The research relied on data from STEREO, a NASA mission that has been orbiting the sun since 2006. It carries an instrument called a coronagraph, which uses a black disk to block out the bright surface of the sun. That lets scientists see what's happening in the corona, which is much fainter than the surface and would otherwise be washed out by its light.

But that data hasn't been detailed enough to let scientists see what's really happening inside the corona, according to NASA. To tackle that problem, the researchers first asked for a specific type of data from the STEREO team: long-exposure images that would capture fainter signals. Then, they set to work laboriously cleaning up the data to remove confusing factors like the light of background stars or false signals from the instrument itself.

The cleanup involved piecing together the images in a particularly careful way that considered how quickly the solar wind was flowing out and shifting the images accordingly. To do so, they matched up images over time, according to their place in the flow of solar wind, rather than their specific location in space — like tracking individual patches of solar wind as they streamed out of the sun.

The process is the equivalent of aligning sequential images of a log drifting in a current so that the log, rather than the trees along the riverbank, stacks up in every image — offering a more detailed image of the log.

The result is a much clearer picture of the flow of solar wind, showing the smaller structures that make up the seemingly disorganized whole. That structure, hidden below the smooth surface, helps explain why the solar wind flows so turbulently as it travels farther away from the sun.

The research is described in a paper published in The Astrophysical Journal on July 18.

The new imaging also highlighted a region where things got particularly interesting, about 4.3 million miles (7 million kilometers) above the sun's surface. Before and after this point, the solar wind was relatively easy to track, but in this region, the flow seemed to hit a bump in the road. The team isn't sure what's happening there.

Conveniently enough, NASA is due to launch a new mission that will bring scientists even more data about the sun's corona. The Parker Solar Probe, scheduled for launch in early August with data collection beginning later this year, will eventually fly directly through this region of our star, dipping below the bumpy section — and hopefully deciphering still more mysteries about the solar wind and its birthplace.

• Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels.
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• Original article on Space.com.

July's total lunar eclipse occurs on the same day the planet Mars reaches its opposition, when it will shine at its best in the night sky. This month, Mars will be at its closest to Earth since 2003. After opposition, when Mars will be brightest, it will reach that closest point on July 31. You can learn more about that event in our dedicated guide here: Mars at Opposition 2018: How to See It and What to Expect

What is the Blood Moon of July 27?

Unlike with solar eclipses, you need no special equipment to observe lunar eclipses. These latter events, which occur when the moon passes into Earth's shadow, are safe to view directly with the naked eye, telescopes or binoculars.

The moon turns deep red or reddish brown during eclipses, instead of going completely dark. That's because some of the sunlight going through Earth's atmosphere is bent around the edge of our planet and falls onto the moon's surface. Earth's air also scatters more shorter-wavelength light (in colors such as green or blue); what's left is the longer-wavelength, redder end of the spectrum.

Where and when will it be visible?

The timing if this total lunar eclipse means it won't be visible from North America, though much of the Eastern Hemisphere of Earth will see part or all of the eclipse. The entire eclipse will be visible from Africa, the Middle East and countries in central Asia. The eclipse will be visible from eastern South America as it is ending, and from Australia as it is beginning.

The time of greatest eclipse will be 4:21 p.m. EDT (2021 GMT) on July 27, according to EarthSky.org. The total eclipse will last from 3:30 p.m. to 5:13 p.m. EDT (1930 to 2113 GMT). There will also be some time before and after when the moon is in the lighter part of Earth's shadow, which is called the penumbra. Including that penumbral time, the eclipse will last for 3 hours and 55 minutes.

Why is it the longest of the century?

"What controls the duration of the lunar eclipse is the position of the moon as it passes through the Earth's shadow," Petro told Space.com. The darkest part of Earth's shadow is called the umbra. You can picture the umbra as a cone extending from Earth in the opposite direction to the sun, Petro explained.

"The moon can either graze through the cone, or go right through the middle. That [the middle] gets a longer-duration eclipse," he said. "This time, the moon is passing closer to the center of that cone, and it's therefore a little bit longer than the eclipse we had back in January."

Additionally, the moon will be at a farther point from Earth along its orbit, EarthSky pointed out. That means the moon will appear slightly smaller in the sky and will take a little bit longer to go through Earth's shadow.

Petro is also the project scientist for NASA's Lunar Reconnaissance Orbiter(LRO), which has been orbiting the moon for nine years. It is best-known for obtaining detailed information on water ice and taking high-resolution pictures of spacecraft on the lunar surface. Because LRO is an older probe, most of its components (except for battery warmers and the like) will be turned off during the eclipse, to preserve the solar-powered spacecraft's battery and keep it safe during the greatest part of the eclipse, Petro said.

When is the next lunar eclipse?

The next total lunar eclipse visible from North America will occur on Jan. 21, 2019. Totality on that day will last 1 hour and 2 minutes, and the eclipse will especially favor viewers on the West Coast. That year will also see a partial eclipse, on July 16, 2019 — the 50th anniversary of the launch of the first moon landing mission, Apollo 11. LRO will likely still be operating then, having passed its 10th anniversary of arriving at the moon on June 23, 2019.

Turning the Moon Blood Red

Editor's note: If you capture an amazing photo or video of the total lunar eclipse or any other night-sky sight and would like to share it with Space.com for a story or gallery, send images and comments to spacephotos@space.com. 

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  • Originally published on Space.com.

But recently, scientists have been able to study many more young solar systems, and they've realized that, early in their lives, their outer edges can be more developed than expected. That means that an early flyby could still do the trick when it comes to explaining our solar system's oddities.

So, the team behind the new research ran a set of simulations to see how likely it was that a neighboring star might have snuck past our solar system in just such a way that it explains what we see today.

That calculation is pretty promising, and the researchers claim such a model may explain all the weird qualities of the outer solar system. The research is described in a recent paper posted to the preprint server arXiv.org.

Next, the team wants to keep testing the hypothesis, making their models more detailed and exploring more details of how the region could have responded to such a close approach.

• Email Meghan Bartels at mbartels@space.com or follow her @meghanbartels.
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• Original article on Space.com.

New Frontiers was a program NASA created in 2003 for medium-sized missions that are capped at $1 billion in development and launch costs each. (The Curiosity rover, by contrast, cost about $2.5 billion.) Two finalists are in the running for the fourth New Frontiers mission — a Titan probe and a sample return probe for Comet 67P/Churyumov-Gerasimenko (the target for Europe's past Rosetta mission.)

The National Research Council identified a Jupiter orbiter as a scientific priority in 2003 in its decadal survey, "New Frontiers in the Solar System: An Integrated Exploration Strategy." Among the questions raised at the time were:

• Does Jupiter have a central core, which will help narrow down how the planet was formed?
• How much water is in its atmosphere, which helps researchers understand how big planets were created?
• How it is possible that giant weather systems remain so stable?
• What is the nature of the magnetic field and plasma surrounding Jupiter?

Juno was selected in 2005 and was originally expected to launch in June 2009, but was delayed until August 2011 due to NASA budgetary restrictions.

The team decided to take advantage of the "unusually long Phase B" (a planning phase) to find and reduce the risks to the spacecraft's development. With three years to work with instead of the usual one, they hoped to avoid design changes late in the game, communication gaps and other matters.

Launch and in-flight maneuvers

Juno launched from Cape Canaveral Air Force Station on Aug. 5, 2011. While eight other spacecraft have flown in Jupiter's neighborhood in decades past, part of what makes Juno stand apart is its ability to generate solar power from Jupiter's neighborhood. The other spacecraft relied on nuclear power, but the reserves for plutonium generation have dwindled for NASA in recent decades.

"Solar power is possible on Juno due to improved solar-cell performance, energy-efficient instruments and spacecraft, a mission design that can avoid Jupiter's shadow, and a polar orbit that minimizes the total radiation," wrote NASA in 2016, when Juno broke a solar distance record for all spacecraft. (The previous record-holder was Rosetta, which arrived at Comet 67P — beyond the orbit of Mars — in 2014.)

Before setting out for Jupiter for good, Juno earned a speed boost of more than 8,800 mph (3.9 kilometers per second) when it flew by Earth on Oct. 9, 2013. The spacecraft took images of our planet (it reminded principal investigator Scott Bolton of Star Trek imagery) and also listened in on amateur radio signals as part of an outreach effort with ham radio operators.

In February 2016, the Juno spacecraft did a maneuver to put in on course for the gas giant for a July 4, 2016, arrival. Independence Day has been an auspicious date for NASA spacecraft arrival in the past. Examples include the Mars Pathfinder and Sojourner mission arrival at the Red Planet (1997) and Deep Impact's planned collision with Comet Tempel 1 (2005). 

Viking 1, NASA's first lander on Mars, was also supposed to touch down on July 4, 1976, but when the spacecraft got closer, pictures revealed the landing site was too rough for a landing. Viking 1 successfully landed at an alternate site on July 20, 1976, seven years to the day after the first human moon landing.

[Infographic: How NASA's Juno Mission to Jupiter Works]

Science goals

Several spacecraft have flown by Jupiter en route to other locations in the solar system (such as Pioneer 10 and 11, Voyager 1 and 2, and New Horizons). Even during the brief flybys, they have been able to glimpse interesting information about Jupiter and its moons. For example, New Horizons caught a large outburst on the volcanic moon Io. 

To date, however, only one mission stayed for the long term: Galileo. After being launched from space shuttle Atlantis in October 1989, Galileo arrived at Jupiter in 1995 and spent eight years studying the planet and its moons. 

Galileo's discoveries include finding potential salt-water oceans under the crusts of Europa, Callisto and Ganymede. It also sent a descent probe into Jupiter's atmosphere. Much of the mission's value also came from spending nearly a decade in Jupiter's system, allowing scientists the rare chance to do up-close, lengthy observations of the largest planet in the solar system.

Juno focuses solely on Jupiter and is trying to answer at least some of the following questions, according to NASA:

• How much water does Jupiter have in its atmosphere? This is important to figure out if our formation theories of the solar system are correct, or if they need some work.
• What is Jupiter's atmosphere like? Specifically, what are the properties at every layer such as gas composition, temperature and cloud motions? Figuring out the weather on Jupiter will help us learn more about gas giant weather generally. (It's important for planets in our solar system, as well as exoplanets.)
• What are the magnetic and gravity fields of Jupiter? This will give scientists some hints of what the interior structure of Jupiter looks like.
• How does the magnetic environment of Jupiter affect its atmosphere? Part of that study will come through looking at auroras.

Initial Juno observations

During Juno's calibration phase in August 2016, the spacecraft discovered that the famous bands around the planet extend deep into the atmosphere.

In February 2017, NASA announced that Juno would remain in its current, 53-day orbit throughout the rest of the mission. Managers initially had planned to alter the orbit so that Juno came closer to the planet, but indicated they were concerned that – given the spacecraft had trouble with helium valves in its engine – firing the main engine may result in a "less than desirable orbit." 

A view from Juno in May 2017 showed the rings as never glimpsed before. Jupiter, like all the gas giants in the solar system, has rings – but they are much less spectacular than those at Saturn. Juno's picture was the first to show Jupiter's rings from an inside point of view. 

The team also revealed that particles powering Jupiter's auroras appear to be different than those that make Earth's auroras glow. Also, the poles feature gigantic cyclones, and none of the zones and belts that are visible at more equatorial latitudes. High-altitude clouds appear to be snowing material in the upper atmosphere. Even more weirdly, the core appears larger and more diffuse than scientists previously anticipated, which has implications for our understanding of how Jupiter formed.

Juno took many images of Jupiter's iconic Great Red Spot — a gigantic storm — in July 2017. Scientists are interested in why the storm persisted for so long, and why it has been shrinking for the past several decades.

Meanwhile, citizen scientists continue participating through the JunoCam instrument, which takes pictures for people to process on their own time. Some examples of collaborations include a picture of moons Io and Europa in October 2017 and a stunning view of Jupiter's clouds released in September that year.

Moving into an extended mission

In June 2018, NASA announced it would extend the Juno mission until at least July 2021 to allow scientists to do more data analysis. At the time, the extension was billed as allowing scientists to follow up on some of the interesting questions Juno had raised so far.

The announcement also discussed several intriguing Juno findings pointing to trends in Jupiter's long-term weather and atmospheric features. Earlier that year, around the same time the Juno team released several new picturesshowing colorful atmospheric bands stretching across the planet, Bolton told reporters that scientists had been "totally wrong" about Jupiter before Juno arrived.
"Our ideas were totally wrong about the interior structure, about the atmosphere, [and] even about the magnetosphere," said Bolton at the 231st meeting of the American Astronomical Society on Jan. 9, 2018.

Examples include Juno finding a huge "fuzzy" core instead of the small and dense core investigators expected, weird groups of cyclones at Jupiter's north and south poles, auroras powered by a source that astronomers can't find, and odd behavior in its magnetic field.

In late 2017, Juno also revealed that the Great Red Spot are at least 50 times deeper than the Earth's oceans. "Juno found that the Great Red Spot's roots go 50 to 100 times deeper than Earth's oceans and are warmer at the base than they are at the top," said Andy Ingersoll, a professor of planetary science at Caltech and a Juno co-investigator, at the time. "Winds are associated with differences in temperature, and the warmth of the spot's base explains the ferocious winds we see at the top of the atmosphere."