Drops That Impact A Very Hot Surface Will Surf On Their Own Vapor, And Ones That Hit A Very Cold Surface

Lunar Eclipse 2019

Image Credit: Zachary Wells

Tools of the Trade: How Parker Solar Probe Will Study the Sun

Our Parker Solar Probe will get closer to the Sun than any spacecraft has ever gone – it will fly right through the Sun’s corona, part of the Sun’s atmosphere.

This spacecraft is full of cutting-edge technology, from its heat shield down to its guidance and control systems. It also carries four suites of advanced instruments designed to study the Sun in a multitude of ways.  

1. Measuring particles

Two of Parker Solar Probe’s instrument suites are focused on measuring particles – electrons and ions – within the corona.

One of these particle-measuring instrument suites is SWEAP (Solar Wind Electrons Alphas and Protons). SWEAP counts the most common particles in the solar wind – the Sun’s constant outflow of material – and measures their properties, like velocity, density and temperature. Gathering this information about solar wind particles will help scientists better understand why the solar wind reaches supersonic speeds and exactly which part of the Sun the particles come from.

One instrument in the SWEAP suite is the Solar Probe Cup. Most of the instruments on Parker Solar Probe stay safe and cool in the shadow of the heat shield, but the Solar Probe Cup is one of the few that sticks out. That’s so it can capture and measure particles streaming straight out from the Sun, and it had to go through some intense testing to get ready for this position in the Sun’s incredibly hot corona.  

Credit: Levi Hutmacher/Michigan Engineering

The ISʘIS suite (pronounced EE-sis, and including the symbol for the Sun in its acronym) also measures particles. ISʘIS is short for Integrated Science Investigation of the Sun, and this instrument suite measures particles that move faster – and therefore have more energy – than the solar wind.

These measurements will help scientists understand these particles’ lifecycles – where they came from, how they got to be traveling so fast (these particles can reach speeds more than half the speed of light!) and what path they take as they travel away from the Sun and into interplanetary space.

2. Taking pictures – but not of the Sun’s surface.

WISPR (Wide-Field Imager for Parker Solar Probe) has the only two cameras on Parker Solar Probe – but they’re not pointed directly at the Sun. Instead, WISPR looks out the side of the spacecraft, in the direction it’s traveling, looking at the space Parker Solar Probe is about to fly through. From that vantage point, WISPR captures images of structures within the corona like coronal mass ejections, or CMEs. CMEs are clouds of solar material that occasionally explode from the Sun at millions of miles per hour. Because this solar material is magnetized, CMEs can trigger geomagnetic storms when they reach Earth – which, in turn, can cause effects like auroras and even, in extreme cases, power outages.  

Right now, our observations of events like these come from satellites orbiting near Earth, so WISPR will give us a whole new perspective. And, scientists will be able to combine WISPR’s images with Parker Solar Probe’s direct particle measurements to get a better idea of how these structures change as they travel.

3. Studying electric & magnetic fields

The FIELDS instrument suite is appropriately named: It’s what scientists will use to study the electric and magnetic fields in the corona.

Electric and magnetic fields are key to understanding what happens, not only on the Sun, but throughout space, because they are the primary driver accelerating charged particles. In particular, a process called magnetic reconnection – when magnetic field lines explosively realign, sending particles rocketing away at incredible speeds – is thought to drive solar explosions, as well as space weather effects on Earth, like the aurora.

FIELDS measures electric and magnetic field at high time resolution, meaning it takes lots of measurements in a short amount of time, to track these processes and shed some light on the mechanics underlying the Sun’s behavior. FIELDS’ measurements are precisely synced up with those of the SWEAP suite (one of the sets of instruments studying particles) so that scientists can match up the immediate effects that electric and magnetic fields have on the material of the solar wind.

Parker Solar Probe launches summer 2018 on its mission to study the Sun. Keep up with the latest on the mission at nasa.gov/solarprobe or follow us on Twitter and Facebook.

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“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ (I’ve found it!), but ‘That’s funny…’”

— Isaac Asimov | Author - I, Robot | Professor - Biochemistry

Arp 188 and the Tadpole’s Tail

Coal Sack & Carina Nebulae - Stirling Ranges, Western Australia

The faint rings of Uranus, shot in 1986, are made of countless fragments of water ice containing radiation-altered organic material.

Credit: NASA/JPL/Michael Benson, Kinetikon Pictures

What is a protostar?

The formation of stars begins with the collapse and fragmentation of molecular clouds into very dense clumps.  These clumps initially contain ~0.01 solar masses of material, but increase in mass as surrounding material is accumulated through accretion.  The temperature of the material also increases while the area over which it is spread decreases as gravitational contraction continues, forming a more stellar-like object in the process.  During this time, and up until hydrogen burning begins and it joins the main sequence, the object is known as a protostar.

This stage of stellar evolution may last for between 100,000 and 10 million years depending on the size of the star being formed. If the final result is a protostar with more than 0.08 solar masses, it will go on to begin hydrogen burning and will join the main sequence as a normal star.  For protostars with masses less than this, temperatures are not sufficient for hydrogen burning to begin and they become brown dwarf stars.

Protostars are enshrouded in gas and dust and are not detectable at visible wavelengths.  To study this very early stage of stellar evolution, astronomers must use infrared or microwave wavelengths.

Protostars are also known as Young Stellar Objects (YSOs).

The First Real Photo Of Entire Earth From Apollo 8 In 1968.