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Retired Canadian Astronaut & Author
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Why the Parker Solar Probe is NASA's most exciting mission

Michelle Thaller: One of the most exciting things that's going on at NASA right now is that we have a probe that's actually orbiting very close to the sun. And over the next years, it's going to get closer, and closer, and closer. It's called the Parker Solar Probe, and the catch phrase, sort of the mission motto is, a mission to touch the sun. And that sounds incredibly dramatic. I should probably quantify that a bit. We're not actually touching the surface of the Sun, but the Sun has an atmosphere of gas around it, almost like the Earth has an atmosphere. It's called the corona. And the corona extends many millions of miles away from the surface of the Sun. Parker Solar Probe is actually going to fly through the Corona, getting into a fairly close part.

Now, it doesn't sound so close. It's going to get within about four million miles away from the Sun. But the Sun itself is nearly a million miles across. It's about 900,000 miles across. So this is actually getting just about four times the diameter of the Sun away, which is really pretty close. It's by far the closest object that humanity has ever sent to the Sun.

Over the next seven years, it's going to orbit around 24 times. And each time, it's going to get a little bit closer to the Sun. And in order to survive that, in order to have enough speed to actually escape the Sun's gravity and come out again, it's going to go faster and faster all the time as well. So at its fastest-- in a few years from now-- the Parker Solar Probe will be going nearly 400,000 miles an hour as it loops around the sun and then comes right back out again. That's by far the fastest speed that any human-made spacecraft has ever attained. And that's going to be very exciting. So each perihelion is a little closer and a little faster, and then the orbit takes it out close to the planet Venus. And the planet Venus actually-- interestingly enough-- it helps Parker lose energy. In order to get closer and closer to the Sun, Parker has to lose some of its own rotational energy. And when it loses energy, it can drop in a little closer all the time. So over the next years, you're going to see our spacecraft get a little closer each time and go a little faster each time it goes around the Sun.

Now, what are we looking for? Why are we actually flying a spacecraft this close to the Sun? Well, the corona, the atmosphere around the sun, is actually one of the biggest mysteries in our solar system. It's extremely hot. The gas around the Sun is millions of degrees. And that's rather strange because the surface of the Sun itself is only about 10,000 degrees. So how can the gas above the surface be that much hotter than the surface itself? Kind of the analogy we use at NASA is picture yourself around a campfire at night and you're enjoying the warmth of the campfire, but then as you walk away from the fire, it becomes hotter and hotter as you go away and burns you to a crisp five miles out. That doesn't work. It's a very strange way of thinking about temperature. So something's going on with the corona. It may have to do with the Sun's complex magnetic field. Maybe the magnetic field is shooting particles up into it. It may have to do with shock waves, even the Sun vibrating and actually giving energy to the gas above it. There's many different ideas and theories as to why the corona is so hot. But right now, we don't have a great way to tell which is right and which isn't. So when we're there and actually measuring how fast the particles are going, the different particles you find, how dense or how rarified that gas is around the sun, we'll have a much better idea which of those theories are true.

The Parker Solar Probe to me is also a marvel of modern engineering. I mean, think about how are you going to get a spacecraft that close to the Sun, and have it survive and not burn up. Well, the whole spaceship is protected by a heat shield. The heat shield itself is not very thick. It's actually only about six inches thick. And it's made of a carbon composite material with a very shiny reflective aluminum coating on top. Incredibly, that heat shield is still going to get up to about 2,500 degrees Fahrenheit. So it's going to get very, very hot, but that will protect the rest of the spacecraft from the radiation coming from the Sun. And the angle has to be just right. You always have to have the heat shield right in between the Sun and the rest of the spacecraft. The rest of the spacecraft has to be in its shadow, or it will fry. And we actually can't send commands up to Parker often enough to make sure it's exactly lined up. So Parker is a very autonomous spacecraft. It's constantly detecting what its angle is relative to the Sun and correcting that. So in some ways, it's one of the most autonomous spacecraft yet launched.

One of the things I think is kind of funny about the design is it does use solar power-- that makes sense-- you're very close to the Sun. But it has these really, really dinky little solar panels off to the side because when you get close to the sun, you don't need big solar panels. So at the end of Parker Solar Probe's mission, we will have this thing orbiting closer to the sun than we've ever been before, going faster than we ever have before. And maybe we'll finally have some idea why this corona, this mysterious million-degree gas around the Sun can possibly be that hot.

  • The Parker Solar Probe is set to uncover a mystery about the sun: Why is it's corona hotter than its surface?
  • NASA's ability to fly a probe so close to the sun is a marvel of engineering.
  • Michelle Thaller, an astronomer at NASA, explains why the Parker Solar Probe is so hot right now.

A new hydrogel might be strong enough for knee replacements

Duke University researchers might have solved a half-century old problem.

Photo by Alexander Hassenstein/Getty Images
Technology & Innovation
  • Duke University researchers created a hydrogel that appears to be as strong and flexible as human cartilage.
  • The blend of three polymers provides enough flexibility and durability to mimic the knee.
  • The next step is to test this hydrogel in sheep; human use can take at least three years.
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Predicting PTSD symptoms becomes possible with a new test

An algorithm may allow doctors to assess PTSD candidates for early intervention after traumatic ER visits.

Image source: camillo jimenez/Unsplash
Technology & Innovation
  • 10-15% of people visiting emergency rooms eventually develop symptoms of long-lasting PTSD.
  • Early treatment is available but there's been no way to tell who needs it.
  • Using clinical data already being collected, machine learning can identify who's at risk.

The psychological scars a traumatic experience can leave behind may have a more profound effect on a person than the original traumatic experience. Long after an acute emergency is resolved, victims of post-traumatic stress disorder (PTSD) continue to suffer its consequences.

In the U.S. some 30 million patients are annually treated in emergency departments (EDs) for a range of traumatic injuries. Add to that urgent admissions to the ED with the onset of COVID-19 symptoms. Health experts predict that some 10 percent to 15 percent of these people will develop long-lasting PTSD within a year of the initial incident. While there are interventions that can help individuals avoid PTSD, there's been no reliable way to identify those most likely to need it.

That may now have changed. A multi-disciplinary team of researchers has developed a method for predicting who is most likely to develop PTSD after a traumatic emergency-room experience. Their study is published in the journal Nature Medicine.

70 data points and machine learning

nurse wrapping patient's arm

Image source: Creators Collective/Unsplash

Study lead author Katharina Schultebraucks of Columbia University's Department Vagelos College of Physicians and Surgeons says:

"For many trauma patients, the ED visit is often their sole contact with the health care system. The time immediately after a traumatic injury is a critical window for identifying people at risk for PTSD and arranging appropriate follow-up treatment. The earlier we can treat those at risk, the better the likely outcomes."

The new PTSD test uses machine learning and 70 clinical data points plus a clinical stress-level assessment to develop a PTSD score for an individual that identifies their risk of acquiring the condition.

Among the 70 data points are stress hormone levels, inflammatory signals, high blood pressure, and an anxiety-level assessment. Says Schultebraucks, "We selected measures that are routinely collected in the ED and logged in the electronic medical record, plus answers to a few short questions about the psychological stress response. The idea was to create a tool that would be universally available and would add little burden to ED personnel."

Researchers used data from adult trauma survivors in Atlanta, Georgia (377 individuals) and New York City (221 individuals) to test their system.

Of this cohort, 90 percent of those predicted to be at high risk developed long-lasting PTSD symptoms within a year of the initial traumatic event — just 5 percent of people who never developed PTSD symptoms had been erroneously identified as being at risk.

On the other side of the coin, 29 percent of individuals were 'false negatives," tagged by the algorithm as not being at risk of PTSD, but then developing symptoms.

Going forward

person leaning their head on another's shoulder

Image source: Külli Kittus/Unsplash

Schultebraucks looks forward to more testing as the researchers continue to refine their algorithm and to instill confidence in the approach among ED clinicians: "Because previous models for predicting PTSD risk have not been validated in independent samples like our model, they haven't been adopted in clinical practice." She expects that, "Testing and validation of our model in larger samples will be necessary for the algorithm to be ready-to-use in the general population."

"Currently only 7% of level-1 trauma centers routinely screen for PTSD," notes Schultebraucks. "We hope that the algorithm will provide ED clinicians with a rapid, automatic readout that they could use for discharge planning and the prevention of PTSD." She envisions the algorithm being implemented in the future as a feature of electronic medical records.

The researchers also plan to test their algorithm at predicting PTSD in people whose traumatic experiences come in the form of health events such as heart attacks and strokes, as opposed to visits to the emergency department.

Hints of the 4th dimension have been detected by physicists

What would it be like to experience the 4th dimension?

Two different experiments show hints of a 4th spatial dimension. Credit: Zilberberg Group / ETH Zürich
Technology & Innovation

Physicists have understood at least theoretically, that there may be higher dimensions, besides our normal three. The first clue came in 1905 when Einstein developed his theory of special relativity. Of course, by dimensions we’re talking about length, width, and height. Generally speaking, when we talk about a fourth dimension, it’s considered space-time. But here, physicists mean a spatial dimension beyond the normal three, not a parallel universe, as such dimensions are mistaken for in popular sci-fi shows.

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How often do vaccine trials hit paydirt?

Vaccines find more success in development than any other kind of drug, but have been relatively neglected in recent decades.

Pedro Vilela/Getty Images
Surprising Science

Vaccines are more likely to get through clinical trials than any other type of drug — but have been given relatively little pharmaceutical industry support during the last two decades, according to a new study by MIT scholars.

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