saac

35 minutes ago, Stuart1971 said:

We need to worry about here and now not a few decades in time, they way things are going there won’t be decades in time….😮☹️

Again, why can't we do both?   I guarantee you that the technologies that are being developed now in programs like SpaceX, the engineers that are gaining experience, will all be making positive contributions to other problems in other fields now. Science and technology never develops isolated in stovepipes, gains in one field cross fertilise into others.  Musk's business model of fail fast and learn for example has already been mimicked by a number of fusion start-up companies.  The solutions to climate change, plastic pollution, water stress, food production are not going to appear in short order but will emerge over decades. 

Jim 

19 minutes ago, Stuart1971 said:

Very true, and I don’t have the answer, but what benefit to 99.9999% of the people on this earth, is getting a big rocket into space going to have, absolutely none whatsoever, an absolute pointless task, but he has the money to waste…at least his starlink venture was helping many people, as much as it’s a pain for us astrophotographers….but this latest stuff, is a case of “Boys and there toys”

Why can't we do both?  Who knows what may come from from this technology?  Fast forward a few decades and we may well find we are in an age of mining of materials extra terrestrial.  Appropriately so called "rare earth" metals essential for a whole host of technologies and which are certain to play a key role in our future energy generation  (fusion, solar etc) are the prize.  I can't remember who said it, Brain Cox perhaps,  "these technologies (SpaceX etc) will allow us to move damaging, heavy polluting  industrial activity off our fragile Earth. 

As for Starlink, yes I do agree with you there, the gain seems frivolous compared to the damage done.  

Jim 

8 hours ago, Shimrod said:

As you say there's a variety of approaches to astronomy and as long as someone is having fun, then does it matter how they observe.

My personal challenge with these devices is understanding why I would use one of these over looking at pictures from the internet. Putting visual to one side, I would suspect that the challenge of capturing the images forms a big part of the enjoyment in AP.

Yep I think that is it, being actively engaged in the process rather than looking on the internet which is more passive. This type of system, for the price, would be ideal for small outreach and social events. 

Jim 

That is very nice indeed, very nice. Well done.

Jim 

The 20 outer rings as mentioned by @DaveS are fixed, gimble hydraulics for these were apparently removed to save weight. The remaining engines appear to be gimbled. 

Jim 

5 minutes ago, 900SL said:

 

 

How do they compensate for the off axis thrust? Are the engines independently gimballed / throttled ?

I believe all of the engines on the Heavy Lift rocket are independently gimbled - need to confirm for certain but pretty sure that is the case.  

Jim 

13 minutes ago, 900SL said:

I am struggling to see how having 33 separate engines (with all the associated plumbing, hydraulics and wiring) is a beneficial design. To this simple Engineer, it seems like multiple potential points of failure

 

What happened to KISS??

Sometimes having 33 separate engines is KISS, bear in mind this system is producing twice the trust of the Saturn 5 rocket.  More points of failure sure, but it also brings multiple redundancies. 

Jim 

13 minutes ago, DaveS said:

I don't know how detailed the telemetry is. For all I know each engine may have been monitored to the last degree.

Telemetry provides performance parameters (pressure, flow rate, temperature, position and displacement etc) it doesn't provide failure mode for that you need to get the physical component for onward analysis. Think of aircraft accident investigation; where they can, they recover as much of the aircraft structure and components as possible for analysis.  Anyway, they know what they are doing and will be all over it. 

Jim 

2 hours ago, DaveS said:

Telemetry data would be good. I could see 6 Raptors out before the bang, and could see some flaming out (Or exploding) during the launch. Given that SpaceX reckon that they need 31 running to reach orbit, this was never going to proceed. Guess they ran it as long as they did to gather as much data as they could.

It certainly is but it will tell next to nothing about the nature of component failure. Here's hoping they are able to recover as much of the hardware as possible. 

Jim 

14 minutes ago, DaveS said:

Mutterings that I've heard talk about another launch in August. Booster 9 and Ship 26 are pretty much ready. SpaceX will learn a lot from this test.

One would hope, I wonder if they will get anything beyond telemetry data!

Jim 

Definitely faked - CGI I think  

make the most of it Paz, enjoy.

Jim 

Andrew's extract from Blake's "Auguries of Innocence" got me reflecting on a related (tangent) theme from a favourite 1950 science fiction B movie "The Incredible Shrinking Man".  The central character in the movie is caught in a mysterious mist which, over the following weeks, causes him to shrink in size. In the closing scene, he has shrunk to such a diminutive size that he is lost from the sight of his family.  Alone in the basement of his house, having fought of the resident spiders and assorted bugs, he continues to shrink even further, presumably destined to enter the realm of microbes and then beyond.  Having now lost everything, with an uncertain future ahead, he questions his own humanity. In the very final scene, his view turns skyward through a window in the cellar and his gaze falls on the night sky and the stars in the heavens above.  For all that his future places him beyond humanity, the life and world that he once knew, he considers how the view of the night sky and his relation to the stars above is the only thing that has remained unchanged to him.  The scale of the universe is as infinite to him now and will be in his future as it was before.   For me that is what Blake means when he says "to see the world in a grain of sand, to hold infinity in the palm of your hand ".  To answer the OP's question then; the numbers we place on the size of the universe are from a practical view largely irrelevant, its scale is lost to our common understanding. 

Jim 

15 minutes ago, andrew s said:

I like this from William Blake:

"To see a World in a Grain of Sand And a Heaven in a Wild Flower, Hold Infinity in the palm of your hand And Eternity in an hour."

Regards Andrew 

One of my favourites. 

Jim 

In the future, prices for all astrophotography related equipment will fall to normal pre "how much!"  levels.

Yeah, that is not going to happen , I'm betting on Elon Musk's Clear View constellation.   

Jim 

Elon Musk will offer to put your telescope into orbit in his new Clear View Sky Train satellite constellation. You know, the one that sits in a higher orbit than his original Sky Train constellation that trashed the night sky view for everybody.  

AI post processing software - two levels of service

- do everything - lets you upload your files as captured and produces optimised image, saves time which you can use to sleep, drink whisky.

- take me by the hand - analyses your data then offers step by step guide like an expert on your shoulder; saves time which you can use to sleep, drink more whisky.

Jim

That is so cool to be from a phone camera. Well done, great effort.  
 

Jim 

57 minutes ago, ollypenrice said:

Excellent!  I have a cubic metre of nothing and I find another cubic metre of nothing. Do I need two cubic metres of space in which to contain them? Or will they both fit into no cubic metres of nothing?

lly

Just don't expect to fly Ryanair with them without paying for overhead storage.

Jim

ps - my engineering head cannot fail to comment that you have over specified your container - most inefficient use of material  

7 hours ago, andrew s said:

Lets keep it simple. Following Einstein,  time is what a clock measure and keeps everything  from happening  at once. Space is what a rulers measure and stops everything being in the same place.

No clock no time, no ruler no space and no clocks or rulers no space time.

Regards Andrew 

I will refrain from trying to debunk the misunderstanding about light, photons and time etc. Life is too short and I have flies to catch using the Mr Miyagi chop stick method.

I couldn't resist, courtesy of ChatGPT :  

Jim

In spacetime's fabric, light does race, 
At constant speed, it keeps its pace,
Its world line traced in null event's space, 
No time to feel, no moment to embrace.

Null trajectories, world lines traced,
In spacetime's fabric, they are based,
A path through which light is raced,
And cosmic mysteries are faced.

No time to feel, no moment lost,
In timeless flight, no matter the cost,
Null events are where they are crossed,
And in their wake, we're left engrossed.
 

Here is something:

Scientific American - Endless Creation Out Of Nothing

Perhaps it not only exists but it was necessary in order for the universe to appear.

Jim

Maybe nothing can exist but it is temporal, existing for the fleeting moment between the transient fluctuations of the quantum field and appearance/disappearance of virtual particles  

Jim

15 minutes ago, andrew s said:

Energy can be negative depending on where you decide to put the zero point. For gravity its typically set at zero an infinite distance from a mass. If you have a test mass at infinity and move it towards a real mass it gains negative energy!

However,  energy is bounded from below as if not atoms would not be stable and we would be nothingness.

Regards Andrew 

This allows us to define gravitational potential as the work done to move a unit mass (test mass) from infinity to a particular point from the planet. The gravitational potential (V) at that point given by  V = - GM/r . The negative sign often causes confusion with students when we use this in the work up to escape velocity. They are used to the more familiar expression of gravitational potential first introduced as Ep = mgh.  But with Ep = mgh we have created an artificial zero point (reference point) of the Earth's surface and h becomes the height above Earth's surface. 

An easy path for students  to consider the negative term is to think about the work done moving a mass (m1) away from a second mass (m2). This requires an increasing amount of work to overcome the attractive force between the two masses. However the gravitational potential energy must increase towards zero at infinity  - it must therefore have been negative at all points in between   I think a similar convention is at play with electron energy levels (Bhor model) where the ionisation level is taken as the zero reference and levels below appear as negative.  It's a convention that can lead to confusion in exams, examination bodies not always sympathetic to ignoring signs when calculating differences between energy levels.  Poor student , Physics can be pedantic at times. 

Jim

Beautiful. Never seen Bodes and the Cigar in widefield before, looks great. 

Jim 

We been looking at this all wrong, it exists and here is what it looks like  

One of my favourite cartoons and so redolent of the long hot summer days of youth occupied with hours of doing nothing.

Jim

40 minutes ago, 900SL said:

A lot of modern physics sounds like nonsense, it has to be said.

 

Virtual this, imaginary that, negative energy etc. I know this fits the observations, but my guess is somebody is having a right laugh here.

That's because like me you are an engineer and as we know engineers are too short to see over the fence like physicists who are of course taller.  

Jim 

What does nothing look like ?

The OPs input since asking the question?

Jim