Hexbyte Glen Cove Five things to know about the James Webb Space Telescope

Hexbyte Glen Cove

Webb’s centerpiece is its giant primary mirror, a concave structure 21.5 feet (6.5 meters) wide and made up of 18 smaller hexagonal mirrors.

The James Webb Space Telescope, the most powerful space observatory ever built, is finally set for launch in late December after decades of waiting.

An engineering marvel, it will help answer fundamental questions about the Universe, peering back in 13 billion years. Here are five things to know.

Giant gold mirror

The telescope’s centerpiece is its enormous primary mirror, a concave structure 21.5 feet (6.5 meters) wide and made up of 18 smaller hexagonal mirrors. They’re made from beryllium coated with gold, optimized for reflecting from the far reaches of the universe.

The observatory also has four , which together fulfill two main purposes: imaging , and spectroscopy—breaking down light into separate wavelengths to study the physical and chemical properties of cosmic matter.

The mirror and instruments are protected by a five-layer sunshield, which is shaped like a kite and built to unfurl to the size of a tennis court.

Its membranes are composed of kapton, a material known for its high heat resistance and stability under a wide temperature range—both vital, since the Sun-facing side of the shield will get as hot as 230 degrees Fahrenheit (110 degrees Celsius), while the other side will reach lows of -394F.

The telescope also has a “spacecraft bus” containing its subsystems for electrical power, propulsion, communications, orientation, heating and data handling; all told, Webb weighs around as much as a school bus.

Graphic of the James Webb space telescope, the successor to Hubble, and where it will be stationed after launch on December 22.

Million-mile journey

The telescope will be placed in orbit about a million miles from Earth, roughly four times the distance of our planet from the Moon.

Unlike Hubble, the current premier space telescope that revolves around the planet, Webb will orbit the Sun.

It will remain directly behind Earth, from the point of view of the Sun, allowing it to remain on our planet’s night side. Webb’s sunshield will always be between the mirror and our star.

It will take about a month to reach this region in space, known as the second Lagrange point, or L2. While astronauts have been sent to repair Hubble, no humans have ever traveled as far as Webb’s planned orbit.

High-tech origami

Because the telescope is too large to fit into a rocket’s nose cone in its operational configuration, it has to be transported folded, origami style. Unfurling is a complex and challenging task, the most daunting deployment NASA has ever attempted.

About 30 minutes after take-off, the communications antenna and supplying it with energy will be deployed.

Because the telescope is too large to fit into a rocket’s nose cone in its operation form, it has to be transported folded, origami style.

Then comes the unfurling of the sunshield, hitherto folded like an accordion, beginning on the sixth day, well after having passed the Moon. Its thin membranes will be guided by a complex mechanism involving 400 pulleys and 1,312 feet of cable.

During the second week will finally come the mirror’s turn to open. Once in its final configuration, the instruments will need to cool and be calibrated, and the mirrors very precisely adjusted.

After six months the telescope will be ready to go.

Life, the universe, and everything

Webb has two primary scientific missions, which together will account for more than 50 percent of its observation time. First, explore the early phases of cosmic history, looking back in time to only a few hundred million years after the Big Bang.

Astrologers want to see how the very first stars and galaxies formed, and how they evolve over time.

Its second major goal is the discovery of exoplanets, meaning planets outside the solar system. It will also investigate the potential for life on those worlds by studying their atmospheres.

The great promise of Webb lies in its infrared capacity.

Comparison of the space telescopes Hubble, in orbit since 1990, and its successor the James Webb telescope, to be launched on December 22.

Unlike the ultraviolet and visible light Hubble mostly operates in, the longer wavelengths of infrared penetrate dust more easily, allowing the early universe shrouded in clouds to come more clearly into view.

Infrared also lets scientists go further back in time because of a phenomenon called redshifting. Light from objects farther away is stretched as the universe expands, towards the infrared end of the spectrum.

Also planned are closer observations, in our solar system, of Mars and of Europa, Jupiter’s icy moon.

Decades in the making

Astronomers began debating the that should succeed Hubble in the 1990s, with Webb’s construction beginning in 2004.

Launch has been pushed back several times, initially penciled for 2007, then 2018…mainly because of the complexities associated with development.

The observatory is the result of an immense international collaboration, and integrates Canadian and European instruments.

More than 10,000 people worked on the project, with the budget eventually snowballing to around $10 billion.

The mission is set to last for at least five years, but hopefully 10 or more.

© 2021 AFP

Five things to know about the James Webb Space Telescope (2021, December 10)
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Hexbyte Glen Cove 5 things Joe Biden can do to fight climate change—without Congress' help thumbnail

Hexbyte Glen Cove 5 things Joe Biden can do to fight climate change—without Congress’ help

Hexbyte Glen Cove

by Anna M. Phillips, Los Angeles Times

Credit: CC0 Public Domain

Climate change is fueling record-breaking fires, hurricanes and floods. Global emissions of greenhouse gases are returning to pre-pandemic levels. And America—which has emitted more planet-warming gases than any other nation—has just become the only country to quit the Paris climate agreement.

President-elect Joe Biden is a few months away from inheriting a seemingly impossible situation: a country where the majority of people say they are in favor of action but where a divided government in Washington will complicate any efforts to do so.

If Republicans keep control of the Senate, then much of the legislation that would be needed to implement Biden’s aggressive plans to tackle climate change would likely be blocked.

But there is a huge amount that Biden can accomplish on his own. Here’s a look at five areas of environmental policy that the next president can change without so much as a phone call to Senate Majority Leader Mitch McConnell.

Make America drive like California, again

One of the most significant steps Biden could take to reduce greenhouse gas emissions would to be reinstate tough nationwide rules for auto emissions and mileage standards that were put in place under the Obama administration and that essentially mirrored regulations already in effect in California.

These rules are important because transportation is a top source of planet-warming gases. When they were put in place, they were considered one of the nation’s most successful efforts to combat climate change.

But the Trump administration weakened those rules. Under the Trump regulations, nearly 900 million more tons of carbon dioxide are expected to be released than under the Obama-era standards, a result of less efficient cars burning an additional 78 billion gallons of fuel. The administration also revoked California’s authority to set stricter auto emissions rules than those required by the .

The battle over car emissions was headed for the Supreme Court, where the conservative majority might have decided in favor of the Trump administration.

But Biden has promised to reinstate the Obama standards and make them tougher, expanding them beyond passenger vehicles and SUVs into the most polluting trucks. He’s also likely to grant California a new waiver, allowing it and the 13 other states that have adopted its standards to crack down even more on tailpipe pollution.

End new oil drilling on federal land

The president and whomever he chooses to serve as his Interior secretary will have broad authority to decide what kind of energy development should take place on land owned by the federal government. On this question, Biden has been clear—he has said he would not issue new leases for fracking on federal lands.

Biden could issue a new executive order directing the Interior Secretary to halt all oil and gas lease sales and permits. This would not block oil production that’s already taking place, but it would prevent more wells from being drilled and would allow for a gradual transition away from natural gas. The Obama administration used the same strategy to prevent the sale of new coal mining rights.

A Biden Interior Department could also impose new requirements on oil companies operating on federal land, such as a rule mandating the capture of methane from wells and other infrastructure. Methane emissions are a major contributor to global warming and have been rising sharply.

It may also be possible for Biden to unravel some of the leasing that’s been carried out under the Trump administration, which has auctioned off millions of acres of federal land. Federal judges have already intervened in some instances to suspend or void hundreds of leases because of procedural mistakes and legal violations by the Interior Department.

Experts said that a Biden administration could go further by voiding leases that have been issued, but where the land hasn’t been developed, or by buying them back.

This could affect the Trump administration plans to auction off more than 4,000 acres of federal land and mineral estate in California this December—the first lease sale in the state since 2012.

Develop the Clean Power Plan 2.0

Established under the Obama administration, the Clean Power Plan regulated from power plants, the nation’s second-largest source of planet-warming gas. But in 2019, Trump’s Environmental Protection Agency replaced this plan with a new rule designed to protect the coal industry while backing away from any meaningful emissions reductions.

Whereas the Clean Power Plan was expected to reduce emissions by about 30% by 2030, EPA projections suggest the replacement rule might reduce carbon dioxide emissions by 0.7%, or possibly not at all.

Under a Biden administration, the EPA could repeal the Trump rule without any input from the Senate. But when it comes to replacing it, many environmental advocates are hopeful that the president will decide to go further than simply re-proposing the Clean Power Plan. That’s because the Obama-era plan has been tied up in the courts and there is doubt it could survive a review by a Supreme Court that now has a conservative 6-to-3 majority.

Instead, advocates hope that Biden’s EPA will propose a more ambitious rule, one that would put the country on a path to meeting the president-elect’s goal of eliminating carbon emissions from the electricity sector by 2035.

Promote climate policy through foreign policy

Biden has already said he will rejoin the Paris climate agreement, but there’s much more he could do to show the world that the United States is serious about fighting climate change.

A report from Brown University’s Climate Solutions Lab lays out a series of steps that include creating a “climate club” of countries that volunteer to reduce emissions by agreeing to set a minimum price on carbon and penalize high-emitting countries through trade measures such as tariffs.

Another proposal outlined in the report calls for Biden to work with the European Union—the largest importer of natural gas—as well as Canada and Mexico to curb methane emissions.

Declare climate change a national emergency

Some environmental advocates have said that because we are barreling toward catastrophe, Biden should invoke emergency authority to address climate change. This step would be bold—quite possibly bolder than Biden is willing to be—and it would carry major rewards and risks.

Under emergency authority, a Biden administration could use military funding to quickly move the country away from coal and gas-powered plants and toward renewable energy. He could also increase the number of electric-vehicle charging stations, require automakers to produce more electric vehicles, and accelerate the expansion of clean-energy technology—all without having to ask Congress to approve new funding.

If this sounds familiar, it might be because Trump declared a national emergency on the border in 2019 in order to access billions of dollars in funding for a border wall, which lawmakers had refused to give him. Questions over the legality of the declaration have been fought over in the cou

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