Starship Asterisk*

If this object is also rotating with the same angular momentum as the Earth in the same direction (the opposite of two meshed gears that rotate in opposite directions), it will exactly stop the Earth's rotation. Not just the amount of energy needs to be the same, the alignment of the axes of rotati...

G'day Henning, First of all: Welcome on this forum. I forgot to say that in my first reply. ... a Newtonian calculation should give errors on the order of unity, purely from dimensional considerations. I was aware of the fact that the Newtonian approximation is not correct. When pressed for an aswer...

G'day Henning, It is not the strength of gravity per se that tears stuff apart (and by the way, gravitational strength is not easily definable in non-Newtonian territory such as black holes), but tidal forces, i.e. spatial variation of gravity. That doesn't have to be very large at the horizon, e.g....

Plutonian wrote: Would somebody be kind enough to refer me to one of those images?

http://antwrp.gsfc.nasa.gov/apod/ap080706.html

The Messenger site says the MDIS instrument covers a range from 395 nm to 1040 nm. Visible light is about 400 to 750 nm, so about half of the filters are probably visible light, and it doesn't go very far into the infrared. It wouldn't really be considered a thermal image, as thermal radiation is g...

Imagine the force it would take to stop the Earth from rotating. It would probably have to collide with something big. Going against the grain of rotation; no less. Lets start with the rotational energy of the earth. E = ½ I ω² where E is the energy, I is the moment of inertia and ω is the circle f...

Was wondering what kind of forces work on hula hoops, and was gonna ask here, but found this quick explanation online: Three remarks: The expression for Ff in Fn and µ is a formula for the maximum friction force. At any moment in time the actual friction can be lower than the product of µ and Fn. T...

Differences in temperature can cause turbulence resulting in pressure and density variables. I partially agree. A consequence of turbulence are fluctuations in pressure and thus density. Differences in temperature cause a mass flow from warm to cold. That does not necessarily have to mean that the ...

Makes sense that you'd need the mass first before the condensing to stars occured. But the difference between Mass and Gravity needs to be explained to my little head. Mass deforms the space-time fabric. We experience the deformation (we tumble into the deformation) and call it a gravitational forc...

The polar grid overlayed on the image is confusing because it confounds following the arms and it isn't centered on the galactic center. I was starting to think it was some ridiculous artistic touch to make the image look more technical. However, looking at the big image, I finally realized it was ...

Usually, the more I read the more I understand. With some of the posts in this topic, the more I read the less I understand. The subject was a phrase i learned in ancient Greek and it is rather appropriate when you encounter Quantum Mechanics. The world of QM is so alien, that our brains are not tr...

Exactly, so some parts of the far side should be visible. Lacking that, there may not be a far side. Correct. In an earlier comment i pointed out that -although not impossible- it is rather unlikely that the alignment is exactly edge on. Since this type of explosions is not uncommon, at least there...

"And I would put you and this forum in the {non-commercial} category." resp. "I have the same opinion on this as Case" Thanks for you point of view. When legal issues are on my path, i feel unpleasantly itchy. The Chandra page said the stars were added from AAO2. You might be ab...

It looks as if the bluish outer area is tilted up on the right and down on the left with respect to the brighter inner half of the disk which appears more horizontal. Indeed, agreed. The center looks like a huge ball, which sagged through the ice and is now partially floating on water. I notice ano...

Glad I could cause you more work! Well, that does not matter, its hobby, the last A in JAA (just an amateur). As the subject reads, i have a legal question and i'm not very good in legal questions. I would appreciate some help. On http://chandra.harvard.edu/photo/image_use.html it is reported: <<Qu...

"The arm is labeled in this illustration as the Far 3kpc Arm, located at a distance of 3 kpc (kiloparsecs) or about 10,000 light-years from the galactic center, on the opposite side from the Sun." How can there be an OPPOSITE SIDE to Sun. What is meant: the arm is at the side of the galac...

Interesting analysis, Henk. I was wondering if you recreated the RGB from the composite picture, or did you use the originals (see http://chandra.harvard.edu/photo/2008/sn1006c/more.html ). Unfortunatedly the first: i used the larger image under the APOD, which is a combined image. The images at Ch...

Something that's bothered me recently about the black hole information paradox: why is it a paradox at all? Due to relativity, from the point of view of a distant observer nothing ever actually falls into a black hole in the first place, but rather objects approach asymptotically close to the event...

I don't know anything about large hypothetical " relatively dense regions of interstellar material " but two things we certainly can surmise about about an expanding Ia supernova explosion: 1) It will quickly impact a large companion giant star that is blocking almost one entire hemispher...

G'day folks, "Conservation of Information" is, I think, a consequence of quantum field theory, but I only have the most basic of layperson's understanding of anything quantum-mechanical. In the meanwhile i learned that there are two laws of conservation of information. One is adopted by re...

G'day Kovil, I was seeing Inertia (by which I mean Momentum also, and the rotating I spoke of was meant as angular momentum) as being the conglomerate angular momentum of everything inside of the event horizon. Ahh, now i see. The sum of all rotations of particles leads to some sort of axis, which i...

Here's how my understanding goes, and it begins with the Hawking idea that space and time trade properties upon crossing the event horizon: Space becomes 'time like' and time becomes 'space like', I'm trying to understand what you mean, since it is not entirely clear to me, even after reading your ...

I notice that the debris cloud limb looks flattened/oblate at the point of the brightened yellow/white line and wondered if this is because the matter which is causing the brightness in the limb is also slowing the shock front down a little, resulting in the flattened edge at this point? Right! A s...

Unless we're "inside" the black holeNoel Would you prefer a universe populated with electrons and anti-protons? You know, for me, that would simplify a lot. If our universe is within a black hole, no expansion of the spacetime fabric is needed to explain the red shift. The closer a galaxy...

G'day Arramon, You had questions, like Justin Hayward of the Moody Blues. A different kind of questions. And being in space for so long, would we be looking at evolution from radiation? mutations? Would humans produce, grow and mature differently in space than they would on earth? Especially over va...