AlphaRocketry

With the cost of launching a rocket into space falling, the number of rocket launches is, well, taking off. Last year, governments and companies across the world successfully launched 133 rockets into orbit, breaking a record that stood for 45 years. But there's a catch. Breaking free from Earth's gravity requires a rocket to release a tremendous amount of energy in a short period of time. As a rocket leaves Earth, it produces hot exhaust that changes the physics and chemistry of the atmosphere as it passes through. In a paper published Tuesday in the peer-reviewed journal Physics of Fluids, a pair of physicists simulated the launch of a SpaceX Falcon 9 rocket blasting into space. They found several reasons to be concerned. The carbon footprint isn't the problem  Rockets aren't responsible for putting that much carbon dioxide into the atmosphere. A typical launch burns roughly the same amount of fuel as a day-long commercial flight but produc...

our Instagram page Multiple star systems are very common in the Milky Way. While most of these systems are binary systems consisting of two stars, others contain three, four, or even six stars. These systems tend to be pretty stable since unstable systems tend to break apart or merge fairly quickly, but sometimes you can get a kind of meta-stable system. One that lasts long enough for stars to evolve while still being stable in the end. And that end could be a supernova. It all comes down to gravitational dynamics. In Newtonian physics, two orbiting masses in isolation are always stable. The only paths they can have are elliptical orbits. This is why simple binaries are the most common multiple star systems. Once you have three or more masses, things get more complicated. So complicated that there isn’t an exact solution to the three-body problem, much less four or more. Fortunately, we can make highly accurate orbital models. So while we don’t have an exact solution for multiple star ...

A form of dark energy may cause the accelerating expansion of the universe to come to an end Scientists have developed a new model of the universe which suggests its currently observed accelerated expansion could end as early as 100 million years from now, after which it would transition to a phase of contraction. Researchers, including Paul Steinhardt from Princeton University in New Jersey, say all this may happen “remarkably” quickly, sooner than thought before “Going back in time 65 million years, that’s when the Chicxulub asteroid hit the Earth and eliminated the dinosaurs. On a cosmic scale, 65 million years is remarkably short,” Steinhardt told Live Science. The study, published last month in the journal PNAS, has noted that a form of dark energy (quintessence) could cause the accelerating expansion of the universe to come to an end. Following this change, they say there would be a smooth transition from expansion to a phase of slow contraction. Several studies since...

  The FAA has repeatedly pushed back the estimated release date of the final report. We'll have to wait at least another month to see the results of the U.S Federal Aviation Administration's (FAA) environmental review of SpaceX's Starship program. The FAA has been working for months on that review — officially known as a programmatic environmental assessment (PEA) — which is assessing the environmental impacts of Starbase, the South Texas site where SpaceX has been building and testing its huge Starship vehicle.  The agency published a draft PEA in September and estimated that the final version would be wrapped up by the end of the year. But the FAA has repeatedly delayed the final PEA, generally by a month at a time, citing the need to analyze the public comments submitted in response to the draft report and discuss next steps with other government agencies Late last month, the FAA told us that it expected to release the final PEA today (...