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How to see Venus and a crescent moon side-by-side this Thursday – CNN

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If you live in the Northern Hemisphere and you’ve got a clear sky Thursday, look to the southwest and you’ll see a very bright Venus alongside a crescent moon, together two of the brightest objects in the night sky.

Why Venus is so bright

Venus, also known as the “evening star,” is the third brightest object in the sky after the sun and the moon.
The planet is as bright as it is because of a characteristic called “albedo,” which astronomers use to describe how bright a planet is by specific measurements, according to EarthSky, a website by scientists providing updates on events of the cosmos. When sunlight hits a planet, some of the light is absorbed by the planet’s surface or atmosphere, and some is reflected.
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Albedo is a comparison between the sunlight that strikes an object and how much of it is reflected. The albedo of Venus is close to .7, meaning its thick cloud covering reflects about 70% of the light striking it back into space. Venus is also the Earth’s closest neighbor in the solar system as it’s the planet next-inward from Earth in the orbit around the sun.

Why we’ll see a crescent moon

The moon takes 29.5 days to orbit the Earth. The waxing crescent moon we’ll see Thursday night comes after the new moon we just saw on Sunday, February 23 — meaning the visible side of the moon was between the Earth and the Sun, so we couldn’t see it.
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But as the moon moves away from that position on its journey around the Earth, we’re gradually able to see the side of the moon illuminated by the sun — a waxing crescent moon visible in the western sky for a few days while on its way to becoming full again.

Why they’re meeting and how you can see it

We’re currently in the middle of an “evening apparition” of Venus, which is the period of time during which the planet climbs higher in the sky until it reaches its greatest separation from the sun.
When a planet is at its greatest elongation is when it appears farthest from the sun as seen from Earth, so its appearance is also best at that point. Venus is expected to reach its maximum elongation for the year in the east of the evening sky by March 24, 2020, according to EarthSky. On this night, Venus will stay out for a maximum amount of time after sunset.
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The planets and the moon follow roughly the same path through the sky, which is called the ecliptic. The ecliptic is the plane of the solar system on which all the planets orbit the sun, and the moon travels nearby. The moon and planets occasionally appear to pass closely by each other in the night sky.
In reality, Venus will actually be about 84 million miles from Earth on February 27, while the moon is nearly 250,000 miles away. But our Earthly perspective will still make for a seemingly close sighting.
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As long as the weather is clear, those who live in the Northern hemisphere can see the meeting between the crescent moon and Venus by heading outdoors after sunset and looking to the southwest horizon. Below the constellation Aries, you should see the crescent moon below and to the side of Venus.
If you miss it tonight, you won’t have to wait long before a similar phenomenon occurs in the last days of March.

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Scientists create 'xenobots' that can reproduce – CTV News

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TORONTO —
Scientists in the United States have created robots that can spontaneously self-replicate in what they’re calling a “profound” discovery.

The study, published on Monday in Proceedings of the National Academy of Science,  found that   these computer-designed and hand-assembled organisms called “xenobots” can reproduce in a method not seen in plants and animals.

“People have thought for quite a long time that we’ve worked out all the ways that life can reproduce or replicate, but this is something that’s never been observed before,” Douglas Blackiston, co-author and a senior scientist at Tufts University and Harvard University, said in a news release.

The xenobots were first developed and reported in 2020. They are made from about 3,000 embryonic skin cells of an African clawed frog.

The researchers discovered that these xenobots — when designed properly — can swim around while collecting hundreds of single cells to assemble smaller versions of themselves in their mouths. These smaller xenobots can grow to be full-size within a few days.

This method of reproduction is known as kinematic replication and is common in molecules, but has never been seen in cells or organisms.

“This is profound,” Michael Levin, a co-leader of the study and a professor of biology and director of the Allen Discovery Center at Tufts University. “These cells have the genome of a frog, but, freed from becoming tadpoles, they use their collective intelligence, a plasticity, to do something astounding.”

To discover the xenobots’ reproduction capabilities, the researchers used a supercomputer at the University of Vermont to simulate billions of body shapes to determine what would be ideal for kinematic replication.

Months later, the computer returned a xenobot in a shape that resembled a Pac-Man figure, with a large mouth that can be used to build other xenobots.

“It looks very simple, but it’s not something a human engineer would come up with,” said Sam Kriegman, the lead author of the study and a post-doctoral researcher at Tufts University and Harvard University.

For those concerned about the idea of self-replicating biotechnology, the researchers stress federal, state and institutional ethics experts also approved the study. It is also contained in a lab and can be extinguished easily.

“What presents risk is the next pandemic, accelerating ecosystem damage from pollution, (and) intensifying threats from climate change,” said Joshua Bongard, a computer scientist and robotics expert at the University of Vermont.

“This is an ideal system in which to study self-replicating systems. We have a moral imperative to understand the conditions under which we can control it, direct it, douse it, exaggerate it.”

The researchers also note that this technology has a host of potential benefits for humans, including regenerative medicine, cleaning ocean pollution and vaccine research.

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Citing debris risk, NASA delays spacewalk to fix space station antenna – Financial Post

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A spacewalk planned for Tuesday to repair a faulty antenna on the International Space Station was postponed indefinitely, NASA said, citing a “debris notification” it received for the orbiting research laboratory.

Two U.S. astronauts had been scheduled to venture outside the space station at 7:10 a.m. Eastern time (1210 GMT) to begin their work, facing what NASA officials had called a slightly elevated risk posed by debris from a Russian anti-satellite missile test this month.

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But about five hours before the outing was to have commenced, NASA said on Twitter that the spacewalk had been called off for the time being.

“NASA received a debris notification for the space station. Due to the lack of opportunity to properly assess the risk it could pose to the astronauts, teams have decided to delay the Nov. 30 spacewalk until more information is available,” the space agency tweeted.

It was not made clear how close debris had come to the space station, orbiting about 250 miles (402 km) above the Earth, or whether it was related to the Russian missile test.

NASA TV had planned to provide live coverage of the 6-1/2-hour “extravehicular activity,” or EVA, operation by astronauts Thomas Marshburn and Kayla Brown. The outing would be the fifth spacewalk for Marshburn, 61, a medical doctor and former flight surgeon with two previous trips to orbit, and the first for Barron, 34, a U.S. Navy submarine officer and nuclear engineer on her debut spaceflight for NASA.

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The objective is to remove a faulty S-band radio communications antenna assembly, now more than 20 years old, and replace it with a new spare stowed outside the space station.

According to plans, Marshburn was to have worked with Barron while positioned at the end of a robotic arm operated from inside the station by German astronaut Matthias Maurer of the European Space Agency, with help from NASA crewmate Raja Chari.

The four arrived at the space station Nov. 11 in a SpaceX Crew Dragon capsule launched from the Kennedy Space Center in Cape Canaveral, Florida, joining two Russian cosmonauts and a NASA astronaut already aboard the orbiting outpost.

Four days later, an anti-satellite missile test conducted without warning by Russia generated a debris field in low-Earth orbit, and all seven crew members took shelter in their docked spaceships to allow for a quick getaway until the immediate danger passed, according to NASA.

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The residual debris cloud from the blasted satellite has dispersed since then, according to Dana Weigel, NASA deputy manager of the International Space Station (ISS) program.

But NASA calculates that remaining fragments continued to pose a “slightly elevated” background risk to the space station as a whole, and a 7% higher risk of spacewalkers’ suits being punctured, as compared to before Russia’s missile test, Weigel told reporters on Monday.

Although NASA has yet to fully quantify additional hazards posed by more than 1,700 larger fragments it is tracking around the station’s orbit, the 7% higher risk to spacewalkers falls “well within” fluctuations previously seen in “the natural environment,” Weigel said.

Still, mission managers canceled several smaller maintenance tasks under consideration for Tuesday’s spacewalk, Weigel added. (By Steve Gorman. Editing by Gerry Doyle)

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A new approach to flagship space telescopes – The Space Review

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The astrophysics decadal survey recommended a scaled-down version of a space telescope concept called LUVOIR as the first in a line of flagship space observatories to be developed over the next few decades. (credit: NASA/GSFC)

For much of this year, the biggest puzzle for astrophysicists had nothing to do with dark matter, dark energy, or discrepancies in the value of the Hubble Constant. Instead, the question at the top of their minds was: when was Astro2020 coming out?

Astro2020 was the shorthand for the latest astrophysics decadal survey, the once-a-decade review of the state of the field and recommendations for both ground- and space-based projects to pursue to answer the top scientific questions. The final report by the decadal survey’s steering committee, once expected in late 2020 as the name suggests, had slipped to some time in 2021 because of the pandemic, which forced a shift from in-person to virtual meetings just as work on the survey was going into high gear.

The decision to pick a concept between LUVOIR and HabEx was driven by science and budgets: big enough to do meet key science objectives like characterizing exoplanets, but also small enough to fit into a reasonable cost and schedule.

The committee itself kept quiet about its work, providing little specific guidance about when to expect the final report. At a meeting of NASA’s Astrophysics Advisory Committee in October, Paul Hertz, director of the agency’s astrophysics division, presented the results of an office pool from earlier in the year predicting when the report would be released. All but two thought the report would have already been released by the mid-October meeting of that committee; those two predicted it would be released the week of Thanksgiving.

Fortunately, they and the rest of the astrophysics community did not have to wait until last week’s holiday to get their hands on the report. The document, released November 4, provided astronomers with a long-awaited roadmap for not just the next decade but arguably through the middle of the century, endorsing a set of observatories that can peer back into the distant early universe and also look for habitable worlds close to home.

While the decadal survey makes a series of recommendations for smaller missions and ground-based telescopes, what gets the most attention is its recommendation for a large strategic, or flagship, space mission. That recommendation is just that—NASA isn’t bound to accept it—yet the agency has adopted the top-ranked flagship missions of previous decadals. That includes the one picked in the previous decadal in 2010, which became the Wide-Field Infrared Survey Telescope (WFIRST), renamed by NASA to the Nancy Grace Roman Space Telescope last year.

NASA, in preparation for Astro2020, commissioned detailed studies of four proposed flagship observatories, operating from far infrared to X-ray wavelengths (see “Selecting the next great space observatory”, The Space Review, January 21, 2019.) These studies offered detailed technical, scientific, and budgetary information for the concepts, which were effectively finalists for the being the next flagship mission—although the decadal survey was not under any obligation to pick one.

And, in the end, they didn’t pick one of the four. Instead, the recommended flagship mission was something of a compromise between two of the concepts. One, the Habitable Exoplanet Observatory, or HabEx, proposed a space telescope between 3.2 and 4 meters across optimized to search for potentially habitable exoplanets. The other, the Large Ultraviolet Optical Infrared Surveyor, or LUVOIR, proposed a large space telescope between 8 and 15 meters across for use in a wide range of astrophysics, from exoplanet studies to cosmology.

What the decadal recommended was a telescope six meters across capable of observations in ultraviolet, visible, and infrared wavelengths: similar to LUVOIR but scaled down to a size between the smaller version of LUVOIR and HabEx.

The decision to pick a concept between LUVOIR and HabEx was driven by science and budgets: big enough to do meet key science objectives like characterizing exoplanets, but also small enough to fit into a reasonable cost and schedule. “We thought that six meters provides assurance of enough target planets, but it’s also a big enough gain in capability over Hubble to really enable general astrophysics,” said Robert Kennicutt, an astronomer at the University of Arizona and Texas A&M University who was one of the two co-chairs of the decadal survey committee.

“We realized that all of these are visionary ideas but they require timelines that are pan-decadal, even multi-generational,” said Harrison. “We really think a different approach needs to be taken.”

That telescope—not given a name by the decadal survey—will still be expensive and take a long time to build. The decadal’s estimates, which included independent cost and schedule analyses, projected the telescope would cost $11 billion to build, in line with the James Webb Space Telescope when accounting for inflation, and be ready for launch in the first half of the 2040s. But the original LUVOIR concept would have cost $17 billion and not be ready until the 2050s, according to those same analyses. HabEx, the decadal survey concluded, would have been cheaper but too small to meet many of those science goals.

That selection of a flagship mission was, alone, not that different than past decadal surveys. Even that compromise pick is not unprecedented, as the previous decadal’s recommendation of what would become Roman emerged from combining several concepts. What was different, though, was the realization that, after the delays and cost overruns suffered by past flagships, notably the James Webb Space Telescope, NASA needed a different approach to developing such missions.

“We realized that all of these are visionary ideas but they require timelines that are pan-decadal, even multi-generational,” said Fiona Harrison of Caltech, the other co-chair of the steering committee, referring to the four flagship concepts studied for the decadal. “We really think a different approach needs to be taken.”

What the decadal survey recommended was that the space telescope it recommended be just the first mission to emerge from a new Great Observatories Mission and Technology Maturation Program at NASA. That program would mature technologies for a series of flagship missions in a coherent fashion.

“The survey committee expects that this process will result in decreased cost and risk and enable more frequent launches of flagship missions, even if it does require significantly more upfront investment prior to a decadal recommendation regarding implementation,” the committee concluded in the report.

Specifically, it recommended that, five years after starting work on the large space telescope that was the report’s top priority, NASA begin studies of two other flagship missions, a far infrared space telescope and an X-ray observatory, at estimated costs of $3–5 billion each. Both are similar to the other two flagship mission concepts studied by NASA for this decadal survey, the Origins Space Telescope and Lynx X-ray Observatory.

Setting up studies of those future mission concepts, without committing to them, allows NASA to adapt if both technologies or science goals change, another member of the decadal survey steering committee noted. “If the progress appears to be stalled or delayed, then we can rapidly onramp another one of the compelling, exciting ideas,” said Keivan Stassun of Vanderbilt University. “We can be phasing in multiple great ideas.”

“We were tasked and encouraged by the funding agencies, including NASA, to really think big, bold, ambitious, and long-term,” Stassun said.

The idea that it takes a long time to develop flagship space telescopes is not new: the first studies of JWST, originally called the Next Generation Space Telescope, predate the launch of the Hubble Space Telescope more than three decades ago, and that spacecraft is only now about to launch. But the study’s proposal recognizes that the problems experienced by JWST and, to a lesser extent, Roman, require a different approach to managing such complex, expensive missions.

It also reflects the realization that some of the questions that astrophysics is seeking to answer can’t be easily fit into decade-long timeframes. “We were tasked and encouraged by the funding agencies, including NASA, to really think big, bold, ambitious, and long-term,” Stassun said. “We took that to mean that we should not be thinking only about that which can be accomplished in a ten-year period.”

NASA’s Hertz had, in fact, urged the decadal survey to be bold on many occasions before and during its deliberations. “I asked the decadal survey to be ambitious, and I believe they are certainly ambitious,” he said at a November 8 meeting of the Committee on Astronomy and Astrophysics of the National Academies’ Space Studies Board.

NASA is only starting to review the overall recommendations of the decadal, he said. That includes not just its analysis of flagship missions but endorsement of a new medium-class line of “probe” missions, with a cost of $1.5 billion per mission and flying once a decade. Such missions would be analogous to the New Frontiers line of planetary science missions that fall between planetary science flagships and smaller Discovery class missions.

The delay in completing the decadal means it won’t have an impact on NASA’s next budget proposal for fiscal year 2023, which is already in active development for release in early 2022. Hertz said he’ll provide some initial comment on the decadal at a town hall meeting during the American Astronomical Society meeting in early January, particularly any recommendations that can be accommodated in the fiscal year 2022 budget. A complete, formal response will come later next year after a series of town hall meetings.

Those plans will depend on budgets. The first views Congress has on the decadal, including its flagship mission plans, will come Wednesday when the House Science Committee’s space subcommittee holds a hearing on the report.

Hertz was optimistic in general about the state of NASA’s astrophysics programs, citing the impending launch of JWST and Roman passing its critical design review. “I’m really excited. This is a great time for astrophysics,” he said. Astronomers hope the decadal’s recommendations, if implemented, can make it a great few decades for the field.


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