Saturn

NASA’s James Webb Space Telescope took its first near-infrared look at Saturn on June 25. The planet appears dark at this wavelength, as methane gas in its atmosphere absorbs sunlight — but its icy rings stay bright!

Of course Saturn brought its ring light 🪐

WHY IS THE SPACE BLACK??

Blog#306

Saturday, June 17th, 2023

Welcome back,

Look up at the night sky with your own eyes, or marvel at images of the universe online, and you'll see the same thing: the inky, abysmal blackness of space, punctuated by bright stars, planets or spacecraft. But why is it black? Why isn't space colorful, like the blue daytime sky on Earth?

Surprisingly, the answer has little to do with a lack of light.

"You would think that since there are billions of stars in our galaxy, billions of galaxies in the universe and other objects, such as planets, that reflect light, that when we look up at the sky at night, it would be extremely bright," Tenley Hutchinson-Smith, a graduate student of astronomy and astrophysics at the University of California, Santa Cruz (UCSC), told Live Science in an email. "But instead, it's actually really dark."

Hutchinson-Smith said this contradiction, known in physics and astronomy circles as Olbers' paradox, can be explained by the theory of space-time expansion — the idea that "because our universe is expanding faster than the speed of light … the light from distant galaxies might be stretching and turning into infrared waves, microwaves and radio waves, which are not detectable by our human eyes."

And because they are undetectable, they appear dark (black) to the naked eye.

That said, a 2021 study in The Astrophysical Journal suggests that space may not be as black as scientists originally thought. Through NASA's New Horizons mission to Pluto and the Kuiper Belt, researchers have been able to see space without light interference from Earth or the sun.

The team sifted through images taken by the spacecraft and subtracted all light from known stars, the Milky Way and possible galaxies, as well as any light that might have leaked in from camera quirks. The background light of the universe, they found, was still twice as bright as predicted.

The reasons for the additional brightness, which remain unknown, will be the focus of future studies. Until then, one thing seems likely: Space could very well be more "charcoal" than pitch-black.

Originally published on big livescience.com

COMING UP!!

(Wednesday, June 21st, 2023)

"WHY IS DARK MATTER SO IMPORTANT??"

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waspluto

1 year ago

Anytime i see a bunch of pride flags i have to restrain myself from saying "where mexico" bc i doubt anyone will know I'm referencing this

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8 months ago

A Tour of Cosmic Temperatures

We often think of space as “cold,” but its temperature can vary enormously depending on where you visit. If the difference between summer and winter on Earth feels extreme, imagine the range of temperatures between the coldest and hottest places in the universe — it’s trillions of degrees! So let’s take a tour of cosmic temperatures … from the coldest spots to the hottest temperatures yet achieved.

First, a little vocabulary: Astronomers use the Kelvin temperature scale, which is represented by the symbol K. Going up by 1 K is the same as going up 1°C, but the scale begins at 0 K, or -273°C, which is also called absolute zero. This is the temperature where the atoms in stuff stop moving. We’ll measure our temperatures in this tour in kelvins, but also convert them to make them more familiar!

We’ll start on the chilly end of the scale with our CAL (Cold Atom Lab) on the International Space Station, which can chill atoms to within one ten billionth of a degree above 0 K, just a fraction above absolute zero.

Cartoon of JAXA’s XRISM telescope gently rocking and back and forth on a dark blue background. The spacecraft has a roughly cylindrical body, which is depicted in light blue with various hardware shown as gray lines and shapes. Solar array "wings" extend on either side and a smaller, rounded cylindrical section pointing toward the right has small tubes extending from the end. Text above reads “XRISM’s Resolve sensor,” and text below says “0.05 K, -459.58°F (-273.10°C).”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Just slightly warmer is the Resolve sensor inside XRISM, pronounced “crism,” short for the X-ray Imaging and Spectroscopy Mission. This is an international collaboration led by JAXA (Japan Aerospace Exploration Agency) with NASA and ESA (European Space Agency). Resolve operates at one twentieth of a degree above 0 K. Why? To measure the heat from individual X-rays striking its 36 pixels!

Cartoon of the Boomerang Nebula subtly shifting on a dark blue background. The nebula is depicted as layered blobs in different shades of pink. A small light pink oval is near the center, and the entire nebula is speckled with small white dots. Text above reads “Boomerang Nebula,” and text below says “1 K, -457.9°F (-272.2°C).”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Resolve and CAL are both colder than the Boomerang Nebula, the coldest known region in the cosmos at just 1 K! This cloud of dust and gas left over from a Sun-like star is about 5,000 light-years from Earth. Scientists are studying why it’s colder than the natural background temperature of deep space.

Cartoon of Neptune against a dark blue background. The planet is mostly a medium shade of blue with streaks of lighter and darker blues. Text above reads “Neptune,” and text below says “72 K, -330°F (-201°C).”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Let’s talk about some temperatures closer to home. Icy gas giant Neptune is the coldest major planet. It has an average temperature of 72 K at the height in its atmosphere where the pressure is equivalent to sea level on Earth. Explore how that compares to other objects in our solar system!

Cartoon of Death Valley in an oval inside a dark blue background. A yellow sun slowly sets in a golden sky behind abstract dark brown mountains. Text at the top of the scene reads “Death Valley,” and text below says “330 K, 134°F (56.7°C).”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

How about Earth? According to NOAA, Death Valley set the world’s surface air temperature record on July 10, 1913. This record of 330 K has yet to be broken — but recent heat waves have come close. (If you’re curious about the coldest temperature measured on Earth, that’d be 183.95 K (-128.6°F or -89.2°C) at Vostok Station, Antarctica, on July 21, 1983.)

We monitor Earth's global average temperature to understand how our planet is changing due to human activities. Last year, 2023, was the warmest year on our record, which stretches back to 1880.

Cartoon of Earth against a deep purple background. The surface of Earth shows royal blue water and the green shapes of landforms. A triangular wedge has been removed from the side facing us, revealing the layers inside. The innermost layer is a blazing white, followed by yellow, orange, and red as they near the surface. Text above reads “Earth’s core,” and text below says “5,600 K, 10,000°F (5,300°C).”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

The inside of our planet is even hotter. Earth’s inner core is a solid sphere made of iron and nickel that’s about 759 miles (1,221 kilometers) in radius. It reaches temperatures up to 5,600 K.

Cartoon of Rigel and the constellation Orion against a deep purple background. On the right is a glowing light blue star with a slightly mottled surface that slowly spins. To its left is a pattern of dots connected with lines, showing the shape of Orion, which very loosely resembles a human with a bow. Rigel’s location is marked in the lower right of the constellation and connected to the larger star with a translucent triangle. Text above reads “Surface of Rigel,” and text below says “11,000 K, 20,000°F.”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We might assume stars would be much hotter than our planet, but the surface of Rigel is only about twice the temperature of Earth’s core at 11,000 K. Rigel is a young, blue star in the constellation Orion, and one of the brightest stars in our night sky.

Cartoon of a cloud of ionized hydrogen against a purple background. Concentric magenta blobs fill the center of the image, getting lighter toward the center. A bright white point is slightly right of center, surrounded by a yellow-orange haze and X-shaped spikes of light. Text above reads “Hydrogen ionizes,” and text below says “158,000 K, 284,000°F.”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We study temperatures on large and small scales. The electrons in hydrogen, the most abundant element in the universe, can be stripped away from their atoms in a process called ionization at a temperature around 158,000 K. When these electrons join back up with ionized atoms, light is produced. Ionization is what makes some clouds of gas and dust, like the Orion Nebula, glow.

Cartoon of the Sun and its corona against a dark purple background. The Sun is a glowing yellow circle at the center, surrounded by wispy white streaks extending outward that gently wave, representing the corona. Occasionally, smaller white filaments travel inward or outward along very subtle white lines that curve around the Sun, depicting its magnetic field. Text above reads “Solar corona,” and text below says “3 million K, 5.4 million°F.”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We already talked about the temperature on a star’s surface, but the material surrounding a star gets much, much hotter! Our Sun’s surface is about 5,800 K (10,000°F or 5,500°C), but the outermost layer of the solar atmosphere, called the corona, can reach millions of kelvins.

Our Parker Solar Probe became the first spacecraft to fly through the corona in 2021, helping us answer questions like why it is so much hotter than the Sun's surface. This is one of the mysteries of the Sun that solar scientists have been trying to figure out for years.

Cartoon of a galaxy cluster against a bright purple background. The cluster is depicted as a dozen orange and yellow ovals and abstract spiral galaxies within a cloud in shades of brown with a small tan blob at its center. Text above reads “Perseus galaxy cluster,” and text below says “50 million K, 90 million°F.”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Looking for a hotter spot? Located about 240 million light-years away, the Perseus galaxy cluster contains thousands of galaxies. It’s surrounded by a vast cloud of gas heated up to tens of millions of kelvins that glows in X-ray light. Our telescopes found a giant wave rolling through this cluster’s hot gas, likely due to a smaller cluster grazing it billions of years ago.

Cartoon of layers of material slowly expanding after a supernova explosion against a bright purple background. A bright central dot represents the exploding star, which is surrounded by concentric spiky layers in different shades of pink and purple. Text above reads “Supernova shell,” and text below says “300 million K, 550 million°F.”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Now things are really starting to heat up! When massive stars — ones with eight times the mass of our Sun or more — run out of fuel, they put on a show. On their way to becoming black holes or neutron stars, these stars will shed their outer layers in a supernova explosion. These layers can reach temperatures of 300 million K!

Cartoon of material swirling around a black hole, our view distorted by strong gravity, against a deep purple background. The center of the image is a black hole, with a thin ring of orange around it, then a small gap, and then a striped disk of material. The disk in front of the black hole appears as we would expect, with the disk arcing in front of the black hole like a flat pancake. However, the far side of the disk is visible above and below the black hole, instead of being blocked by it. This is due to the black hole’s gravity, which redirects the light on its path to us. Text above reads “Black hole corona,” and text below says “1 billion K, 1.8 billion°F.”

Credit: NASA's Goddard Space Flight Center/Jeremy Schnittman

We couldn’t explore cosmic temperatures without talking about black holes. When stuff gets too close to a black hole, it can become part of a hot, orbiting debris disk with a conical corona swirling above it. As the material churns, it heats up and emits light, making it glow. This hot environment, which can reach temperatures of a billion kelvins, helps us find and study black holes even though they don’t emit light themselves.

JAXA’s XRISM telescope, which we mentioned at the start of our tour, uses its supercool Resolve detector to explore the scorching conditions around these intriguing, extreme objects.

Cartoon of the moments of the universe after the big bang, against a pinkish-purple background. A blazing blob of white fills the center of the image, surrounded by a halo of bright pink, with spikes of magenta extending in all directions. Text above reads “Universe's first second,” and text below says “10 billion K, 18 billion°F.”

Credit: NASA's Goddard Space Flight Center/CI Lab

Our universe’s origins are even hotter. Just one second after the big bang, our tiny, baby universe consisted of an extremely hot — around 10 billion K — “soup” of light and particles. It had to cool for a few minutes before the first elements could form. The oldest light we can see, the cosmic microwave background, is from about 380,000 years after the big bang, and shows us the heat left over from these earlier moments.

Cartoon of a plasma formed within CERN’s Large Hadron Collider, against a purple background. A blue spherical cloud slowly expands at the center of the image, electric blue on the outside and a deeper blue at the center. Blue lines and dots surround this cloud, moving outward as it becomes larger. Text above reads “Large Hadron Collider,” and text below says “5.5 trillion K, 9.9 trillion°F.”

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

We’ve ventured far in distance and time … but the final spot on our temperature adventure is back on Earth! Scientists use the Large Hadron Collider at CERN to smash teensy particles together at superspeeds to simulate the conditions of the early universe. In 2012, they generated a plasma that was over 5 trillion K, setting a world record for the highest human-made temperature.

Want this tour as a poster? You can download it here in a vertical or horizontal version!

The background of this infographic is dominated by a long line, snaking from the upper right to the lower left in a giant "S." The line has temperatures marked from 0 at the bottom to 10-to-the-12 at the top. The guide is built around the Kelvin, the absolute temperature scale used by scientists. There are markings for each power of 10 at regular intervals. Each of the text elements is accompanied by a stylistic drawing. Some of the elements marked are: Large Hadron Collider, 5.5 trillion K (highest temperature measured); Universe’s first second, 10 billion K; Black hole corona, 1 billion K (plasma around accreting black holes); Solar corona, 3 million K; Earth’s core, 5,600 K; Death Valley, 330 K (Earth’s highest natural surface temperature); Neptune, 72 K (average atmospheric temperature at 1 bar level); Boomerang Nebula, 1 K (coldest-known natural environment); XRISM’s Resolve sensor operates at 0.05 K; Absolute zero, 0 K.

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

Explore the wonderful and weird cosmos with NASA Universe on X, Facebook, and Instagram. And make sure to follow us on Tumblr for your regular dose of space!

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waspluto

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