Ivan Tuzikov

I think my post was rather inexplicit in terms of wording. Say, I set through Radeon Settings a 30 fps limit and V-sync OFF and my display cap is 60 Hz. Will the display show each rendered frame twice to correspond to 60 Hz display? Will it eliminate tearing?

I have a 7870 Radeon GPU in my PC. Display is set to 60 Hz (maximum supported). Could somebody please explain me the following things: 1. When I turn Vsync ON, set FPS limit to 60 and the GPU renders less than 60 FPS, for example 43, which would be the actual number of displayed frames? 2. When I turn Vsync OFF, set FPS limit to 30 and the GPU renders more than 30 FPS, for example 33, which would be the actual number of displayed frames? Thanks for advance!

I didn't quite get: which anomaly can reveal inhabited submerged base in the Solar system? You suppose that there are instruments that can detect operating hidden nuclear reactor in the Solar system? Wouldn't neutrinos from other stars, Terran reactors and the Sun mask the flux of neutrinos from ET's reactor? Besides, ET's can obtain thermal energy from the core of a celestial body using thermal wells.

You 've got it! I actually meant evidences, not absolute 101% disproval. I know, the Science can't prove absence with 100% certainty. But what would be probable evident signs of such hypothetical colony that can be measured with current science instruments?

How would Modern Science disprove the possibility of autonomous ET's colony hidden under surface inside some celestial body of the Solar System? Can such hypothetical undersurface base sustain a colony with population of say, 5 thousand beings (as a model one can use humans because of known biology) for, say 2000 years and remain undetected until now? I've Googled some info about technosignatures, biosignatures and waste heat production but I' don't have enough data and enough knowledge in biology, physics and industrial processes as to reject such hypothesis or accept it. Thanks in advance to everybody for your attention and time!

Well, when the speed is high it is more hard to maneuver, isn't it? As well as to detect any obstacles in advance.

Let's take as an example a Deuterium-Deuterium fusion spacecraft. The estimated exhaust velocity is fairly high, an estimated 19,000 km/s (0.063 c) which means a 120,000 ton starship attached to 12,000,000 tons of deuterium can do a delta-vee of ~0.29 c. With an efficient magnetic sail that means the journey speed approaches ~0.29 c, albeit with the mass-penalty of the sail. Is it really possible to flight at speed of 0.063*c or faster through Kuiper belt, Hill's cloud and Oort cloud to, say Proxima Centauri and not collide with something. There is an opinion that we are going to collide in case of fast interstellar travel - http://boards.straightdope.com/sdmb/showthread.php?t=689927 And there is also an opinion that fusion spacecrafts are unfeasible. http://www.wired.com/2008/08/space-limits/ http://physics.ucsd.edu/do-the-math/2012/01/nuclear-fusion/ So, how probable is collision during relatively fast interstellar travel (0.063*c or faster)?

I don't quite understand the specific impulse notion. If one uses 10 engines with the same thrust would it be 700 km/s x 10 = 7000 km/s?

Again, and what about durability of materials that constitute complex electronic and electro-mechanical systems?

I also reference to diffusion processes in electronic chips and other complex equipment. Well, I've picked up the most speedy design from wiki. As for "speed records" https://en.wikipedia.org/wiki/List_of_vehicle_speed_records#Spacecraftthe fastest is 252,792 km/h relative to the Sun or 70 km/s, ten times slower than the proposed rocket.

Unmanned Expedition to the https://en.wikipedia.org/wiki/Wolf_1061c Let’s consider that mankind is able to build a version of: https://en.wikipedia.org/wiki/Fusion_rocket Namely: The NASA/MSFC Human Outer Planets Exploration (HOPE) group has investigated a manned MTF propulsion spacecraft capable of delivering a 163933-kilogram payload to Jupiter's moon Callisto using 106-165 metric tons of propellant (hydrogen plus either D-T or D-He3 fusion fuel) in 249–330 days.[5] This design would thus be considerably smaller and more fuel efficient due to its higher exhaust velocity (700 km/s). In 2006, the United States was estimated to have a production capacity of 11 million tons of hydrogen. https://en.wikipedia.org/wiki/Hydrogen_production To travel to the Wolf 1061c, 700 km/s design (the rocket) would take 428 years to travel 1 light year (l.y.) and 5906.4 years to travel full distance of 13.8 l.y. and deliver 164 tons payload. In Wikipedia example 165 tons of properllant are needed for 330 days travel, so 182 tons per year, which means that about 1075000 tons of fuel for 5906 years one-way trip. Let us assume that the rocket holds 2 robotic spacecrafts (orbiter for planet exploration and space radio communicator) and a robot-operator. The orbiter studies the planet for some time (for example, 10 years) and constantly sends the data to the communicator that orbits the Wolf 1061 star and uses it as gravitational lens to relay data back to the Solar system. The robot-operator controls the whole process. When we take into account such hypothetical plan I wonder about materials, equipment, devices, electronics – diffusion of materials. Will these 2 spacecrafts survive the journey in off-state and under maintenance of the robot-operator. And for how long the robot-operator and the electronics and mechanicsms of the rocket are expected to last? In short: can the above-listed equipment still be operable after 5906 years of space travel?

OK, thanks to everybody for answers, I got it.

No, I am not. I primarily meant human.

Well, maybe my next two questions is slightly off-top, but could somebody plesase answer me: 1) is it possible to parachute jump a human (or other living being) from aerobraking rocket in order not to land the rocket and hide the fact of flyby? 2) is it possible to detect distinctive traces of rocket fuel of flyby rocket in earth/water and the traces left in space?

And in case of chemical rocket?

Yeah, probably if a descent vehicle have to land and than take off, well, should this happened in the 20th century people would have discovered the sites of landing and launch, imho.

Well, was it possible for astonomers in developed countries in 1900 /1920 / 1940 (before the space era) to detect decceleration plume and atmospheric entry of a landing module holding 1 human (for example) that lands not farther than several hundred km from the populated areas?

OK, let's imagine for this mental experiment, that the size is similar to that of Apollo lander and the distance is: Earth surface - Earth Thermosphere.

Great thanks to everybody who participated in the discussion, but it seems that we digressed from the subject. Again, can somebody, who knows the history of astronomy answer me, at least approximately: at which point of astronomic observations (the year, or decade) was there enough number of Earth astronomers and telescopes to detect the incoming spacecraft by its exhaust plume during acceleration or deceleration?

Well, for example, a spacecraft, which can carry 1 living being (human, for instance) that starts from far side of the Moon, enters Earth atmosphere, lands, than launches and returns to the point of departure. Another hypothetic examples are: everything the same, except that the start takes place from the Pluto or Halley's comet when it is close to the Earth. I gave these description instead of calculations of size, temperature and brightness which I do not know how to perform correctly. P.S. I've watched the series Ancient Aliens several years ago and it sank into my mind. I've studied Wiki, some science sites and realized that the whole series is a mere pseudo-science. And now I try to find is there any scientific basis for speculations on alien visitations taking into account real physics (that is no FTL travel, wormholes, etc.)

You are getting close to my initial questions, actually 2 main questions: The first one: possibility of detection of plume in case of interplanetary travel in the Solar system (Earth-bound). The second one: at which point of astronomic observations (the year, or decade) was it possible for Terran astronomers to detect the incoming spacecraft (interstellar or interplanetary) by its exhaust plume? P.S. Please, do not answer in riddles or parry my questions, I'm neither astronomer nor scientist (sadly). Any useful links would be of much help. Thanks in advance.

Telescopes? What about breaking, at the end of their journey?

1. How else can we detect (alien / in radiosilence mode) spacecrafts in deep space? 2. Of course, but to gain the required speed the spacecraft has to fire its engines for some period of time.

https://en.wikipedia.org/wiki/Timeline_of_telescopes,_observatories,_and_observing_technology http://www.projectrho.com/public_html/rocket/spacewardetect.php The second link specifies calculations for the following: chemical rockets; fusion engines, ion drives, steady-state plasma drives - most types of torchships. Taking into account the aforementioned links could somebody please answer me at which point of astronomic observations (the year, or decade) was it possible for Terran astronomers to detect the incoming spacecraft (interstellar or interplanetary) by its exhaust plume?

I've found some answers. No more replies are required.