Posted on by Bob King

Tiangong 1 Falls, Blue Moon Rises and Mars Takes Aim At Saturn

Bob King
A couple watches the Moon rise from the icy shore of Lake Superior in Duluth earlier this month on March 1. Credit: Bob King

I apologize for the end-of-the-world title, but everything in it is true. And the world will still be here after it’s all done. On Friday (March 31) at 7:36 a.m. Central Time, the Moon will be full for the second time this month, which makes it a Blue Moon according to popular usage. Enjoy it. What with January’s Blue Moon and now this, we’ve chewed through all our Blue Moons till Halloween 2020.

I look forward to every full moon. Watching a moonrise, we get to see all manner of amazing atmospheric distortions play across the squat, orange disk. Once the sky’s dark, its outpouring of light makes walking at night a pleasure.

When a full moon occurs in spring, it hurries south down the ecliptic, the imaginary circle in the sky defining Earth’s orbit around the Sun. For northern hemisphere skywatchers, this southward sprint delays its rising by more an hour each night, forcing a quick departure from the evening sky. And that means blessed darkness for hunting down favorite galaxies and star clusters.


Tiangong 1 and a reentry simulation

As the Moon rolls along, the hapless Chinese space station Tiangong 1 hurtles toward Earth. Drag caused by friction with the upper atmosphere continues to shrink the spacecraft’s orbit, bringing it closer and closer to inevitable breakup and incineration. Since the Chinese National Space Administration (CNSA) lost touch with Tiangong 1 in March 2016, mission control can no longer power thrusters to de-orbit it at chosen time over a safe location like the ocean. The 9.3-ton (8,500 kg) station will burn up somewhere anywhere over a vast swath of the planet between latitudes 43°N and 43°S. Included within this zone are the southern half of Europe, the southern two-thirds of the U.S., India, Australia and much of Africa and South America.

Not until the day of or even hours before will have a clear idea of when and where the station will meet its fate. According to the latest update from the Aerospace Corp., which monitors falling spacecraft, reentry is expected on Easter Sunday (April 1) at 10:30 UT / 5:30 a.m. Central Time plus or minus 16 hours. This morning (March 29), the space station is circling Earth at about 118 miles (190 km) altitude. The lowest a satelllite can still make a complete orbit of the planet is about 62 miles (100 km). Below that, break-up begins.

A high definition TV camera on an aircraft took this photo of the cargo ship ATV-1 reentering the atmosphere in September 2008. Tiangong 1 is about the same size and will likely shatter and burn in similar fashion. Credit: ESA/NASA

For up-to-the-minute updates on when to expect Tiangong 1’s orbit to decay and the machine to plunge to Earth, check out Joseph Remis’ Twitter page. Most of the space station is expected to burn up on reentry, but larger chunks might survive all the way to the ground. Since much more of the Earth’s surface is water these remnants will likely end up in the drink … but you never know. If Tiangong-1 does come down over a populated area, observers on the ground will witness a spectacular, manmade fireball day or night.

Mars (right) and Saturn pair up in Sagittarius this morning, March 29 at dawn seen from Duluth, Minn. The two planets were 2.2° apart. Details: 35mm lens, f/2.8, 13 second exposure at ISO 800. Credit: Bob King

On the quieter side but nearly as eye-catching, Mars will overtake Saturn in the coming week, passing just 1° south of the ringed planet in a thrilling dawn conjunction on April 2. If the weather forecast doesn’t look promising that morning, the two planets will remain within 2° of each other now through April 6th, providing plenty of opportunities for a look.

You can easily tell them apart by color: Mars is distinctly red-orange and Saturn looks creamy white. Both are bright at around magnitude 0 though Mars is now a hair brighter by two-tenths of a magnitude. Will you be able to see the difference?

Mars passes close to Saturn on Monday, April 2. Look low in the southeastern sky shortly before and at dawn. Try getting a picture of the lovely couple by setting up your camera on a tripod and doing a series of time exposures from 5-30 seconds at f/3.5 and ISO 800. No fancy telephoto equipment is needed: a 35-55mm lens is perfect. Created with Stellarium

In most telescopes at low magnification both planets will comfortably fit in the same field of view. Saturn’s rings are tilted nearly wide open and quite beautiful. Mars appears gibbous and though still rather small, it’s brightening rapidly and drawing closer in time for its closest approach to Earth since 2003. Wishing you clear skies!

Posted on by Fraser Cain

Weekly Space Hangout: March 28, 2018: Austin Wintory & Anthony Lund – “A Light In The Void”

Hosts:
Fraser Cain (universetoday.com / @fcain)
Dr. Paul M. Sutter (pmsutter.com / @PaulMattSutter)
Dr. Kimberly Cartier (KimberlyCartier.org / @AstroKimCartier )
Dr. Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg & ChartYourWorld.org)

Special Guests:
This week, we are excited to welcome Austin Wintory and Anthony Lund to discuss their new collaborative Kickstarter campaign, “A Light in the Void,” a live concert experience that will tell the story of science through live music, scientists’ live presentations, video, animations, and more.

Austin Wintory is a Grammy-nominated and two-time BAFTA-winning composer who has scored almost 50 feature films in addition to composing and appearing in concerts worldwide, as well as creating the scores for a long list of videogames, including Ubisoft’s Assassin’s Creed Syndicate for which he wrote and produced the score.

Anthony Lund is a three-time Emmy nominated writer, producer, and director who focuses his work on both science fiction and science fact. He is known for his work on Through the Wormhole as well as NatGeo’s Breakthrough.

You can find out more about Austin by visiting his website: https://www.austinwintory.com

You can find out more about Anthony by visiting his LinkedIn profile: https://www.linkedin.com/in/tony-lund-8247057/

Want to support the “A Light in the Void” Kickstarter? You can do so by visiting the webpage for the campaign: https://www.kickstarter.com/projects/litvconcert/a-light-in-the-void-live-concert-and-broadcast-eve?wsh

Announcements:
If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

We record the Weekly Space Hangout every Wednesday at 5:00 pm Pacific / 8:00 pm Eastern. You can watch us live on Universe Today, or the Weekly Space Hangout YouTube page – Please subscribe!

Posted on by Evan Gough

Watch the Sun to Know When We’re Going to Have Killer Auroras

The darker area on this image of the Sun's surface is the southern extension of the northern hemisphere polar corona. The coronal hole is a source of fast-moving streams of particles from the Sun, which can cause auroras here on Earth. Image: NASA/SDO

To the naked eye, the Sun puts out energy in a continual, steady state, unchanged through human history. (Don’t look at the sun with your naked eye!) But telescopes tuned to different parts of the electromagnetic spectrum reveal the Sun’s true nature: A shifting, dynamic ball of plasma with a turbulent life. And that dynamic, magnetic turbulence creates space weather.

Space weather is mostly invisible to us, but the part we can see is one of nature’s most stunning displays, the auroras. The aurora’s are triggered when energetic material from the Sun slams into the Earth’s magnetic field. The result is the shimmering, shifting bands of color seen at northern and southern latitudes, also known as the northern and southern lights.

This image of the northern lights over Canada was taken by a crew member on board the ISS in Sept. 2017. Image: NASA

There are two things that can cause auroras, but both start with the Sun. The first involves solar flares. Highly-active regions on the Sun’s surface produce more solar flares, which are sudden, localized increase in the Sun’s brightness. Often, but not always, a solar flare is coupled with a coronal mass ejection (CME).

A coronal mass ejection is a discharge of matter and electromagnetic radiation into space. This magnetized plasma is mostly protons and electrons. The CME ejection often just disperses into space, but not always. If it’s aimed in the direction of the Earth, chances are we get increased auroral activity.

The second cause of auroras are coronal holes on the Sun’s surface. A coronal hole is a region on the surface of the Sun that is cooler and less dense than surrounding areas. Coronal holes are the source of fast-moving streams of material from the Sun.

Whether it’s from an active region on the Sun full of solar flares, or whether it’s from a coronal hole, the result is the same. When the discharge from the Sun strikes the charged particles in our own magnetosphere with enough force, both can be forced into our upper atmosphere. As they reach the atmosphere, they give up their energy. This causes constituents in our atmosphere to emit light. Anyone who has witnessed an aurora knows just how striking that light can be. The shifting and shimmering patterns of light are mesmerizing.

The auroras occur in a region called the auroral oval, which is biased towards the night side of the Earth. This oval is expanded by stronger solar emissions. So when we watch the surface of the Sun for increased activity, we can often predict brighter auroras which will be more visible in southern latitudes, due to the expansion of the auroral oval.

This photo is of the aurora australis over New Zealand. Image: Paul Stewart, Public Domain, CC 1.0 Universal.

Something happening on the surface of the Sun in the last couple days could signal increased auroras on Earth, tonight and tomorrow (March 28th, 29th). A feature called a trans-equatorial coronal hole is facing Earth, which could mean that a strong solar wind is about to hit us. If it does, look north or south at night, depending on where your live, to see the auroras.

Of course, auroras are only one aspect of space weather. They’re like rainbows, because they’re very pretty, and they’re harmless. But space weather can be much more powerful, and can produce much greater effects than mere auroras. That’s why there’s a growing effort to be able to predict space weather by watching the Sun.

A powerful enough solar storm can produce a CME strong enough to damage things like power systems, navigation systems, communications systems, and satellites. The Carrington Event in 1859 was one such event. It produced one of the largest solar storms on record.

That storm occurred on September 1st and 2nd, 1859. It was preceded by an increase in sun spots, and the flare that accompanied the CME was observed by astronomers. The auroras caused by this storm were seen as far south as the Caribbean.

Sunspots are dark areas on the surface of the Sun that are cooler than the surrounding areas. They form where magnetic fields are particularly strong. The highly active magnetic fields near sunspots often cause solar flares. Image: NASA/SDO/AIA/HMI/Goddard Space Flight Center

The same storm today, in our modern technological world, would wreak havoc. In 2012, we almost found out exactly how damaging a storm of that magnitude could be. A pair of CMEs as powerful as the Carrington Event came barreling towards Earth, but narrowly missed us.

We’ve learned a lot about the Sun and solar storms since 1859. We now know that the Sun’s activity is cyclical. Every 11 years, the Sun goes through its cycle, from solar maximum to solar minimum. The maximum and minimum correspond to periods of maximum sunspot activity and minimum sunspot activity. The 11 year cycle goes from minimum to minimum. When the Sun’s activity is at its minimum in the cycle, most CMEs come from coronal holes.

NASA’s Solar Dynamics Observatory (SDO), and the combined ESA/NASA Solar and Heliospheric Observatory (SOHO) are space observatories tasked with studying the Sun. The SDO focuses on the Sun and its magnetic field, and how changes influence life on Earth and our technological systems. SOHO studies the structure and behavior of the solar interior, and also how the solar wind is produced.

Several different websites allow anyone to check in on the behavior of the Sun, and to see what space weather might be coming our way. The NOAA’s Space Weather Prediction Center has an array of data and visualizations to help understand what’s going on with the Sun. Scroll down to the Aurora forecast to watch a visualization of expected auroral activity.

NASA’s Space Weather site contains all kinds of news about NASA missions and discoveries around space weather. SpaceWeatherLive.com is a volunteer run site that provides real-time info on space weather. You can even sign up to receive alerts for upcoming auroras and other solar activity.

Posted on by Matt Williams

Try to Contain Your Surprise. James Webb is Getting Delayed to 2020

Illustration of NASA's James Webb Space Telescope. Credits: NASA
Illustration of NASA's James Webb Space Telescope. Credits: NASA

Once it deploys, the James Webb Space Telescope (JWST) will be the most powerful and technically complex space telescope ever deployed. Using its powerful suite of infrared-optimized instruments, this telescope will be able to study the earliest stars and galaxies in the Universe, extra-solar planets around nearby stars, and the planets, moons and asteroids of our Solar System.

Unfortunately, due to its complexity and the need for more testing, the launch of the JWST has been subject to multiple delays. And as of this morning, NASA announced that the launch JWST has been delayed yet again. According to a statement issued by the agency, the launch window for the JWST is now targeted for sometime around May 2020.

The decision came after an independent assessment by the project’s Standing Review Board (SRB) of the remaining tasks, all of which are part of the final stage of integration and testing before the JWST launches. These tasks consist of integrating the combined optics and science instruments onto the spacecraft element, then testing them to ensure that they will deploy properly and work once they are in space.

The Space Telescope for Air, Road, and Sea (STTARS) is a custom-designed container that holds the James Webb’s Optical Telescope and Integrated Science (OTIS) instrument module. In this image its being unloaded from a U.S. military C-5 Charlie aircraft at Los Angeles International Airport (LAX) on Feb. 2, 2018. Image: NASA/Chris Gunn

This assessment came on the heels of a report issued by the Government Accountability Office (GAO) in February that expressed concerns over further delays and cost overruns. These concerns were based on the fact that it is typically in the final phase when problems are found and schedules revised, and that only 1.5 months of schedule reserved remained (at the time) until the end of the telescope’s launch window – which was scheduled for 2019.

But as acting NASA Administrator Robert Lightfoot stressed, the JWST is still a go:

“Webb is the highest priority project for the agency’s Science Mission Directorate, and the largest international space science project in U.S. history. All the observatory’s flight hardware is now complete, however, the issues brought to light with the spacecraft element are prompting us to take the necessary steps to refocus our efforts on the completion of this ambitious and complex observatory.”

NASA also announced that it is establishing an external Independent Review Board (IRB) chaired by Thomas Young – a highly-respected NASA and industry veteran who has a long history of chairing advisory committees and analyzing organizational and technical issues. The IRB findings, along with the SRB data, will be considered by NASA to set a more specific launch date, and will be presented to Congress this summer.

In the meantime, NASA and the European Space Agency (ESA) will be setting a new launch readiness date for the Ariane 5 rocket that will bring the JWST into space. Once a launch date is set, NASA will also be providing a cost estimate that may exceed the $8 billion budget cap established by Congress in 2011. This too is in keeping with the GAO’s report, which predicted cost overruns.

The Space Telescope Transporter for Air, Road and Sea (STTARS) being opened at Northrop Grumman on March 8th, 2018, to reveal the combined optics and science instruments of NASA’s James Webb Space Telescope. Credits: NASA/Chris Gunn

For those who have been following the JWST’s development, this news should come as no surprise. Due to its complexity and the need for extensive testing, the launch of the JWST has been delayed several times in recent years. In addition, the final phase consists of some of the most challenging work, where the 6.5-meter telescope and science payload element are being joined with the spacecraft element to complete the observatory.

In addition, the science team also needs to ensure that the observatory can be folded up to fit inside the Ariane 5 rocket that will launch it into space. They also need to ensure that it will unfold again once it reaches space, deploying its sunshield, mirrors and primary mirror. Beyond that, there are also the technical challenges of building a complex observatory that was created here on Earth, but designed to operate in space.

Not only does all of this represent a very technically-challenging feet, it is the first time that any space telescope has had to perform it. Already, the JWST has completed an extensive range of tests to ensure that it will reach its orbit roughly 1.6 million km (1 million mi) from Earth. And while delays can be discouraging, they also increase the likelihood of mission success.

As Thomas Zurbuchen, the associate administrator for NASA’s Science Mission Directorate, stated:

“Considering the investment NASA and our international partners have made, we want to proceed systematically through these last tests, with the additional time necessary, to be ready for a May 2020 launch.”

The combined optics and science instruments of NASA’s James Webb Space Telescope being removed from the Space Telescope Transporter for Air, Road and Sea (STTARS) at the Northrop Grumman company headquarters on March 8th, 2018. Credits: NASA/Chris Gunn

The next step in testing will take several months, and will consist of the spacecraft element undergoing tests to simulate the vibrational, acoustic and thermal environments it will experience during its launch and operations. Once complete, the project engineers will integrate and test the fully assembled observatory and verify that all its components work together properly.

And then (fingers crossed!) this ambitious telescope will finally be ready to take to space and start collecting light. In so doing, scientists from all around the world hope to shed new light on some of the most fundamental questions of science – namely, how did the Universe evolve, is their life in our Solar System beyond Earth, are their habitable worlds beyond our Solar System, and are there other civilizations out there?

Bottom line, NASA remains committed to deploying the James Webb Space Telescope. So even if the answers to these questions are delayed a little, they are still coming!

Further Reading: NASA

Posted on by Matt Williams

NASA’s Curiosity Rover Enjoys its 2000th Day on Mars

This mosaic taken by NASA's Mars Curiosity rover looks uphill at Mount Sharp, which Curiosity has been climbing since 2014. Highlighted in white is an area with clay-bearing rocks that scientists are eager to explore; it could shed additional light on the role of water in creating Mount Sharp. Credit: NASA/JPL-Caltech/MSSS

Since it landed on Mars in 2012, the Curiosity rover has made some rather startling scientific discoveries. These include the discovery of methane and organic molecules, evidence of how it lost its ancient atmosphere, and confirming that Mars once had flowing water and lakes on its surface. In addition, the rover has passed a number of impressive milestones along the way.

In fact, back in January of 2018, the rover had spent a total of 2,000 Earth days on Mars. And as of March 22nd, 2018, NASA’s Mars Curiosity rover had reached its two-thousandth Martian day (Sol) on the Red Planet! To mark the occasion, NASA released a mosaic photo that previews what the rover will be investigating next (hint: it could shed further light on whether or not Mars was habitable in the past).

The image (shown at top and below) was assembled from dozens of images taken by Curiosity‘s Mast Camera (Mastcam) on Sol 1931 (back in January). To the right, looming in the background, is Mount Sharp, the central peak in the Gale Crater (where Curiosity landed back in 2012). Since September of 2014, the rover has been climbing this feature and collecting drill samples to get a better understanding of Mars’ geological history.

Image of the mosaic taken by NASA’s Mars Curiosity rover in January of 2018 (Sol 1931). Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

In the center of the image is the rover’s next destination and scientific target. This area, which scientists have been studying from orbit, is rich in clay minerals, which indicates that water once existed there. In the past, the Curiosity rover found evidence of clay minerals on the floor of the Gale Crater. This confirmed that the crater was a lake bed between 3.3 and 3.8 billion years ago.

Mount Sharp, meanwhile, is believed to have formed from sedimentary material that was deposited over a period of about 2 billion years. By examining patches of clay minerals that extend up the mountain’s side, scientists hope to gain insight into the history of Mars since then. These include how long water may have persisted on its surface and how the planet made the transition to the cold and desiccated place it is today.

The Curiosity science team is eager to analyze rock samples pulled from the clay-bearing rocks seen in the center of the image, and not just because of the results they could provide. Recently, the science team developed a new drilling technique to compensate for the failure of a faulty motor (which allows the drill to extend and retract). When the rover begins to drill again, it will be the first time since December 2016.

All told, the rover has spent a total of about 2055 Earth days (5 years and 230 days), which means Curiosity now ranks third behind the Opportunity (5170 days; 5031 sols) and the Spirit rovers (2269 days; 2208 sols) in terms of total time spent on Mars. Since it arrived on Mars in 2012, Curiosity has also traveled a total distance of 18.7 km (11.6 mi) and studied more than 180 meters (600 feet) vertical feet of rock.

But above all, Curiosity‘s greatest achievement has been the discovery that Mars once had all the necessary conditions and chemical ingredients to support microbial life. Based on their findings, Curiosity‘s international science team has concluded that habitable conditions must have lasted for at least millions of years before Mars’ atmosphere was stripped away.

Finding the evidence of this, and how the transition occurred, will not only advance our understanding of the history of Mars, but of the Solar System itself. It also might provide clues as to how Mars could be made into a warmer, wetter environment again someday!

Further Reading: NASA

Posted on by Susie Murph

Astronomy Cast Ep. 484: Transfer Orbits and Gravitational Assists

If you want to get around in the Solar System, you’ll want to take advantage of natural gravitational speed boosts and transfer orbits. Whether you’re heading to the outer Solar System or you want to visit the Sun itself, the planets themselves can help you in your journey.

We usually record Astronomy Cast every Friday at 3:00 pm EST / 12:00 pm PST / 20:00 PM UTC. You can watch us live on AstronomyCast.com, or the AstronomyCast YouTube page.

Visit the Astronomy Cast Page to subscribe to the audio podcast!

If you would like to support Astronomy Cast, please visit our page at Patreon here – https://www.patreon.com/astronomycast. We greatly appreciate your support!

If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!

Posted on by Matt Williams

Wow, Elon Musk Just Deleted the Facebook Pages for SpaceX and Tesla

And Liftoff for Falcon Heavy. Credit: SpaceX
And Liftoff for Falcon Heavy. Credit: SpaceX

About a week ago, it was revealed that the roughly 50 million Facebook profiles were harvested by Cambridge Analytica. This private data firm, which worked with Donald Trump’s election team and the Brexit campaign, reportedly used this data build a software program that could predict and influence voter choices. Since that time, Facebook stock has taken a serious hit, investigations have been mounted, and CEO Mark Zuckerberg himself has come under fire.

In addition, this revelation has led many Facebook users to reconsider their privacy settings or cancel their accounts. One such person is Elon Musk. In a move that could prove rather harmful for the social media giant, Musk recently responded to the news by deleting the official Facebook pages for Tesla and SpaceX. And in a rather ironic twist, the announcement came via another social media giant – Elon Musk’s twitter account.

It all began after Musk responded to a tweet posted by Brian Acton, the famed programmer and entrepreneur who co-founded WhatsApp and is the founder of Signal (an encrypted communications app). In what was clearly an act of jest, he responded to Acton’s statement (“It is time”) and use of the trending hashtag (#deletefacebook), by inquiring “What’s Facebook?”

Naturally, no one was buying it, given that SpaceX and Facebook – and their respective CEOs) – have a rather colorful history of business relations. These include the failed launch that took place in September of 2016, where a Falcon 9 carrying a Israeli telecommunications satellite (which would have also been used by Facebook) exploded on the launch pad.

In response to the news, Zuckerberg posted a statement on Facebook that placed the blame for the failed launch squarely on Musk’s company:

“As I’m here in Africa, I’m deeply disappointed to hear that SpaceX’s launch failure destroyed our satellite that would have provided connectivity to so many entrepreneurs and everyone else across the continent.”

This old grudge was also raised on Twitter amidst the discussion about Facebook’s data breach, with a user reminding everyone about the incident. Musk brushed this aside, tweeting, “Yeah, my fault for being an idiot. We did give them a free launch to make up for it and I think they had some insurance.”

This led to a challenge being issued to Musk, where users wrote him and urged him to delete his company’s accounts. In what was arguably an attempt to keep the joke going, Musk responded by indicating that he didn’t know these accounts existed. He did, however, also promise to remove the accounts forthwith.

And it appears that Musk was true to his word. While SpaceX and Tesla still have Facebook pages and show up in searches, the official accounts appear to be gone. Musk chose to maintain the company’s official Instagram account though, and used the opportunity to once again stress that he had little use for Facebook:

“Instagram’s probably ok imo, so long as it stays fairly independent. I don’t use FB & never have, so don’t think I’m some kind of martyr or my companies are taking a huge blow. Also, we don’t advertise or pay for endorsements, so … don’t care.”

Well, martyr or not, Musk appears to have put his money where his mouth is. And of course, his twitter feed is still going strong and there is no indication he plans on turning that off anytime soon! And whether this was intended as as slight to Zuckerberg or a sincere expression of indifference, it is likely that Musk’s move could prompt more users to delete their accounts.

But of course, the social media giant will survive. And given Zuckerberg‘s and Musk‘s competing visions to provide global broadband internet access using satellites, its a certainty that the two entrepreneurs are not done with each other!

Further Reading: Futurism, Twitter

Posted on by Matt Williams

About 2.3 Billion Years Ago, a Firehose of Oxygen was Released Into the Atmosphere

Salts left over from ancient seawater reveal new information about the oxygenation of the Earth’s atmosphere more than 2 billion years ago. Shown here is a sample of 2-billion-year-old salt (pink-white recrystallized halite) with embedded fragments of calcium sulfate from a geological drill core in Russian Karelia. Credit: Aivo Lepland, Geological Survey of Norway; courtesy of Science/AAAS

Billions of years ago, Earth’s environment was very different from the one we know today. Basically, our planet’s primordial atmosphere was toxic to life as we know it, consisting of carbon dioxide, nitrogen and other gases. However, by the Paleoproterozoic Era (2.5–1.6 billion years ago), a dramatic change occurred where oxygen began to be introduced to the atmosphere – known as the Great Oxidation Event (GOE).

Until recently, scientists were not sure if this event – which was the result of photosynthetic bacteria altering the atmosphere – occurred rapidly or not. However, according to a recent study by a team of international scientists, this event was much more rapid than previously thought. Based on newly-discovered geological evidence, the team concluded that the introduction of oxygen to our atmosphere was “more like a fire hose” than a trickle.

Continue reading “About 2.3 Billion Years Ago, a Firehose of Oxygen was Released Into the Atmosphere”
Posted on by Bob King

NASA’s Parker Solar Probe Will Touch the Sun — So Can You

Credit: NASA

NASA’s Parker Solar Probe will launch this summer and study both the solar wind and unanswered questions about the Sun’s sizzling corona. Credit: NASA

How would you like to take an all-expenses-paid trip to the Sun? NASA is inviting people around the world to submit their names to be placed on a microchip aboard the Parker Solar Probe mission that will launch this summer. As the spacecraft dips into the blazing hot solar corona your name will go along for the ride. To sign up, submit your name and e-mail. After a confirming e-mail, your digital “seat” will be booked. You can even print off a spiffy ticket. Submissions will be accepted until April 27, so come on down!

Step right up! Head over before April 27 to put a little (intense) sunshine in your life. Click the image to go there. Credit: NASA

The Parker Solar Probe is the size of a small car and named for Prof. Eugene Parker, a 90-year-old American astrophysicist who in 1958 discovered the solar wind. It’s the first time that NASA has named a spacecraft after a living person. The Parker probe will launch between July 31 and August 19 but not immediately head for the Sun. Instead it will make a beeline for Venus for the first of seven flybys. Each gravity assist will slow the craft down and reshape its orbit (see below), so it later can pass extremely close to the Sun. The first flyby is slated for late September.

When heading to faraway places, NASA typically will fly by a planet to increase the spacecraft’s speed by robbing energy from its orbital motion. But a probe can also approach a planet on a different trajectory to slow itself down or reconfigure its orbit.

The spacecraft will swing well within the orbit of Mercury and more than seven times closer than any spacecraft has come to the Sun before. When closest at just 3.9 million miles (6.3 million km), it will pass through the Sun’s outer atmosphere called the corona and be subjected to temperatures around 2,500°F (1,377°C). The primary science goals for the mission are to trace how energy and heat move through the solar corona and to explore what accelerates the solar wind as well as solar energetic particles.

The Parker Solar Probe will use seven Venus flybys over nearly seven years to gradually shrink its orbit around the Sun, coming as close as 3.7 million miles (5.9 million km), well within the orbit of Mercury. Closest approaches (called perihelia) will happen in late December 2024 and the first half of 2025 before the mission ends. Credit: NASA

The vagaries of the solar wind, a steady flow of particles that “blows” from the Sun’s corona at more than million miles an hour, can touch Earth in beautiful ways as when it energizes the aurora borealis. But it can also damage spacecraft electronics and poorly protected power grids on the ground. That’s why scientists want to know more about how the corona works, in particular why it’s so much hotter than the surface of the Sun — temperatures there are several million degrees.

During the probe’s closest approach, the Sun’s apparent diameter will span 14° of sky. Compare that to the ½° Sun we see from Earth. Can you imagine how hot the Sun’s rays would be if it were this large from Earth? Life as we know it would be over. Wikipedia / CC BY-SA 3.0

As you can imagine, it gets really, really hot near the Sun, so you’ve got to take special precautions. To perform its mission, the spacecraft and instruments will be protected from the Sun’s heat by a 4.5-inch-thick carbon-composite shield, which will keep the four instrument suites designed to study magnetic fields, plasma and energetic particles, and take pictures of the solar wind, all at room temperature.

Similar to how the Juno probe makes close passes over Jupiter’s radiation-fraught polar regions and then loops back out to safer ground, the Parker probe will make 24 orbits around the Sun, spending a relatively short amount of face to face time with our star. At closest approach, the spacecraft will be tearing along at about 430,000 mph, fast enough to get from Washington, D.C., to Tokyo in under a minute, and will temporarily become the fastest manmade object. The current speed record is held by Helios-B when it swung around the Sun at 156,600 mph (70 km/sec) on April 17, 1976.

A composite of the August 21, 2017 total solar eclipse showing the Sun’s spectacular corona. Astronomers still are sure why it’s so much hotter than the 10,000°F solar surface (photosphere). Theories include a microflares or magnetic waves that travel up from deep inside the Sun. Credit and copyright: Alan Dyer / amazingsky.com

Many of you saw last August’s total solar eclipse and marveled at the beauty of the corona, that luminous spider web of light around Moon’s blackened disk. When closest to the Sun at perihelion the Parker probe will fly to within 9 solar radii (4.5 solar diameters) of its surface. That’s just about where the edge of the furthest visual extent of the corona merged with the blue sky that fine day, and that’s where Parker will be!