Category: astronomy

This Is How Eta Carinae Survived A Near-Supernova Eruption

“In all of astronomy, no stellar event releases more energy than a supernova. Humanity hasn’t witnessed a naked-eye supernova within our galaxy since 1604, but Eta Carinae came close. In 1843, it brightened to become the second brightest star in the sky, gradually fading away by 1857. Almost as much energy was released as in standard supernovae, but Eta Carinae remained intact.”

Over the past 400 years, the brightest object to appear in humanity’s night sky wasn’t a supernova, but rather a supernova impostor. These events are extremely rare compared to supernovae, yet we happened to get lucky enough to discover one just 7,500 light-years away. When we look at it today, we see the remnants of a large ejection, where 10-20 solar masses of material were expelled from a star that still totals more than 100 solar masses. For a long time, it was an absolute mystery how this could have occurred, but 2005-era observations revealed a binary companion with unusual properties, leading to a fascinating suggestion: perhaps a third star was devoured, causing the outburst and the subsequent ejection of matter.

As crazy as it sounds, we get to watch the event on a cosmic instant replay, and could wind up confirming or refuting this wild but plausible idea.

Ask Ethan: Do Ancient Galaxies Get Magnified By The Expanding Universe?

“Do ancient galaxies appear larger to us than they really were, due to the expansion of the Universe? If so, then by how much?”

It seems like the simplest, most straightforward idea in the world: the farther away an object is, the smaller it appears. View the same object when it’s twice as far away, and it will only appear to be half as large in terms of angular size. Place it ten times as far away, and you’ll see it appear just one-tenth the size. 

But this is only true in flat, static space. In the expanding Universe, this relationship falls apart, particularly when you factor in dark energy. More distant objects appear smaller the farther away you look, but only to a point. Galaxies that are about 14-to-15 billion light-years away will appear the smallest, and then the same-sized galaxy will actually appear larger the farther away you look! This may be counterintuitive, but there’s real, solid science to back it up. 

Come learn how the expanding Universe really does magnify the most distant galaxies of all, and what the fascinating implications are for the next generation of ultra-powerful telescopes!

These Are The Top 10 Hubble Images Of 2019

1.) Galaxy pair AM 2026-424. With two massive galaxies colliding head-on, an intermediate ring of blue stars appears before the inevitable final merger.”

In 1990, the Hubble Space Telescope was launched, providing humanity with unprecedented views of the Universe. Each and every year, with 2019 marking the 30th consecutive year, a series of images get produced that shed light on some aspect of our Universe in unprecedented fashion. Despite Hubble’s big gyroscope failure (and scare) at the end of last year, 2019 has turned out to be no exception, with 10 spectacular new images and 7 almost-as-spectacular honorable mentions.

There’s a great chance you missed most of these during the year, but now’s your opportunity to get the year’s Hubble highlights all in one place!

Ask Ethan: Was The Critical Evidence For The Big Bang Discovered By Accident?

“The cosmic microwave background is a landmark evidence of the Big Bang origin of the universe. How come this discovery is labelled as an accidental one?”

Imagine that you lived in a world where nobody knew where the Universe came from. Sure, different theories led to a myriad of possibilities, but it takes observations to decide what’s correct in this Universe. In the 1920s, Georges Lemaitre worked out the first early details of the Universe originating from a hot, dense state. In the 1940s, George Gamow and his collaborators started to pull out robust predictions, like the nuclear predictions for fusion in the early Universe, the growth of stars, galaxies and clusters in the Universe, and the existence and rudimentary properties of a leftover glow: today’s Cosmic Microwave Background. Yet the actual discovery of this leftover radiation from the Big Bang, despite the meticulous planning of a group working to detect it explicitly, truly was a serendipitous accident. 

You’ll never look at the expression “one astronomer’s noise is another astronomer’s data” the same way again!

Your 2019 Holiday Gift Guide For Space, Astronomy, And Science Lovers

At The Edge Of Time, by Dan Hooper. This new book, out just a few weeks ago, is my favorite new science book of 2019. As a theoretical cosmologist, Dan is all the things I appreciate in a scientist who writes about his own research: he’s knowledgeable, comprehensive, and careful to get the details right. He has clear opinions and preferences, but is willing and able to push them aside in service of teaching the reader about the strengths and weaknesses of a variety of perspectives on a myriad of issues at the frontiers of physics.

If you’re mystified and curious about the mysteries of the Universe, including dark matter, dark energy, and cosmic inflation, and want a unique take on all of these puzzles with a peek behind how science-in-action works, you won’t want to miss this book. (I liked it so much that Dan is going to be my next upcoming guest on the Starts With A Bang podcast!)”

Do you love space, science, astronomy, physics, the Moon, and learning about the frontiers of what we know? Well, the holidays are coming up (today is Black Friday), and if that describes you or someone close to you in your life, here is a complete gift guide for the science enthusiast in your life.

With a total of 11 recommended books, a wall calendar, hats, accessories, and even a unique puzzle, you won’t want to miss this holiday gift guide!

Spectacular Planetary And Lunar Alignment To Grace The Post-Sunset Thanksgiving Skies

“As 2019 has progressed, Saturn has followed Jupiter in its sky-crossing migration from east to west. Meanwhile, for about the past month, Venus has emerged as an evening star after sunset, drifting from west to east. On Sunday, November 24, Venus and Jupiter nearly met — achieving a conjunction — coming within 1.4° of each other.”

Normally, astronomical conjunctions are a big and spectacular deal, especially when they’re close, and particularly when they’re between the two brightest planets of all: Venus and Jupiter. But on American Thanksgiving, November 28, an extraordinary and unusual event will occur: the young crescent Moon will align with Venus and Jupiter as well, fresh off a conjunction. While skywatchers worldwide will get a spectacular show, the best views come for people in European and African longitudes, as they’ll see the Moon appear between closely spaced Venus and Jupiter.

This rare sight will only last for that one night, so make sure you know where to look and what to look for, because it’s your last chance to experience it for years!

This Is Why ‘Multi-Messenger Astronomy’ Is The Future Of Astrophysics

“The three types of signals we know how to collect from the Universe — light, particles, and gravitational waves — all deliver fundamentally different types of information right to our front door. By combining the most precise observations we can take with each of these, we can learn more about our cosmic history than any one of these signal types, or “messengers,” can provide in isolation.

We’ve already learned how neutrinos are produced in supernova, and how their travel path is less impeded by matter than light’s is. We’ve already linked merging neutron stars with kilonovae and the production of the heaviest elements in the Universe. With multi-messenger astronomy still in its infancy, we can expect a deluge of new events and new discoveries as this science progresses throughout the 21st century.

Just as you can learn more about a tiger by hearing its growl, smelling its scent, and watching it hunt than you can from a still image alone, you can learn more about the Universe by detecting these fundamentally different types of messengers all at once. Our bodies might be limited in terms of the senses we can use in any given scenario, but our knowledge of the Universe is limited only by the fundamental physics governing it. In the quest to learn it all, we owe it to humanity to use every resource we can muster.”

In 2017, three different gravitational wave observatories from across the world, LIGO Livingston, LIGO Hanford, and the Virgo detector all witnessed the arrival of gravitational waves from a neutron star collision some 130,000,000 light-years away. Two seconds after the wave signal ceased, the first light from the merger arrived. A new term that was previously reserved for professional astronomers, “multi-messenger astronomy,” suddenly entered the public arena.

But what is multi-messenger astronomy? What makes something a “messenger” and why is it important? As it turns out, it’s going to revolutionize how we understand our Universe in the 21st century. Come find out how today.

Starts With A Bang #50: The Hunt For Planet Nine And Beyond

What lies out there, in the outer Solar System, beyond the orbit of the last known planet? Up until 1992, you would have said Pluto and its moon (maybe “moons” if you were willing to speculate), but even the existence of the Kuiper belt was doubted by many. Of course, all of that changed with the discovery of many different objects, including the more-massive-than-Pluto world discovered in 2003: Eris. We quickly realized that Pluto was not unique, but one member of a distinct class of objects thoroughly different than the planets. In 2006, we created the “dwarf planet” classification for non-planetary objects that still were Pluto-like.

But more recently, a compelling but controversial idea has emerged: the idea of a Planet Nine that is more massive than even Earth, but lies hundreds of times farther away that we are from the Sun. Both of these achievements, the theorizing of Planet Nine and the Pluto-killing discovery of Eris, come courtesy of the same planetary astronomer: Mike Brown. Dive into a fascinating conversation with him and me right here on the 50th edition of the Starts With A Bang podcast!

(Image credit: Caltech/R. Hurt (IPAC))

Ask Ethan: Did We Just Find The Universe’s Missing Black Holes?

“As interesting as this new black hole is, and it really is most likely a black hole, it cannot tell us whether there’s a mass gap, a mass dip, or a straightforward distribution of masses arising from supernova events. About 50% of all the stars ever discovered exist as part of a multi-star system, with approximately 15% in bound systems containing 3-to-6 stars. Since the multi-star systems we see often have stellar masses similar to one another, there’s nothing ruling out that this newfound black hole didn’t have its origin from a long-ago kilonova event of its own.

So the object itself? It’s almost certainly a black hole, and it very likely has a mass that puts it squarely in a range where at most one other black hole is known to exist. But is the mass gap a real gap, or just a range where our data is deficient? That will take more data, more systems, and more black holes (and neutron stars) of all masses before we can give a meaningful answer.”

Last week, an incredible new story came out: scientists discovered a massive object some 10,000 light-years away that emits no light of its own. From the giant star in orbit around it, we were able to infer its mass to a well-constrained range, with the mean value hovering right at 3.3 solar masses.The lack of X-rays from it, based on the field strength associated with neutron stars and the orbit of the giant star itself, very strongly indicates that this object is not a neutron star, but a black hole.

Does this mean we’ve discovered a black hole in the so-called “mass gap” range? Yes! But does it disprove the existence of a mass gap overall? Not so much. Come get the full story on this edition of Ask Ethan!

This One Distant, Red, Gas-Free Galaxy Defies Astronomers’ Expectations

“When two similarly-sized galaxies merge, it triggers a starburst: a massive formation of new stars. Under the right circumstances, some gas will form stars while the remainder is expelled, lost forever to the intergalactic medium. Once the gas for forming new stars is used up, the galaxy simply ages as the bluest, most massive stars die off. Over billions of years, only the redder, dimmer, lower mass stars remain.”

In astronomy, young galaxies actively form stars, and glow bright blue through the process. Only after many billions of years and at least one cataclysmic event do galaxies settle down into a gas-free, red state, once all the bluer stars have died out. “Red and dead” galaxies appear in the late Universe, normally as giant elliptical galaxies that lost their gas aeons ago.

Which is why this one galaxy is so puzzling: it’s red, dead, massive and compact, but it’s also sending us its light from 10.8 billion years ago!

How did this galaxy get so old-looking when it’s actually so young? The mystery continues, but here’s what we know so far.