Missouri will fire 'sound cannons' at drivers to deter work zone speeding
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By noobient · Posted
Python programmers in a nutshell. Now, guess what lang most AI programmers use... :-) -
By Jaybonaut · Posted
There was nothing whatsoever wrong with Vista as an OS after the SP1 update. People who claim it wasn't were using ancient machines for some silly reason. Not kidding, no hyperbole/exaggeration. Vista was good. -
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By Michal H. · Posted
Dude, im talking about simply disable it from settings app. Because of the eu regulation, you could disable it here for years. -
By hellowalkman · Posted
One big question about Mars was answered thanks to Einstein's 100 year old theory by Sayan Sen Image via DepositPhotos Scientists at the U.S. National Institute of Standards and Technology (NIST) have calculated how time passes on Mars compared with Earth, adding detail to how timekeeping would need to work beyond Earth’s orbit. The study, published in The Astronomical Journal, found that clocks on Mars run an average of 477 microseconds, or millionths of a second, faster per day than clocks on Earth. A microsecond is one millionth of a second, a very small unit used in precise scientific timing systems such as atomic clocks, which measure time using consistent atomic behavior. This difference is not constant. Because Mars moves around the Sun in a non-circular path (an eccentric orbit, meaning its distance from the Sun changes over time instead of staying fixed) and is affected by gravity from other bodies, the daily difference can vary by as much as 226 microseconds over a Martian year. The study also identifies smaller repeating changes of about 40 microseconds per day linked to synodic cycles (repeating periods that describe how planets line up with each other as they orbit the Sun from different positions). These longer patterns affect how time differences slowly rise and fall. To make these estimates, researchers compared Mars with Earth and the Moon. The work looks at relativistic proper time (the time actually measured by a clock depending on its speed and the strength of gravity where it is located, as described in Einstein’s relativity). This shows that each world has its own slightly different “rate” of time. This becomes more important as space missions expand into cislunar space (the region between Earth and the Moon) and toward Mars. On Earth, time systems rely on atomic clocks and satellites, which stay closely synchronized for navigation and communication. The study is based on Albert Einstein’s theory of relativity, which shows that time is affected by gravity and motion. Stronger gravity makes clocks run slower, while weaker gravity makes them run faster. “The time is just right for the Moon and Mars,” said NIST physicist Bijunath Patla. “This is the closest we have been to realizing the science fiction vision of expanding across the solar system.” A day on Mars is about 40 minutes longer than on Earth, and a Martian year lasts 687 Earth days. But the main question is not just about days and years, but how fast time itself passes. An atomic clock placed on Mars would function normally, but compared with one on Earth, the two would slowly drift apart due to differences in gravity and motion. This requires careful calculation of what is similar to a time-zone difference across planets. Researchers modeled Mars using a reference surface and included gravitational effects from the Sun, Earth, the Moon, and other planets. This includes a multi-body gravitational system (often described as a three-body or four-body problem, where predicting motion becomes difficult because multiple large objects all pull on each other at the same time through gravity). Mars also follows a Keplerian orbit (an idealized elliptical orbit based on simple gravitational laws that assume smooth motion, before adding real-world disturbances from other bodies). In addition, the researchers accounted for solar tides (small changes in gravitational force caused by the Sun that slightly distort planetary motion and timing, especially in systems involving Earth and the Moon). These combined effects are described as relativistic proper-time offsets (small but measurable differences in elapsed time between locations caused by gravity and motion), which must be included when comparing clocks across planets. “But for Mars, that’s not the case. Its distance from the Sun and its eccentric orbit make the variations in time larger. A three-body problem is extremely complicated. Now we’re dealing with four: the Sun, Earth, the Moon and Mars,” Patla explained. “The heavy lifting was more challenging than I initially thought.” Although the differences are extremely small, they matter for navigation and communication systems that depend on precise timing. Even modern networks on Earth, such as mobile systems, rely on timing accuracy at very small fractions of a second. Communication between Earth and Mars currently takes about four to 24 minutes or more depending on planetary positions, meaning signals are not real-time. A shared and accurate time system could help future missions reduce confusion in navigation and data exchange. “If you get synchronization, it will be almost like real-time communication without any loss of information. You don’t have to wait to see what happens,” Patla said. Researchers note that fully developed interplanetary communication networks are still far in the future. However, understanding how time behaves across planets helps prepare for those systems. “It may be decades before the surface of Mars is covered by the tracks of wandering rovers, but it is useful now to study the issues involved in establishing navigation systems on other planets and moons,” said Neil Ashby. “Like current global navigation systems like GPS, these systems will depend on accurate clocks, and the effects on clock rates can be analyzed with the help of Einstein’s general theory of relativity.” Patla added that the results also help improve understanding of time itself under relativity. “It's good to know for the first time what is happening on Mars timewise. Nobody knew that before. It improves our knowledge of the theory itself, the theory of how clocks tick and relativity,” he said. Source: NIST, IOPscience This article was generated with some help from AI and reviewed by an editor. Under Section 107 of the Copyright Act 1976, this material is used for the purpose of news reporting. Fair use is a use permitted by copyright statute that might otherwise be infringing.
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