movement that could be extremely disconcerting.

 

 

 

[JFK-1]

Some of you might be interested in a new documentary released on amazon prime just a couple of days ago. It's about the twin rovers spirit and opportunity NASA landed on opposite sides of Mars in January 2004.

 

This was planned as a 90 day mission since that's all the time they thought they would get before the rovers would malfunction or be destroyed by a storm or something. In the event spirit travelled Mars for 5 years.

 

Two years into the mission spirit had broken one of it's front wheel which meant it couldn't travel forward anymore. The only solution was to drive it backwards dragging the broken wheel with it. By 2009 after 5 years spirit was now down to just 4 of 6 wheels and was stuck. End of journey.

 

Opportunity on the other hand continued on alone for another 9 years making a total of 14 years active before sending the final transmission following a Mars wide dust storm in July 2018.

 

Aside from all the interesting science the film demonstrates a peculiar fact. These NASA people became attached to the robots in the way you would a beloved dog. Any problem for the robot could elicit the same type of distress and tears your sick or injured do would. Seems humans can bond with anything.

 

The film is called 'Good Night Oppy' referring to the opportunity rover which lived for 14 years. This is a trailer.

 

 

 

[JFK-1]

Posting a video below with Neil deGrasse Tyson commenting on the current progress of the Artemis 1 mission as new images of the moons surface are returned. He also actually touched on something I had speculated in an earlier post.

 

Is this drive for the moon which I think was began by Bush the younger, in part a response to declared Chinese intentions of doing so? I thought so and Neil does too. He added something on to that.

 

"If some adversary came out right now and declared an intention to put military installations on Mars, (yes Mars not the moon) we would be there in 10 months"

 

I seriously doubt that, if they left tonight it would take 9 months just to get there and that's just for a one way trip like the probes and rovers. If you want to come back it's at least 21 months.

 

So that's unrealistic but he knows it, he's using exaggeration to state if there had been anybody else trying to do such things over previous decades, we would already be there and have been there first. And I do believe that.

 

There is only one space superpower and that's the US. The US has a gigantic lead over China in all aspects of space from rockets to anything a rocket may be used to launch, including humans. And now they're in the process of enhancing that lead even further.

 

He's also going to comment on news reported just yesterday that the Mars perseverance rover has found evidence of organic molecules, the building blocks of life, on a Mars that was once watery. 

 

And in passing I like Neil, great fun character and a hive of interesting knowledge. But still, despite being an actual student of Carl Sagan, he isn't Carl Sagan. No disrespect to Neil but that's another level in my view.

 

 

 

 

[henrysmithsgloves]

Seen this mentioned a few years back about Ben Rich,ex skunkworks director.

https://www.secretprojects.co.uk/threads/lockheed-skunk-works-ben-rich-comments-revealed.5048/

[ri Alban]

Neil is a total tit. Doesn't even know what the second highest mountain on the planet is called. He just likes the sound of his own voice and talks over everyone.

 

[Cade]

Neil DeGrasse Tyson is a recognisable face but he does talk a load of old shite sometimes.

 

These days he's wrong more than he's right and needs to step back from the limelight before he ruins his own legacy and becomes a joke.

[Bigsmak]

4 hours ago, ri Alban said:

Neil is a total tit. Doesn't even know what the second highest mountain on the planet is called. He just likes the sound of his own voice and talks over everyone.

 

 

What does that have to do with being a Astrophysicist?  

 

Would a Doctor know a good knot to tie up a boat? 

or a Lawyer know how to plaster a wall properly? 

[Maple Leaf]

10 hours ago, ri Alban said:

Neil is a total tit. Doesn't even know what the second highest mountain on the planet is called. He just likes the sound of his own voice and talks over everyone.

 

He's usually pretty good, but sometimes he slavers.

He was a guest on Bill Maher's show a few weeks ago and he didn't make much sense.  I think he must have had a couple of cocktails before the taping began.

[Unknown user]

6 hours ago, Bigsmak said:

 

What does that have to do with being a Astrophysicist?  

 

Would a Doctor know a good knot to tie up a boat? 

or a Lawyer know how to plaster a wall properly? 

No, but I bet they'd both know the second highest mountain in the world

[hughesie27]

On 26/11/2022 at 06:09, JFK-1 said:

Some of you might be interested in a new documentary released on amazon prime just a couple of days ago. It's about the twin rovers spirit and opportunity NASA landed on opposite sides of Mars in January 2004.

 

This was planned as a 90 day mission since that's all the time they thought they would get before the rovers would malfunction or be destroyed by a storm or something. In the event spirit travelled Mars for 5 years.

 

Two years into the mission spirit had broken one of it's front wheel which meant it couldn't travel forward anymore. The only solution was to drive it backwards dragging the broken wheel with it. By 2009 after 5 years spirit was now down to just 4 of 6 wheels and was stuck. End of journey.

 

Opportunity on the other hand continued on alone for another 9 years making a total of 14 years active before sending the final transmission following a Mars wide dust storm in July 2018.

 

Aside from all the interesting science the film demonstrates a peculiar fact. These NASA people became attached to the robots in the way you would a beloved dog. Any problem for the robot could elicit the same type of distress and tears your sick or injured do would. Seems humans can bond with anything.

 

The film is called 'Good Night Oppy' referring to the opportunity rover which lived for 14 years. This is a trailer.

 

 

 

That looks worth a watch. Cheers.

[ri Alban]

20 minutes ago, Maple Leaf said:

He's usually pretty good, but sometimes he slavers.

He was a guest on Bill Maher's show a few weeks ago and he didn't make much sense.  I think he must have had a couple of cocktails before the taping began.

I used to enjoy listening to him and others on The Universe tv series. But him and the other Chinese American, have lost the plot.

[maroonlegions]

 

Astronomers working on the data acquired by the Infrared Survey Telescope for Astronomy in Chile of our central bulge have released their findings for peer review that suggest the 'extragalactic structure' is in fact a Galaxy cluster containing 58 or more Galaxies that has been avoiding our gaze in the Zone of Avoidance .... appropriately enough.

Sounds like another job for James Webb , Space detective.

"Located approximately 3 billion light-years from Earth, the mysterious structure appears to be a large cluster of galaxies drawn together by a shared center of gravity. Using observations from the VVV Survey — a survey that studies the Milky Way's central bulge at infrared wavelengths using the Visible and Infrared Survey Telescope for Astronomy in Chile — the study authors found evidence of at least 58 galaxies bundled together in a small plot of the zone of avoidance.

Galaxy clusters are the largest gravitationally-bound objects in the universe; the largest known clusters contain hundreds of thousands of galaxies bunched together. Unfortunately, it's impossible to tell just how wide or massive the newly discovered cluster is, given the vast distances and myriad obstructions sitting between the cluster's stars and Earth.

However, the mere detection of this colossal object shows that the zone of avoidance may not be as inscrutable as was once thought. Future infrared studies — including potential observations by the James Webb Space Telescope, which has already used its infrared camera to take the deepest image of the universe to date — should further help scientists unlock the hidden secrets beyond the Milky Way's bulge."

 

www.livescience.com...

[henrysmithsgloves]

Latest from James Webb telescope 

[Maple Leaf]

13 hours ago, maroonlegions said:

 

Astronomers working on the data acquired by the Infrared Survey Telescope for Astronomy in Chile of our central bulge have released their findings for peer review that suggest the 'extragalactic structure' is in fact a Galaxy cluster containing 58 or more Galaxies that has been avoiding our gaze in the Zone of Avoidance .... appropriately enough.

Sounds like another job for James Webb , Space detective.

"Located approximately 3 billion light-years from Earth, the mysterious structure appears to be a large cluster of galaxies drawn together by a shared center of gravity. Using observations from the VVV Survey — a survey that studies the Milky Way's central bulge at infrared wavelengths using the Visible and Infrared Survey Telescope for Astronomy in Chile — the study authors found evidence of at least 58 galaxies bundled together in a small plot of the zone of avoidance.

Galaxy clusters are the largest gravitationally-bound objects in the universe; the largest known clusters contain hundreds of thousands of galaxies bunched together. Unfortunately, it's impossible to tell just how wide or massive the newly discovered cluster is, given the vast distances and myriad obstructions sitting between the cluster's stars and Earth.

However, the mere detection of this colossal object shows that the zone of avoidance may not be as inscrutable as was once thought. Future infrared studies — including potential observations by the James Webb Space Telescope, which has already used its infrared camera to take the deepest image of the universe to date — should further help scientists unlock the hidden secrets beyond the Milky Way's bulge."

 

www.livescience.com...

 

Whenever I read statements like "3 billion light years from earth" and a galaxy cluster "containing hundreds of thousands of galaxies", my brain freezes.

 

Three billion years ago life on earth was mere microorganisms, and one galaxy is too vast for me to comprehend, let alone hundreds of thousands of them.

[Pap]

3 hours ago, Maple Leaf said:

 

Whenever I read statements like "3 billion light years from earth" and a galaxy cluster "containing hundreds of thousands of galaxies", my brain freezes.

 

Three billion years ago life on earth was mere microorganisms, and one galaxy is too vast for me to comprehend, let alone hundreds of thousands of them.

 

The farthest star that you can see with naked eye is V762 in Cassiopeia constellation. It’s 16,308 light years away.

 

1 light year is approx 5.8 trillion miles.

 

Do the maths and try to imagine how far away it is and just how big it must be that we can still see with our own eyes. Mental.

[Cade]

Some stars we see in the sky are probably not there any more.

 

What we're seeing is how they were when the light from them began their journey across the universe and eventually hits your eye. 

 

You're looking at the past.

 

When we see a supernova in the sky, it actually happened many thousands of years ago and we're only just seeing the light from it now.

[JFK-1]

Some nova have been dated precisely using ancient Chinese astronomical records. In 1054 they recorded what they described as a "guest star"

 

A bright star that appeared out of nowhere then remained visible for almost 2 years before fading away. Almost 700 years later someone looked in the reported location of the guest star with a telescope and discovered the crab nebula.

 

A nova would be an impressive sight. A wiki description of a 1006 nova which was sighted and reported in China, Japan, the middle east and Europe.

 

SN 1006 was a supernova that is likely the brightest observed stellar event in recorded history, reaching an estimated −7.5 visual magnitude, and exceeding roughly sixteen times the brightness of Venus.

 

Egyptian astrologer and astronomer Ali ibn Ridwan, writing in a commentary on Ptolemy's Tetrabiblos, stated that the "spectacle was a large circular body, 21⁄2 to 3 times as large as Venus.

 

The sky was shining because of its light. The intensity of its light was a little more than a quarter that of Moon light" (or perhaps "than the light of the Moon when one-quarter illuminated")

 

https://en.wikipedia.org/wiki/SN_1006

 

[JFK-1]

 

Fast Radio Bursts – the mystery that weighs the Universe

 

What’s behind these strange and powerful radio signals from the depths of the Universe? And how do they allow us to weigh the Universe? Astronomer Clancy James is trying to solve the origin of these mysterious signals currently baffling the scientific community.

 

Clancy is a Senior Lecturer at the Curtin University node of the International Centre for Radio Astronomy Research in Perth, Western Australia. This talk was given at a TEDx event using the TED conference format but independently organized by a local community.

 

 

[Cade]

Orion on its way back home.

Earth in the background.
Every single human being is in this picture.

Edited December 6, 2022 by Cade

[JFK-1]

If it's heading back now it beats me why it's going to take so long. I think Sunday is the splashdown date, 5 days from now?

 

The moon averages around 240,000 miles way, but if this craft is going to be coming in at 25,000mph. which it will be, then at that speed you could cover the distance in just 10 hours.

[Cade]

Because space travel doesn't work in straight lines, everything is constantly moving.
Earth itself is travelling at 30 km a second along its orbit path.

 

Orion has performed the return orbit burn, which moved it closer to the moon so it can sling shot around behind it then fling itself towards Earth, which will take until Sunday to complete the journey.

Edited December 6, 2022 by Cade

[JFK-1]

I'm thinking of it from the perspective of having completed their final orbit around the moon and are now pointing Earthwards though still close to the moon.

 

From there I see it as being a straight line towards the Earth because it's right there pretty much filling your horizon. Unlike say aiming for where Mars will be in 9 months when your probe reaches it's orbit, more complex calculation. But still a straight line to that point.

 

I can't envisage how when they have come around the moon they can be any further away than 10 hours or so at 25,000 mph. Straight line to that big thing filling your windows which would be harder to miss than hit since it's not only very big it's actually polling you towards it.

Edited December 8, 2022 by JFK-1

[PortyJambo]

1 hour ago, JFK-1 said:

I'm thinking of it from the perspective of having completed their final orbit around the moon and are now pointing Earthwards though still close to the moon.

 

From there I see it as being a straight line towards the Earth because it's right there pretty much filling your horizon. Unlike say aiming for where Mars will be in 9 months when your probe reaches it's orbit, more complex calculation. But still a straight line to that point.

 

I can't envisage how when they have come around the moon they can be any further away than 10 hours or so at 25,000 mph. Straight line to that big thing filling your windows which would be harder to miss than hit since it's not only very big it's actually polling you towards it.

As the Moon and Earth are both travelling around the Sun, so aren't stationary, think of two cars travelling down a road but separated by some distance.

 

If you were somehow going to jump from one to another, you can't just jump in a straight line from one, as the other would be much further down the road before you reached it. You'd have to jump from one and accelerate ahead in a parabolic curve so that you're ahead of the other one and the end of the curve is where it will be by the the time you reach it.

[JFK-1]

16 minutes ago, PortyJambo said:

As the Moon and Earth are both travelling around the Sun, so aren't stationary, think of two cars travelling down a road but separated by some distance.

 

If you were somehow going to jump from one to another, you can't just jump in a straight line from one, as the other would be much further down the road before you reached it. You'd have to jump from one and accelerate ahead in a parabolic curve so that you're ahead of the other one and the end of the curve is where it will be by the the time you reach it.

 

The way I view it the craft also has that same orbital motion around the sun both earth and moon have. It always had it even as it sat on the launch pad and maintained it after leaving the pad.

So from that perspective in my mind this motion becomes irrelevant to the flight of the rocket. It can't be left behind in any way, it's always on that 'road' with earth and moon travelling at exactly the same velocity they are. Around 67,000 mph apparently. As are we.

[hughesie27]

46 minutes ago, JFK-1 said:

 

The way I view it the craft also has that same orbital motion around the sun both earth and moon have. It always had it even as it sat on the launch pad and maintained it after leaving the pad.

So from that perspective in my mind this motion becomes irrelevant to the flight of the rocket. It can't be left behind in any way, it's always on that 'road' with earth and moon travelling at exactly the same velocity they are. Around 67,000 mph apparently. As are we.

You can think that in your mind. But you are wrong.

 

Even planes on earth don't fly in straight lines.

 

On top of the reasons posted above theres also the calculations that will make sure it arrives at the right point of earth to splash down where they want it to.

Edited December 8, 2022 by hughesie27

[Cade]

 

[JFK-1]

16 minutes ago, hughesie27 said:

You can think that in your mind. But you are wrong.

 

Even planes on earth don't fly in straight lines.

 

On top of the reasons posted above theres also the calculations that will make sure it arrives at the right point of earth to splash down where they want it to.

 

I may well be wrong, but i'm being given nothing to convince me. I'm not sure what reasons above you're talking about. Earth/moon orbiting the sun?

 

So is the capsule, always was at exactly the same velocity. If it could be stopped dead on it's current path and given no further instruction it would still have that 67,000 mph orbital motion along with earth and moon. They wouldn't "leave it behind" Would they?

I agree that planes on Earth don't fly in a straight line but they're travelling over a curved surface, i don't see how that can be compared to the spacecraft.

 

And definitely also agree the landing point is a factor, but don't see how that has any great relevance to the return duration. Given all the other complexities of it I would rate that a relatively easy one and entirely unrelated to any earth/moon motion around the sun. 

[Cade]

 

The TLDR is that Artemis/Orion has travelled to the moon along the orange line, has orbited it and it now at the end of the white dotted line, having swung closer to the moon to get a slingshot to build up enough speed to catch up with Earth. 

[hughesie27]

6 minutes ago, JFK-1 said:

 

I may well be wrong, but i'm being given nothing to convince me. I'm not sure what reasons above you're talking about. Earth/moon orbiting the sun?

 

So is the capsule, always was at exactly the same velocity. If it could be stopped dead on it's current path and given no further instruction it would still have that 67,000 mph orbital motion along with earth and moon. They wouldn't "leave it behind" Would they?

I agree that planes on Earth don't fly in a straight line but they're travelling over a curved surface, i don't see how that can be compared to the spacecraft.

 

And definitely also agree the landing point is a factor, but don't see how that has any great relevance to the return duration. Given all the other complexities of it I would rate that a relatively easy one and entirely unrelated to any earth/moon motion around the sun. 

 But it is being propelled at 1000skm/h in addition (or against?) The sun's impact on its velocity. So it's not behaving the same as it would stationary on Earth or floating in space.

You surely don't need anyone on here to prove you wrong. The fact that this is how NASA scientists have decided the trajectory needs to be should be enough!

[JFK-1]

23 minutes ago, hughesie27 said:

 But it is being propelled at 1000skm/h in addition (or against?) The sun's impact on its velocity. So it's not behaving the same as it would stationary on Earth or floating in space.

You surely don't need anyone on here to prove you wrong. The fact that this is how NASA scientists have decided the trajectory needs to be should be enough!

 

I don't know if we're even talking about the same thing here, I watch a lot of NASA stuff and I have never seen anyone discuss what i'm thinking of. Plus you linking it to the orbital motion around the sun, which I see as irrelevant as all 3 bodies have that same motion and velocity right from the get go.

You were suggesting something along the lines of the earth and moon on that orbital path racing away from the craft. I don't see that happening and in fact don't see how that could even be possible.
 

Try it from another starting point, if we were to launch a rocket from the moon directly towards the earth at 25,000 mph, how long do you think it would take to arrive?

[hughesie27]

21 minutes ago, JFK-1 said:

 

Try it from another starting point, if we were to launch a rocket from the moon directly towards the earth at 25,000 mph, how long do you think it would take to arrive?

Just over a day if a constant speed from start to finish. But are you aiming for the earth where it is at takeoff or where it will be in 24 hours time?

In 24 hours after takeoff the earth will be over 1.6million miles away from where it was at take off. So you need to aim for where it WILL be.

 

Also when on the moon or on earth the rocket travels with the planet at its set speed around the sun. They are effectively "attached". Once in deep space the sun's gravitational pull/orbit no longer has the same impact on the infinitely smaller mass of the rocket. So I'd argue that the moon and Earth probably would speed away from it, even if they still all followed roughly the same orbital path around the sun.

 

Edited December 8, 2022 by hughesie27

[JFK-1]

31 minutes ago, hughesie27 said:

Just over a day if a constant speed from start to finish. But are you aiming for the earth where it is at takeoff or where it will be in 24 hours time?

In 24 hours after takeoff the earth will be over 1.6million miles away from where it was at take off. So you need to aim for where it WILL be.

 

Also when on the moon or on earth the rocket travels with the planet at its set speed around the sun. They are effectively "attached". Once in deep space the sun's gravitational pull/orbit no longer has the same impact on the infinitely smaller mass of the rocket. So I'd argue that the moon and Earth probably would speed away from it, even if they still all followed roughly the same orbital path around the sun.

 

 

It took the NASA new horizons probe just 9 hours from launch to pass the moons orbit. And we're definitely not thinking along the same lines here. You keep linking it to earth/moon orbital motion when that can have no significant effect. The earth cannot "speed away"

 

How could you ever catch anything speeding away at 67,000 mph unless you were speeding considerably faster? They all have that motion all of the time.

[hughesie27]

23 minutes ago, JFK-1 said:

 

It took the NASA new horizons probe just 9 hours from launch to pass the moons orbit. And we're definitely not thinking along the same lines here. You keep linking it to earth/moon orbital motion when that can have no significant effect. The earth cannot "speed away"

 

How could you ever catch anything speeding away at 67,000 mph unless you were speeding considerably faster? They all have that motion all of the time.

New Horizons wasn't designed to carry humans. 

You also need to approach the earth from an angle so you can glide through the atmosphere rather than pierce through it and burn up/not be able to slow down sufficiently.

[Fxxx the SPFL]

Space does my head in and apologies i'm sure this has been asked before we are told that it all started with the big bang and that the universe is still expanding away from that. Will it eventually all collapse in on itself and start the whole process again another big bang.

[JFK-1]

45 minutes ago, hughesie27 said:

New Horizons wasn't designed to carry humans. 

You also need to approach the earth from an angle so you can glide through the atmosphere rather than pierce through it and burn up/not be able to slow down sufficiently.

 

A craft not carrying humans is essentially the same thing aside from launch and acceleration. I have watched satellite launches and the only difference was the velocity off the pad for a satellite is comfortably faster, you can't hit humans with that amount of g force.

Artemis launches will also accelerate at a lesser speed for the same reason, but will soon achieve the same speed just taking a bit longer. Not long enough to add hours on to a trip moonward though.

 

When this capsule passes the moon on it's return journey I imagine it will already be travelling almost as fast as it's going to get and will reach the earth every bit as quickly as new horizons reached the moon.

 

Unless there's some massive gradual increase in speed as It approaches due to the gravitational attraction. It may be somewhat like rolling it down a very steep hill.

The approach orientation is of course a factor in re-entry but the way I see it has no relevance to the time it will take to travel from moon to earth. There is no option but to pierce the atmosphere so to speak, there can be no gliding through it which is exactly why it's a fiery hell.

The only real relevance the orientation of the craft itself has is to orient the heatshield precisely for first contact and that's not a big time consuming deal. The approach trajectory itself is about smacking it head on rather than coming at an angle where you might skip off like a stone across water. But neither of these factors in my view have any major effect on journey time from the moon.

My puzzlement about it with a little further digging is I think around it being said a couple of days or so ago Artemis is now on the way home, a week before splashdown.

 

And while that was true, it was on the return leg, they didn't say where it currently was. In fact it was apparently beyond the moon further away from the earth than any craft designed for humans has ever been. 

I think it's something along the lines of it will gain speed on the journey then when it actually does pass the moon and begins effectively a fall towards the earth there will be an end velocity of 25,000mph. 

 

And again I may be wrong about this, but when it passes the moon I expect it will be travelling at close to the top velocity and will reach our atmosphere in little more than 8 to 9 hours from that point. We will see, I expect they will tell us when it passes the moon and actually is on the home straight so to speak 

[JFK-1]

 

The re-entry and splashdown will be broadcast live here.

 

 

[Gizmo]

On 08/12/2022 at 11:12, JFK-1 said:

 

It took the NASA new horizons probe just 9 hours from launch to pass the moons orbit. And we're definitely not thinking along the same lines here. You keep linking it to earth/moon orbital motion when that can have no significant effect. The earth cannot "speed away"

 

How could you ever catch anything speeding away at 67,000 mph unless you were speeding considerably faster? They all have that motion all of the time.

 

 

On 28/11/2022 at 17:22, ri Alban said:

I used to enjoy listening to him and others on The Universe tv series. But him and the other Chinese American, have lost the plot.

Dr Michio Kaku, you mean? An absolute genius. 
 

On 08/12/2022 at 06:19, JFK-1 said:

I'm thinking of it from the perspective of having completed their final orbit around the moon and are now pointing Earthwards though still close to the moon.

 

From there I see it as being a straight line towards the Earth because it's right there pretty much filling your horizon. Unlike say aiming for where Mars will be in 9 months when your probe reaches it's orbit, more complex calculation. But still a straight line to that point.

 

I can't envisage how when they have come around the moon they can be any further away than 10 hours or so at 25,000 mph. Straight line to that big thing filling your windows which would be harder to miss than hit since it's not only very big it's actually polling you towards it.

 

On 08/12/2022 at 10:16, JFK-1 said:

 

I don't know if we're even talking about the same thing here, I watch a lot of NASA stuff and I have never seen anyone discuss what i'm thinking of. Plus you linking it to the orbital motion around the sun, which I see as irrelevant as all 3 bodies have that same motion and velocity right from the get go.

You were suggesting something along the lines of the earth and moon on that orbital path racing away from the craft. I don't see that happening and in fact don't see how that could even be possible.
 

Try it from another starting point, if we were to launch a rocket from the moon directly towards the earth at 25,000 mph, how long do you think it would take to arrive?

Some good thinking on a very complex subject mate but there's a fair bit to unpack here.

The original moonshot was originally devised from several ideas, one which was literally point big rocket at moon and launch. But it's inefficient as you are counteracting the earth's rotation as well as gravity.

It can be done, but you are much better off choosing a free return trajectory which varies dependent on what type of orbit you want to insert the vehicle into when it reaches the moon, ie a low orbit or a high orbit. It takes more Delta-V (total change in velocity) to reach moon orbit and land something on it than it does to do the same on Mars.

Your thoughts on catching up to bodies are in the right ball-park - you do preserve your original velocity in the vector it exists so from earth you will have that sideways or rotational velocity, hence why when a rocket needs to reach the ISS, it just has to raise its orbit to the same altitude and then only go 1 mph faster than the 17, 500 mph the ISS orbits (ok technically free-falls) around the earth, to catch up. It ends up with the same(ish) velocity as the ISS because it's at the same altitude which defines it's orbital velocity. 

That tesla roadster that Space X yeeted into space via the Falcon Heavy escaped earth's gravity, was sent on a Mars trajectory and won't come back to near earth (several million miles) until the 2040s. Our gravitational pull won't always capture stuff into our orbit.  

Artemis is slower than Apollo (3 days) as it has more sustained life support so can take longer and it also targets a different orbit, which is more fuel efficient but takes longer (8 days or something). 

Do you play video games? If so, you can nab Kerbal Space Program pretty cheaply if you want to learn some orbital mechanics and basic rocket stuff (easiest way is to follow Scott Manley or quill18 on the old utube for tutorials). It's bloody amazing though I did crash land on the Mun and I have an astronaut doing a Major Tom in his capsule. I keep meaning to get good enough to go rescue him. 🤭


 

[Cade]

Orion capsule should be splashing down at around 17:30 UTC on Sunday 11th December.

 

Plenty livestreams should be available.

[JFK-1]

Entertaining unusual and I would say somewhat hippy take on the universe and the place of humans in it. Interested me that he said there are 2 trillion galaxies. I had seen that number quoted before but thought it might later have been downsized. But this video is from just 6 months ago so presumably 2 trillion galaxies is up to date.

 

 

[Maple Leaf]

On 08/12/2022 at 07:21, **** the SPFL said:

Space does my head in and apologies i'm sure this has been asked before we are told that it all started with the big bang and that the universe is still expanding away from that. Will it eventually all collapse in on itself and start the whole process again another big bang.

 

The collapse you refer to, once known as "the big crunch", was considered to be one possibility when discussing the future of the universe.  But the expansion seems to be accelerating, so most astrophysicists now believe that the universe will expand forever.

[Gizmo]

6 minutes ago, Maple Leaf said:

 

The collapse you refer to, once known as "the big crunch", was considered to be one possibility when discussing the future of the universe.  But the expansion seems to be accelerating, so most astrophysicists now believe that the universe will expand forever.

Heat death. 😯

[hughesie27]

Livestreams are up just now. 

[Footballfirst]

The re-entry and splashdown seemed to go exactly as planned, but the recovery process seems a bit longer that I would have expected.

 

If there was an emergency situation I would have expected helicopters and fast boats to be on hand within a couple of minutes to secure the craft, if nothing else.

Edited December 11, 2022 by Footballfirst

[Don Dan]

https://news.sky.com/story/nasas-orion-spacecraft-to-splash-back-down-to-earth-after-successful-moon-mission-12766229

[JFK-1]

Looked good. All 11 parachutes deployed in sequence so I guess the heat shield works.

[will-i-am-a-jambo]

8 hours ago, Maple Leaf said:

 

The collapse you refer to, once known as "the big crunch", was considered to be one possibility when discussing the future of the universe.  But the expansion seems to be accelerating, so most astrophysicists now believe that the universe will expand forever.

They reckon that eventually galaxies will be spilt so far apart you won't see the light from them and even the stars within galaxies themselves will get ripped apart and all that will be left will be complete darkness as the last stars die out. Quite depressing thinking about it actually lol 😂

[Maple Leaf]

57 minutes ago, will-i-am-a-jambo said:

They reckon that eventually galaxies will be spilt so far apart you won't see the light from them and even the stars within galaxies themselves will get ripped apart and all that will be left will be complete darkness as the last stars die out. Quite depressing thinking about it actually lol 😂

Yes, I've read that scenario.  The time scales are mind-boggling, iirc, in the trillions of years.  One scientific paper stated with some certainty that, even then, Hibs will still be shite!