Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Comments

top

Mysterious Feature Appears and Disappears In a Sea On Titan

ihtoit Re:subsurface terrain & tides (65 comments)

The eccentricity of the orbit does not need to be high, but because a tidally locked body tends to circularize its orbit, you need another moon or body that sustains the orbital eccentricity. Saturn has several dozen moons.

So what happens then is that as the body comes closer to the primary, it gets stretched more due to gravitational gradient and when it orbits further away, it reshapes itself to more closely resemble a sphere.

Io's crust raises and drops about 100 meters as it orbits around Jupiter. Its eccentricity is sustained by a 1:2:4 resonance with Europa and Callisto and is tidally locked with Jupiter.

If you think of tides as rising and falling surface, then yes, a tidally locked body can have tides.

As Titan is also in an eccentric orbit, the tidal influence pulls the moon into weird contortions - those tides are between 60 and 96 times stronger than Luna's influence on Earth. There will also be a bulge which moves, considering the orbital speed which changes constantly and the rotation which is constant, the net visual effect from Titan's surface is that Saturn librates. From the surface of Saturn (stick with me), we see way more of Titan's surface than we would if it were in a perfectly circular orbit. ALSO: consider Titan's atmosphere, which is half again the density of Earth's. All that fluid will be even more affected by tides, as will any liquid bodies such as seas of methane - no matter how fairly static those tidal influences, they are still moving, and moving against a superrotating atmosphere.

3 hours ago
top

Are the World's Religions Ready For ET?

ihtoit Re:Are scientists ready? (480 comments)

there's apparently no reason why life can't be silicon based. We would be in trouble though, as it would be completely toxic to us. The decider was pretty much on the relative abundance of silicon and carbon.

4 hours ago
top

Are the World's Religions Ready For ET?

ihtoit Re:Can we even detect ourselves from beyond LEO? (480 comments)

both. Probably why it came back inconclusive - certainly there was trace of organic chemistry, but whether it was intelligent, Voyager couldn't determine. I think Sagan mentions it in "Cosmos", in the same bit as his "Pale Blue Dot".

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:ET would disprove God (480 comments)

the Bible doesn't say anything about us blowing up cities with nuclear fire either -didn't stop us from doing it twice.

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:Aliens = God? (480 comments)

uh... because we are outdoor creatures, and outdoors is where white skin doesn't do so well. Which is why we ordinarily tan, but coupled with lifestyle our diets don't equip us with the requisite raw materials to synthesise enough melanin to cope with solar radiation - and slapping on UV block isn't doing you any favours. Incidentally, the 25-hour circadian rhythm myth is just that - a myth. The experiment was faulty in that it failed to isolate the test subjects from artificial light (which they were allowed to control hence throw the experiment by artificially delaying their internal clocks).

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:Are scientists ready? (480 comments)

Silicon based life? (ref: David Darling)
Germanium? (ref: Sagan)
How about tin? (can we hear some L. Frank Baum, here, the only example of tin based life in literature I can think of)
Lead?
Flerovium?
Ununquadium?

(OK, the last three are extremely unlikely given the low reactivity of lead and the short half lives of flerovium (half a millisecond) and ununquadium (2-30 seconds?) coupled with their inability to form a tetrafluoride (which is apparently kind of important in organic chemistry)

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:Paging Arthur C. Clarke... (480 comments)

oh dear, except angels are extracorporeal for the first point, and for the second they're not allowed to interact with any of God's creations. Nothing stopping aliens from interacting with any of God's creations, but that itself would open up a whole new mess - like, what happened to giving Man dominion over all he surveys (Genesis 26, Psalm 8)? How can you hold dominion over something which is demonstrably superior to you in every way?

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:If ET shows up proselytizing (480 comments)

...that's providing you survive the wonderful new diseases they've brought with them.

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:ET would disprove God (480 comments)

read it again: when God created Man he gave him dominion over ALL THINGS. Including aliens.

If that is an acceptable premise, then God lied to Man if he made aliens superior to Man to the point where a guy in a rubber suit and a torch for a finger lands in the middle of Central Park using a propulsion system nobody on this planet has even conceived of.

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:ET would disprove God (480 comments)

uh... angels don't live among us nor do they interact with any other of God's creations - they're not allowed to. Your point is invalid.

yesterday
top

Mysterious Feature Appears and Disappears In a Sea On Titan

ihtoit subsurface terrain & tides (65 comments)

we have it on Earth: sea terrain that's only visible at low tide - think sandbars to mountain ranges. The Mid Atlantic Ridge is the prime example of the latter (some islands submerge during high tide), the only example I can think of of a semi-permanent sandbar feature is Dogger Bank in the North Sea which during storm surges has been known to exposure to the air from several dozen feet down. Don't forget also that Titan orbits a primary that's quite a bit more massive than Earth and is itself twice as massive as Luna. Tidal effects will necessarily be more pronounced.

yesterday
top

Are the World's Religions Ready For ET?

ihtoit Re:ET would disprove God (480 comments)

Why, Christianity, of course.

A few passages to whet your appetite for knowledge:

You made them rulers over the works of your hands; you put everything under their feet - Psalms 8:6
And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth. - Genesis 1:26 (KJV)

Commentary: when God created Man in His own image, he didn't just do it for appearance's sake, he made Man to be one step below the Angels, to be gifted with a body that could interact with his great creation (Earth), but he hobbled them - he didn't give Man the one thing that would have (and did) made Man imperfect: free will. That was defeated by the simple expedient of a woman, a serpent and temptation, and described in a footnote.

Given the passage from Psalm 8, it would follow that aliens were created by God hence being beneath Man-"Dominion over all things"-Kind hence would lag permanently behind us technologically. It follows, therefore, that either God lied or aliens were not created by God but by someone else and landed here for the simple purpose of extending dominion over us.

yesterday
top

The Physics of Space Battles

ihtoit Re: Umm no (446 comments)

oh, consider (and I'll vastly simplify the math here):

A bullet weighs 1kg
The gun weighs 1000kg (not counting mass of ammo)
The gun is moving in a prograde direction (in the direction the barrel is facing) at 1,000m/s

The gun fires 1000 bullets each at 1000m/s muzzle velocity

Each bullet pushes back on the gun with an equal force to that which ejected it (1000m/s of delta v divided by 1) in the opposite direction (1000m/s divided by 1000).
Those thousand bullets push back on the gun with a combined total of 1,000,000m/s of delta v, divided by the mass of the gun (1,000kg) which gives 1,000m/s.

The gun *stops*.

The A10 Warthog is moving at 165m/s in a typical attack dive. That's about 370mph. When it fires its slugs from its .69kg cartridges (it doesn't send the brass, it polices that and dumps it back into the magazine rack so what it's firing is necessarily lighter and moving a LOT faster than it would if it were firing the entire cartridge), it's firing them out with sufficient force in fifty rounds to stop 23 tonnes (fully loaded) of airframe in midair. The thing ain't subtle.

yesterday
top

The Physics of Space Battles

ihtoit Re: Umm no (446 comments)

alternatively, you could just hang around a bombing range and watch as the A10s rip dead tanks to shreds. Off the coast of Lincolnshire there's just such an air range (it's actually on a tidal marsh) where A10s go into vertical dives, all you hear is a "BRAP!" and that was fifty rounds each the size of a milk bottle - and the aircraft, if you spot it before it goes for a pullout, is literally just hanging there with its arse pointing toward space. From a 400mph dive, it's sitting still with smoke pouring out of the cannon. I used to spend many an idle hour just watching these things, it was poetry in destruction. Eventually got to the point where I could spot them on pass approaches long before they started their attack dives.

And yes, they are full throttle when they fire those cannons.

A satellite would have similar problem particularly if it's firing prograde or retrograde. Firing prograde would slow it down and it would fall out of orbit, firing retrograde it would speed up and possibly achieve escape, so the ideal is to have a heavy satellite (as heavy as you can get away with and still be able to gimbal the entire vehicle) and light ammunition (OK, this is a satellite in orbit, which will making replenishment awkward if not very difficult, so you want your ammunition to be as light as possible but still be confident in its effectiveness - and for a spray and pray, in space, all you really need is something carrying enough kinetic energy to puncture a pressurised tank/hull, and for that and considering there's no air to slow it down during flight, you can get away with firing a cloud of ball bearings and Kessler the fucker to death. Just don't be there on the next orbital rendezvous with your new Death Cloud).

yesterday
top

Are the World's Religions Ready For ET?

ihtoit ET would disprove God (480 comments)

I thought that might grab your attention - practising religious or not (I am not. Disclosure: I am a nihilistic fatalist agnostic and proud), it is a very controversial statement to make. What I'm about to follow that with is probably nowhere near, but still, controversial.

According to the one religion I'm somewhat familiar with, and possibly others as well, humans are the most intelligent (on a sliding scale) form of life in the Universe (not counting the monotheistic God who is apparently omniscient and omnipotent which would give him an unfair advantage). Were that the case, and considering God gave Man ultimate domain over all he surveyed, then any alien landing on this rock would automatically become the property of the first human who set across it. I believe that any alien intelligent enough and technologically advanced enough to actually make the journey is immediately and demonstrably superior to us in every way, putting Mankind in defiance of God and itself in danger of being instantly rendered vapours by a jealous deity - who would then set to making any who saw it either forget or drop dead/spontaneously combust/lose the faculty to speak or otherwise articulate thought. Either way, said alien would not take kindly to being abducted and probed (I'm sure he would have his own equipment for that), and would be equipped with the ability (and will?) to defend himself and his honour with all manner of weaponry or even turn that spanky engine of his into some exotic bomb capable of reducing the entire solar system to ash.

(It's what I'd do).

yesterday
top

Why did Microsoft skip Windows 9?

ihtoit Re:They're 2 for 3! (199 comments)

Re: your .sig: agreed, or we could out of spite start using Unicode notation >:]

yesterday

Submissions

top

Leon's Law: Police Cam Pilot Commences In London

ihtoit ihtoit writes  |  about 8 months ago

ihtoit (3393327) writes "Following the death of Leon Briggs in police custody last November, public calls for police to wear recording body cameras have at last borne some fruit: a pilot scheme on East London has beat officers wearing switchable video cameras for them to record interactions with members of the public. However, some are not as thrilled about the idea of being surveiled while going about their public duty as those members of the public asked and responded who said that public accountability is the only way to restore public trust in the police. Supporters of "Leon's Law" have already expressed concern that these cameras have switches that allow the officers wearing them to turn them on and off at will when the technology exists on a commercial basis to equip officers with continuous-recording HD cameras.

More on this, continually updated with media links."

Link to Original Source
top

Stars In His Eyes: New England Electrician Takes 14kV, Shrugs It Off

ihtoit ihtoit writes  |  about 8 months ago

ihtoit (3393327) writes "An electrician was let with stars in his eyes after an electric shock left him with some unusually shaped cataracts.
The 42-year-old man from New England went to doctors a month after he received a 14,000 V shock to his left shoulder, when his eye sight deteriorated.
He has since had the cataracts removed and although it is believed the cause was damage to his optic nerve doctors are not sure why they were star-shaped.
Sources: New England journal of Medicine, ITV"

Link to Original Source
top

John Doe Lawsuits Baseless, So Says DC Federal Judge

ihtoit ihtoit writes  |  about 8 months ago

ihtoit (3393327) writes "Four people accused of sharing illegal copies of the movie "Elf-Man" persuaded a federal judge there is not enough evidence to support copyright infringement claims against them.
          Elf-Man LLC, producer of the direct-to-DVD release "Elf-Man" sued Eric Cariveau et al. in Federal Court a year ago, accusing them of sharing a peer-to-peer file of the movie.
          Elf-Man claims the defendants illegally copied and distributed the movie online.
          "Despite the industry's efforts to capitalize on internet technology and reduce costs to end viewers through legitimate and legal means of online viewing such as through Netflix, Hulu, and Amazon Prime, there are still those that use this technology to steal motion pictures and undermine the efforts of creators through their illegal copying and distribution of motion pictures," Elf-Man's attorney Maureen VanderMay wrote in the complaint.
          U.S. District Judge Robert Lasnik granted Elf-Man's motion to initiate discovery on the IP addresses of defendants, but noted that "the risk of false positives is very real."
          "It is not clear that plaintiff could ... make factual contentions regarding an Internet subscriber's infringing activities based solely on the fact that he or she pays the Internet bill," Lasnik wrote in the order.
          Elf-Man named 18 individual defendants in its first amended complaint. A default judgment was ordered against two of them; claims against the Doe defendants were dismissed. Claims against four other named defendants were also dismissed on the grounds of their implausibility."

Link to Original Source
top

New views of famed supernova reveal giant dust factory

ihtoit ihtoit writes  |  about 9 months ago

ihtoit (3393327) writes "Astronomers using the ALMA radio telescope in Chile have released images and data showing the oft-postulated but unobserved (until now) dust shell ejected by the supernova remnant SN1987A. "We have found a remarkably large dust mass concentrated in the central part of the ejecta from a relatively young and nearby supernova," astronomer Remy Indebetouw, of the National Radio Astronomy Observatory (NRAO) and the University of Virginia, said in a statement. “This is the first time we've been able to really image where the dust has formed, which is important in understanding the evolution of galaxies." SN1987A was the first catalogued supernova event in our Galactic neighbourhood in 1987. It lies 168,000 light years (987 quadrillion miles) away in the Large Magellanic Cloud, which means that at the time of the explosion, woolly mammoths still roamed Europe and Mitochondrial Eve saw her first sunrise."
Link to Original Source
top

Cancel the eulogy: ISON survives brush with Sun

ihtoit ihtoit writes  |  about 10 months ago

ihtoit (3393327) writes "Comet ISON flew through the sun's atmosphere on Nov. 28th and the encounter did not go well for the icy comet. Just before perihelion (closest approach to the sun) the comet rapidly faded and appeared to disintegrate. This prompted reports of ISON's demise. However, a fraction of the comet has survived. Spaceweather.com has an animation captured from satellites showing the emergence of what remains of our visitor."
Link to Original Source

Journals

ihtoit has no journal entries.

Slashdot Login

Need an Account?

Forgot your password?