Sights and Sounds of the Solar System

Seven Minutes at Venus

On its ever-tightening orbits round the Sun, NASA’s Parker Solar Probe swings by Venus for rerouting functions. But one doesn’t merely cross by our sister planet with out taking some knowledge.

Parker’s third flyby on July 11, 2020, took it simply 833 kilometers (517 miles) above the planet’s floor. While the spacecraft was effectively above the thick ambiance, it went shut sufficient to cross by way of Venus’s ionosphere, the sparse layer of charged particles surrounding the planet.

Parker’s FIELDS instrument, which measures electrical and magnetic fields, detected a low, plasma-wave-induced hum from the ionosphere throughout closest strategy that lasted seven minutes:

The knowledge verify that now that the Sun is at the minimal of its 11-year exercise cycle, Venus’s ionosphere is way thinner than it was when the Pioneer Venus Orbiter final measured it immediately, in 1992, again when the Sun’s exercise was peaking. The change is anticipated, since Venus doesn’t boast a planetary magnetic subject and responds on to solar exercise, however quantifying the change will assist astronomers achieve a greater understanding of Venus’s ambiance and its gradual escape to space.

Read extra in NASA’s press release and in Geophysical Research Letters.

See Jupiter in Another Light

The king of planets provides a examine in contrasts in a trio of pictures that spotlight excessive climate on Jupiter. Hotspots glow vibrant at infrared wavelengths however seem brown in seen gentle, whereas the best storm that exhibits up red at seen gentle turns into darkish at different wavelengths. Explore the pictures beneath with a watch for some key options.  

Labeled Jupiter
Labels added to this visible-light Hubble Space Telescope picture of Jupiter level out a number of atmospheric options on the planet, together with a “brown barge,” 4 scorching spots (which seem vibrant in the infrared picture from Gemini North), a superstorm, the Great Red Spot, and Red Spot Jr. (often known as Oval BA).
NASA/ESA/NOIRLab/NSF/AURA/M.H. Wong and I. de Pater (UC Berkeley) et al.

Jupiter’s Great Red Spot stands out for its darkness at ultraviolet wavelengths. That’s as a result of the similar molecules that give the anticyclone its distinctive red coloration soak up blue and ultraviolet gentle. In the infrared picture, although, the storm’s thick, swirling clouds block radiation from the planet in order that the Great Red Spot almost disappears from the picture altogether. Red Spot Jr., often known as Oval BA, follows the similar wavelength-dependent sample.

Before Image After Image

The counterrotating layers of clouds, on the different hand, stay distinguished in any respect wavelengths. However, the stripes fade close to the darkened poles in the ultraviolet picture, as haze in the stratosphere absorbs rising quantities of ultraviolet photons.

Before Image After Image

The seen and ultraviolet views had been captured by the Wide Field Camera 3 on the Hubble Space Telescope, whereas the infrared picture comes from the Near-Infrared Imager (NIRI) on the Gemini North telescope in Hawaiʻi. The pictures proven right here, taken on January 11, 2017, had been half of an extended marketing campaign to trace climate patterns on the planet.

Read extra in NASA’s press release and in the Astrophysical Journal Supplement Series.

Voyager 1 Hears Interstellar “Hum”

Voyager 1 sailed out of the solar system in 2012 when it crossed the heliopause, the boundary that separates the magnetic bubble surrounding our Sun from interstellar space. Now in the space between stars, it’s nonetheless sending again indicators detected by its Plasma Wave Subsystem instrument. The indicators include occasional “whistles,” attributable to sudden will increase in density, many of them attributable to eruptions from our personal Sun. But tucked amongst the louder indicators is a faint, low-frequency hum that’s coming from the sparse materials unfold out throughout the near-vacuum of space.

Stella Koch Ocker (Cornell University) and colleagues used the sign they discovered to check the density of interstellar materials. The sign has continued from 2017 onwards, as Voyager 1 has crossed 10 instances the distance between Earth and the Sun. The crew finds the density is altering over time (and space) in a way that traces turbulence touring by way of the plasma that’s unfold out between the stars.

Sadly, there’s no audio translation of this sign simply but, however you’ll be able to see the low-frequency hum in the determine beneath. If the skinny, persistent line extending from 2017 onward had been translated into sound, it will be almost a single tone as a result of its vary of frequency is so slim.

Weak however almost steady plasma waves – seen as a skinny red line on this graphic – join stronger occasions in Voyager 1’s Plasma Wave Subsystem knowledge.
NASA / JPL-Caltech / Stella Ocker

Read extra in NASA’s wonderful press release and in Nature Astronomy.


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