Recent Posts

Pages: [1] 2 3 ... 10 Next
1
Space Science Coverage / CMB Cold Spot likely not a super void
« Last post by Star One on Today at 09:44 AM »
It appears that the cold spot found in the CMB data is likely not a super void further study has discovered leaving the door open for more exotic explanations.

Quote
In their new work, the Durham team presented the results of a comprehensive survey of the redshifts of 7,000 galaxies, harvested 300 at a time using a spectrograph deployed on the Anglo-Australian Telescope. From this higher fidelity dataset, Mackenzie and Shanks see no evidence of a supervoid capable of explaining the Cold Spot within the standard theory.

The researchers instead found that the Cold Spot region, before now thought to be underpopulated with galaxies, is split into smaller voids, surrounded by clusters of galaxies. This 'soap bubble' structure is much like the rest of the universe, illustrated in Figure 2 by the visual similarity between the galaxy distributions in the Cold Spot area and a control field elsewhere.

Mackenzie commented: "The voids we have detected cannot explain the Cold Spot under standard cosmology. There is the possibility that some non-standard model could be proposed to link the two in the future but our data place powerful constraints on any attempt to do that."

If there really is no supervoid that can explain the Cold Spot, simulations of the standard model of the universe give odds of 1 in 50 that the Cold Spot arose by chance.

Shanks added: "This means we can't entirely rule out that the Spot is caused by an unlikely fluctuation explained by the standard model. But if that isn't the answer, then there are more exotic explanations.

'Perhaps the most exciting of these is that the Cold Spot was caused by a collision between our universe and another bubble universe. If further, more detailed, analysis of CMB data proves this to be the case then the Cold Spot might be taken as the first evidence for the multiverse - and billions of other universes may exist like our own."

https://m.phys.org/news/2017-04-survey-hints-exotic-cold.html

Here's the paper.

https://arxiv.org/abs/1704.03814
2
That's an interesting revelation re.: the solar magnetic field and its interaction with the galactic magnetic field.

Maybe someone with a better understanding of this field can answer but does this mean that the difference in 'velocities' between the sun and the galactic magnetic field are higher and lower than previously theorised? In either case, what implications would there be for interstellar travel in both technical and flight environment terms? After all, a high-energy interstellar medium could be far more dangerous in terms of high-energy heavy metal nuclei being focussed along the field lines.
3
Hi all
I had a similar idea to the post from Oli some time ago and, after reading the post, I tried to quickly draw it using google scketch-up.
The design is based on re-using MPLMs (4.5m DIA) and Cygnus CPM modules (3m DIA) to have some kind of recurrent design.
Can something like this work? it should fit in the 10m SLS fairing but I am not sure about the "self deploying' mechanism.
Comment are welcome
Cheers

That's very cool! The fact that you could get all that inside a 10m fairing is amazing.

I think that maybe the center section should be 8.4m diameter in order to have commonality of tooling with SLS.

The self-deployment would be tricky, but hey, JWST.
I doubt you can use existing Cygnus as it would be operating under tension. The vehicles are designed for compression loads, there are no tension loads as it currently operates.

I appreciate that, my idea was to use existing tooling. I think PCM structure can be adapted, maybe using an external trellis structure on the outiside. It is not in my drawing but I have also in mind to have solar arrays on the PCM external surfaces, the area would be quite big (something like 3m * 25m * 2). I will try to add it in a future drawing.
And OK, for the 8.4m diam suggestion. I will try to include also that.
4
SpaceX Mars / Re: Red Dragon Discussion Thread (2)
« Last post by Dao Angkan on Today at 09:13 AM »
Probably best to combine it with something like MOXIE which is already compressing atmosphere, filtering the dust, and creating waste heat.

It could be tested in a Mars environmental simulation chamber.
5
Suborbital Missions / Re: North Korea missiles
« Last post by Websorber on Today at 08:46 AM »
A Paradigm Shift in North Korea’s Ballistic Missile Development?

http://38north.org/2017/04/ychang042517/

6
Q&A Section / Re: Thorium Fuel Engine
« Last post by tomakali on Today at 08:00 AM »
ive been tracking the future of transport lately

the uber flying cars, human beings on big quad copters, and terrafugia kind of cars etc
out of all i really like this design

a car without disturbing rotors

but it will be hard for this car engine to lift a bus [public transport]...
so, probably it needs a different kind of engine

as the human population is exploding. it would be great if someone could comeup with an idea for
a flying bus, or a flying train or a flying ship which can land/takeoff from the beaches/sea/lakes/rivers etc


imagine a swarm of flying cars overhead  :-[
it would be better if there are few flying objects over my head
7
Can crystal growth or purification of certain materials be done on a vomit comet? Will pharmaceutical companies be willing to pay for or invest in the technology to develop crystals.

I did X-ray crystallography in my honours (4th year) project - working on the androgen receptor (for prostate cancer).  It can take a few days to a few weeks to grow a good sized protein crystal, so no, the vomit comet is no good for this.

According to wikipedia (and with what I've heard, I believe it) pharmaceutical companies usually spend north of $1 billion in R&D per drug that they are able to bring to market, and the crystal growth process (for hundreds/thousands of candidates) is a large part of that.  Very labour intensive.  My impression/gut feeling has always been that launch costs won't have to come much down at all for this application to make financial sense - it's more the logistics of having a dedicated space station.

As I mentioned upthread, crystal growth is extremely sensitive to vibration.  Even our small university lab had a separate crystal growth room with sound-proofed walls/windows.  The reason for a dedicated low-vibration space station is resolution.  A mediocre crystal with some flaws (due to bumps) might give a resolution of 4-5 angstroms, where as one grown under ideal conditions could give a resolution of <2 angstroms.  That resolution is everything in drug design.  At the end of my project my best crystal had a resolution of 3.9A if I remember correctly - good for a student but not really good enough to do anything with - the phd student in my lab had one that resolved to 1.8A, and he got a paper out of that :) 

Getting sub 1 angstrom resolutions consistently would be the holy grail (which should be possible in zero-g), so yeah I'm quite sure there's a market for dedicated space stations for pharmaceutical companies. However I can't imagine the tourists will want to sit in silence without moving for their whole holidays ;D so dedicated is the word.

Do you know if there are any organisations out there with the experience of building the required equipment, that have the funds and/or would be interested in cooperating with companies like Bigelow to develop space stations that have the required low vibration? Vibration on a 'standard' space station isn't negligable.

Not sure.  I know they are doing some protein crystal growth on the ISS, but I haven't heard whether these have generated better results (or even results as good as) than results generated in the best Earth labs.  I did hear that the reason centrifugal experiments for the ISS usually cite for cancellation is the need for low vibration environment required by the protein crystal growth experiments.

The actual analysis of the crystals is done on an X-ray Synchrotron (these are CERN or similar institutions with particle accelerators), and taking a particle accelerator to space is not an option, so the crystals have to go through re-entry before they can be analysed.  Not sure whether that's also an issue.
8
Q&A Section / Re: Thorium Fuel Engine
« Last post by ChrisWilson68 on Today at 07:49 AM »
got it

so,
what are the better[cheaper and efficient] fuel for a flying bus or an Iron man suite?
which could be the best fit for this specific purpose?

How do you define "flying bus"?

Depending on your definition, you might say a Bombardier CRJ700 jet is the closest thing we can get to a flying bus with current technology.  It runs on kerosene.  Or, if you define it as something that doesn't need a runway, then maybe the CH-47 Chinook helicopter is the closest thing with can get to a flying bus with current technology.  It runs on kerosene too.

If you want something like what you see in Back to the Future, that looks like a road vehicle but can hover without any wings or rotors, you're going to be disappointed.  We don't have the technology for that, or anything on the horizon that could give us that.

The Iron Man suit is also not anywhere close to being realistic with our current technology or any currently-forseeable technology.
9
Q&A Section / Re: Thorium Fuel Engine
« Last post by tomakali on Today at 07:37 AM »
got it

so,
what are the better[cheaper and efficient] fuel for a flying bus or an Iron man suite?
which could be the best fit for this specific purpose?

10
Q&A Section / Re: Thorium Fuel Engine
« Last post by ChrisWilson68 on Today at 07:34 AM »
ok, im a noob in space tech...
just out of my curiosity

what are the better[cheaper and efficient] fuel than thorium? [for a flying bus or an Iron man suite]
to be able to fly without propellers and less noise/pollution

Thorium isn't going to power a flying bus or Iron Man suit in the foreseeable future.  Neither is anything else.

Thorium goes in nuclear reactors that are very similar to all the nuclear reactors we currently use in electrical power plants, aircraft carriers, and submarines.

As to what is better/cheaper, the answer is uranium and plutonium.  That's why we use uranium or plutonium in nearly all reactors in use today.

The people who design reactors aren't dumb.  There's a reason we've been using uranium and plutonium for decades.  It's not because people didn't know thorium existed.  It's because they looked at the trade-offs and decided uranium and plutonium were the better choices.

You can start with the Wikipedia article for some advantages and disadvantages of thorium versus uranium and plutonium:

https://en.wikipedia.org/wiki/Thorium_fuel_cycle
Pages: [1] 2 3 ... 10 Next