Paul M. Sutter, Author at Universe Today

April 19, 2019April 19, 2019 by Paul M. Sutter

What Will the James Webb Space Telescope See? A Whole Bunch of Dust, That’s What

With its helical appearance resembling a snail’s shell, this reflection nebula seems to spiral out from a luminous central star in this new NASA/ESA Hubble Space Telescope image. The star in the centre, known as V1331 Cyg and located in the dark cloud LDN 981 — or, more commonly, Lynds 981 — had previously been defined as a T Tauri star. A T Tauri is a young star — or Young Stellar Object — that is starting to contract to become a main sequence star similar to the Sun. What makes V1331Cyg special is the fact that we look almost exactly at one of its poles. Usually, the view of a young star is obscured by the dust from the circumstellar disc and the envelope that surround it. However, with V1331Cyg we are actually looking in the exact direction of a jet driven by the star that is clearing the dust and giving us this magnificent view. This view provides an almost undisturbed view of the star and its immediate surroundings allowing astronomers to study it in greater detail and look for features that might suggest the formation of a verylow-mass object in the outer circumstellar disc.

When it comes to the first galaxies, the James Webb Space Telescope will attempt to understand the formation of those galaxies and their link to the underlying dark matter. In case you didn’t know, most of the matter in our universe is invisible (a.k.a. “dark”), but its gravity binds everything together, including galaxies. So by studying galaxies – and especially their formation – we can get some hints as to how dark matter works. At least, that’s the hope. It turns out that astronomy is a little bit more complicated than that, and one of the major things we have to deal with when studying these distant galaxies is dust. A lot of dust.

That’s right: good old-fashioned dust. And thanks to some fancy simulations, we’re beginning to clear up the picture.

March 11, 2019March 11, 2019 by Paul M. Sutter

Massive Photons Could Explain Dark Matter, But Don’t

A computer simulation of the distribution of matter in the universe. Orange regions host galaxies; blue structures are gas and dark matter. Credit: TNG Collaboration

I’ll be the first to admit that we don’t understand dark matter. We do know for sure that something funny is going on at large scales in the universe (“large” here meaning at least as big as galaxies). In short, the numbers just aren’t adding up. For example, when we look at a galaxy and count up all the hot glowing bits like stars and gas and dust, we get a certain mass. When we use any other technique at all to measure the mass, we get a much higher number. So the natural conclusion is that not all the matter in the universe is all hot and glowy. Maybe some if it is, you know, dark.

But hold on. First we should check our math. Are we sure we’re not just getting some physics wrong?

March 4, 2019March 4, 2019 by Paul M. Sutter

Astronomers are Using NASA’s Deep Space Network to Hunt for Magnetars

An artist's impression of a magnetar, a highly magnetic, slowly rotating neutron star. Credit: ESO/L. Calçada

Right, magnetars. Perhaps one of the most ferocious beasts to inhabit the cosmos. Loud, unruly, and temperamental, they blast their host galaxies with wave after wave of electromagnetic radiation, running the gamut from soft radio waves to hard X-rays. They are rare and poorly understood.

Some of these magnetars spit out a lot of radio waves, and frequently. The perfect way to observe them would be to have a network of high-quality radio dishes across the world, all continuously observing to capture every bleep and bloop. Some sort of network of deep-space dishes.

Like NASA’s Deep Space Network.

February 22, 2019February 22, 2019 by Paul M. Sutter

Meet WFIRST, The Space Telescope with the Power of 100 Hubbles

The Wide First Infrared Telescope (so far). Image credit: NASA/TJT Photography

WFIRST ain’t your grandma’s space telescope. Despite having the same size mirror as the surprisingly reliable Hubble Space Telescope, clocking in at 2.4 meters across, this puppy will pack a punch with a gigantic 300 megapixel camera, enabling it to snap a single image with an area a hundred times greater than the Hubble.

With that fantastic camera and the addition of one of the most sensitive coronagraphs ever made – letting it block out distant starlight on a star-by-star basis – this next-generation telescope will uncover some of the deepest mysteries of the cosmos.

Oh, and also find about a million exoplanets.

February 5, 2019February 5, 2019 by Paul M. Sutter

How The Sun’s Scorching Corona Stays So Hot

We’ve got a mystery on our hands. The surface of the sun has a temperature of about 6,000 Kelvin – hot enough to make it glow bright, hot white. But the surface of the sun is not its last later, just like the surface of the Earth is not its outermost layer. The sun has a thin but extended atmosphere called the corona. And that corona has a temperature of a few million Kelvin.

How does the corona have such a higher temperature than the surface?

Like I said, a mystery.

January 31, 2019January 31, 2019 by Paul M. Sutter

Uh oh, a Recent Study Suggests that Dark Energy’s Strength is Increasing

The concept of accelerating expansion does get you wondering just how much it can accelerate. Theorists think there still might be a chance of a big crunch, a steady-as-she-goes expansion or a big rip. Or maybe just a little rip?

Staring into the Darkness

The expansion of our universe is accelerating. Every single day, the distances between galaxies grows ever greater. And what’s more, that expansion rate is getting faster and faster – that’s what it means to live in a universe with accelerated expansion. This strange phenomenon is called dark energy, and was first spotted in surveys of distant supernova explosions about twenty years ago. Since then, multiple independent lines of evidence have all come to the same morose conclusion: the universe is getting fatter and fatter faster and faster.

January 10, 2019January 10, 2019 by Paul M. Sutter

It Looks Like Dark Matter Can be Heated Up and Moved Around

Look at a galaxy, what do you see? Probably lots of stars. Nebulae too. And that’s probably it. A whole bunch of stars and gas in a variety of colorful assortments; a delight to the eye. And buried among those stars, if you looked carefully enough, you might find planets, black holes, white dwarves, asteroids, and all sorts of assorted chunky odds and ends. The usual galactic milieu.

What you wouldn’t see is what most of that galaxy is really made of. You wouldn’t see the invisible, the hidden. You wouldn’t see the bulk of that galactic mass. You wouldn’t see the dark matter.

December 31, 2018 by Paul M. Sutter

A Guide to Hunting Zombie Stars

R Aquarii is called a symbiotic star system because of their relationship. As the white dwarf draws in material from the Red Giant, it ejects some if it in weird looping patterns, seen in this Hubble image. Image Credit: By Judy Schmidt from USA - Symbiotic System R Aquarii, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=63473035

Apparently not all supernovas work. And when they fail, they leave behind a half-chewed remnant, still burning from leftover heat but otherwise lifeless: a zombie star. Astronomers aren’t sure how many of these should-be-dead creatures lurk in the interstellar depths, but with recent simulations scientists are making a list of their telltale signatures so that future surveys can potentially track them down.

Continue reading “A Guide to Hunting Zombie Stars”

December 21, 2018December 21, 2018 by Paul M. Sutter

New Research Reveals How Galaxies Stay Hot and Bothered

This visualization uses data from simulations of orbital motions of gas swirling around at about 30% of the speed of light on a circular orbit around the black hole. Credit: ESO/Gravity Consortium/L. Calçada

It’s relatively easy for galaxies to make stars. Start out with a bunch of random blobs of gas and dust. Typically those blobs will be pretty warm. To turn them into stars, you have to cool them off. By dumping all their heat in the form of radiation, they can compress. Dump more heat, compress more. Repeat for a million years or so.

Eventually pieces of the gas cloud shrink and shrink, compressing themselves into a tight little knots. If the densities inside those knots get high enough, they trigger nuclear fusion and voila: stars are born.

Continue reading “New Research Reveals How Galaxies Stay Hot and Bothered”

December 6, 2018December 6, 2018 by Paul M. Sutter

Astronomers Count all the Photons in the Universe. Spoiler Alert: 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Photons

The NASA/ESA Hubble Space Telescope offers this delightful view of the crowded stellar encampment called Messier 68, a spherical, star-filled region of space known as a globular cluster. Mutual gravitational attraction amongst a cluster’s hundreds of thousands or even millions of stars keeps stellar members in check, allowing globular clusters to hang together for many billions of years. Astronomers can measure the ages of globular clusters by looking at the light of their constituent stars. The chemical elements leave signatures in this light, and the starlight reveals that globular clusters' stars typically contain fewer heavy elements, such as carbon, oxygen and iron, than stars like the Sun. Since successive generations of stars gradually create these elements through nuclear fusion, stars having fewer of them are relics of earlier epochs in the Universe. Indeed, the stars in globular clusters rank among the oldest on record, dating back more than 10 billion years. More than 150 of these objects surround our Milky Way galaxy. On a galactic scale, globular clusters are indeed not all that big. In Messier 68's case, its constituent stars span a volume of space with a diameter of little more than a hundred light-years. The disc of the Milky Way, on the other hand, extends over some 100 000 light-years or more. Messier 68 is located about 33 000 light-years from Earth in the constellation Hydra (The Female Water Snake). French astronomer Charles Messier notched the object as the sixty-eighth entry in his famous catalogue in 1780. Hubble added Messier 68 to its own impressive list of cosmic targets in this image using the Wide Field Camera of Hubble’s Advanced Camera for Surveys. The image, which combines visible and infrared light, has a field of view of approximately 3.4 by 3.4 arcminutes. Credit: Hubble/NASA/ESA

Imagine yourself in a boat on a great ocean, the water stretching to the distant horizon, with the faintest hints of land just beyond that. It’s morning, just before dawn, and a dense fog has settled along the coast. As the chill grips you on your early watch, you catch out of the corner of your eye a lighthouse, feebly flickering through the fog.

And – yes – there! Another lighthouse, closer, its light a little stronger. As you scan the horizon more lighthouses signal the dangers of the distant coast.
Continue reading “Astronomers Count all the Photons in the Universe. Spoiler Alert: 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 Photons”