James Webb Telescope

[Darat]

I wondered whether some kind of shields are possible, but I don’t know if they are. At least those like you see in Star Trek. Physical shields would add a lot of weight but maybe they are the only realistic idea. And would even those be eroded away during the journey.

The only possibility for such shields would be magnetic, there was a fad for Bussard ramscoop spacecrafts in science fiction - Niven and Pournelle often used the idea. They would say the immense electro-magnetic fields that scooped up the interstellar hydrogen also acted as a form of shielding. (If I remember correctly further work on the likes of the Bussard ramjet idea showed they wouldn’t work or produce so little acceleration that it would take a million years or so to get up to earth scale speeds.)

 

[theprestige]

I wondered whether some kind of shields are possible, but I don’t know if they are. At least those like you see in Star Trek. Physical shields would add a lot of weight but maybe they are the only realistic idea. And would even those be eroded away during the journey.

It's always going to be physical shields. Please, think this through with basic scientific reasoning and skepticism.

The mass-energy to stop a bullet is thus-and-so, if it is primarily mass. If it's going to be primarily energy, how much energy do think it takes to replace the equivalent mass of physical armor? How much do you think the generators for that energy will weigh? How much fuel do you think those generators consume per second, to replicate the effects of the equivalent mass?

 

[Puppycow]

It's always going to be physical shields. Please, think this through with basic scientific reasoning and skepticism.

The mass-energy to stop a bullet is thus-and-so, if it is primarily mass. If it's going to be primarily energy, how much energy do think it takes to replace the equivalent mass of physical armor? How much do you think the generators for that energy will weigh? How much fuel do you think those generators consume per second, to replicate the effects of the equivalent mass?

I think you are right. I'm not trying to argue the opposite of what you say. Only leaving open the possibility that maybe there is some sort of way that I don't understand.

 

[Puppycow]

Back on topic, here is Dr. Becky’s latest video about what she is anticipating in the first batch of images to be revealed on Sunday.

https://youtube.com/watch?v=sNJR3lenz1I

 

[Darat]

Does she say it will be "We apologise for the inconvenience"?

 

[shemp]

It'll be nothing but kitten pics.

 

[Puppycow]

I had total brain fart.

The NASA announcement said July 12, and I read it as June 12. It's going to be another month before these pictures come out.

 

[gerdbonk]

I had total brain fart.

The NASA announcement said July 12, and I read it as June 12. It's going to be another month before these pictures come out.

What?!

I demand an investigation!

 

[rjh01]

This is a very good youtube from Anton Petrov about the Meteoroid and related topics. It discusses several things not mentioned elsewhere, such as collisions with other satellites such as Hubble and the ISS.

 

[Puppycow]

Good video. And here's one from Launch Pad Astronomy.



"Tis but a scratch!"

 

[arthwollipot]

NASA scientists say images from the Webb telescope nearly brought them to tears

Six months have passed since a European rocket lofted the James Webb Space Telescope into orbit. Since that time, the ultra-complex telescope has successfully unfolded its expansive sunshield, commissioned its science instruments, and reached an observation point more than 1 million km from Earth.

This white-knuckle period in space followed nearly two decades of effort to design, build, and test the telescope on Earth prior to its launch on Christmas Day, 2021. But now, all of that effort is in the rearview mirror, and Webb's massive 6.5-meter diameter mirror is gazing outward and collecting scientific data and images. It is the largest and most powerful telescope that humans have ever put into space, and it's already revealing new insights about our cosmos.

"The images are being taken right now," said Thomas Zurbuchen, who leads NASA's scientific programs, during a news conference on Wednesday. "There is already some amazing science in the can, and some others are yet to be taken as we go forward. We are in the middle of getting the history-making data down."

...

The telescope is healthy.

That's all I need to hear. I've waited twenty years for this. I can wait a couple of weeks more.

 

[Puppycow]

Well, here we are in July. Almost there.

I see that most of the instrument modes (15/17) have been calibrated/commissioned.

https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html

The temperatures don't appear to have changed much at all in the last two months.

 

[Samson]

I wonder if we get an update of the original Hubble deep field image?

 

[Puppycow]

I wonder if we get an update of the original Hubble deep field image?

Probably. NASA isn't saying exactly what they have, but I would suspect they would do that.

Here's Dr. Becky's recent video:



You can see that at the longer wavelengths, like 26 micrometers, there's a bit of noise from latent heat on the primary mirrors.

 

[arthwollipot]

Dr Becky has an infectious enthusiasm.

 

[jonesdave116]

Dr Becky has an infectious enthusiasm.

Yes. I'm rather fond of her! Her and Alice Roberts in the same............. nah, let's not go there!

 

[Gord_in_Toronto]

NASA scientists say images from the Webb telescope nearly brought them to tears

That's all I need to hear. I've waited twenty years for this. I can wait a couple of weeks more.

Similar article here:
https://www.digitalcameraworld.com/...e-so-beautiful-they-bring-scientists-to-tears

Nice comparison shots between Spitzer and Webb.

 

[Reformed Offlian]

Side note: that may look at first blush like it’s got 3 digit of accuracy, but it doesn’t. That’s just 0.001 inches, converted to metric. So it’s got barely 1 digit of accuracy.

So is this one of those "37 degrees Celsius becomes 98.6 Fahrenheit" situations?

 

[Puppycow]

One more week

 

[Ziggurat]

So is this one of those "37 degrees Celsius becomes 98.6 Fahrenheit" situations?

Even worse than that, because even before conversion the 0.001 inches is really only a ballpark figure, with actual thicknesses varying a lot more than body temperature does.