What Was It Like When The Universe Made Its Heaviest Elements?
“For a long time, it was speculated that merging neutron stars would provide the origin of these elements, as two massive balls of neutrons smashing together could create an endless variety of heavy atomic nuclei. Sure, most of the mass from these objects would merge together into a final-stage object like a black hole, but a few percent should be ejected as part of the collision.
In 2017, observations made with both telescopes and with gravitational wave observatories confirmed that not only are neutron star mergers responsible for the overwhelming majority of these heavy elements, but that short-period gamma ray bursts can be linked to these mergers as well. Now known as a kilonova, it’s well-understood that neutron star-neutron star mergers are the origin of the majority of the heaviest elements found throughout the Universe.”
For those of you keeping track, this is the 22nd article I’ve written in my “what was it like when…” series. There’s an entire past and future history of our Universe to tell, and we haven’t even reached the present day.
Enjoy the story of how we made the heaviest elements of all, and stay tuned for even more.
Here’s How To See Uranus And Mars Meet In The Sky This Week
“Although there are eight major planets in the Solar System, most of us never see Uranus or Neptune. Undiscovered until well after the invention of the telescope, both worlds cannot be reliably spotted with the naked eye. On rare occasion, however, one of those worlds will pass close to an easily-visible astronomical landmark, providing a perfect viewing opportunity. This Tuesday night, Uranus will pass within just 1° of Mars, enabling clear views with technology no more complex than binoculars.”
Although we know of the existence of many astronomical objects in our Solar System, most of us have never seen any planets other than the ones visible to our naked eye for ourselves. The easiest way to change that is to take advantage of astronomical conjunctions when they occur. When two planets pass close by one another in the sky, they can both clearly be seen at the same time through the right astronomical tool, like a pair of binoculars. This February 12/13, Mars and Uranus will meet in the night sky, passing within 1 degree of each other.
Here’s how to see Uranus, with extra tips for how to discern the planet your seeking from mere nearby, normal stars!
Ask Ethan: What Will Our First Direct Image Of An Earth-Like Exoplanet Look Like?
“[W]hat kind of resolution can we expect? [A] few pixels only or some features visible?”
I’ve got good news and bad news. With the next generation of space-based and ground-based telescopes on the way, we’ll finally be able to image Earth-sized and super-Earth-sized planets around the nearest stars to us directly. Unfortunately, even the largest of these telescopes won’t be able to resolve these planets beyond being a single pixel (with light leaking into the adjacent pixels) in angular size. But even with that limitation, we should be able to recover signatures of continents, oceans, icecaps, clouds, atmospheric contents, water, and potentially even life.
Come find out what we will (and won’t) be able to do with our first direct images of Earth-sized exoplanets, coming to you in just a few years!
Galaxy Clusters Are Where Galaxies Like The Milky Way Go To Die
“When a galaxy enters a rich, massive cluster, it has to contend with two murderous factors. A single major merger can use up all the gas in both progenitor galaxies, leading to a red-and-dead elliptical galaxy. Even without one, the intracluster medium is rich in matter, and speeding through it can strip out a galaxy’s gas. Without that gaseous presence, new stars can no longer form.”
Here in our Local Group, our Milky Way forms stars at a low but steady rate, and will likely continue to do so for billions of years. It’s only our impending major merger with Andromeda that will use up all of our gas, and turn us into a giant elliptical without the capacity to form new stars. If we were more isolated, we could continue to form stars for trillions of years: many times the age of the Universe.
But if we were in a rich galaxy clusters, our demise would be not only certain, but much more rapid. Here’s the proof.
Sorry, Astronomers Haven’t Found The Brightest Quasar In The Entire Universe
“This new quasar is fascinating, but not for the reasons you might have heard. It’s not the brightest object near our cosmic dawn, but one of the faintest such objects discovered. It’s only because of the power of gravitational lensing, a chance alignment of an intervening galaxy, and the unique rules of Einstein’s relativity that we were able to find it at all.
We may have found the quasar with the largest apparent brightness in the early Universe, which is remarkable in and of itself. But our goal is to understand the Universe as it is, not as it appears to us. When we take that into account, this quasar is exactly in line with what we expect it to be. And that’s a fascinating story in and of itself, with no additional sensationalism necessary.”
Imagine looking out at the distant Universe and finding what looks like a quasar with the brightness of 600 trillion Suns. That’s more than twice as bright as the brightest known quasar, out of hundreds, at comparable distances. It implies a black hole that’s as massive as 10 billion Suns, in a galaxy forming stars at tens of thousands of times the rate of the Milky Way, less than a billion years after the Big Bang.
Sound impossible? That’s because it is impossible. Despite what might have been reported by many, that’s not what’s happening at all. Get the real story here!
A Billion Years In Interstellar Space: What We Know Today About ‘Oumuamua
“The incredible conclusion isn’t just that ‘Oumuamua came from outside
of our Solar System, but that this was both rare and common. For an
individual object, like ‘Oumuamua, it will likely never come this close
to another Solar System again. Only once every 100 trillion years — some
10,000 times the current age of the Universe — will it pass so close to
a star. As scientist Gregory Laughlin put it, “this was the time of
But for our Solar System, because of the sheer
number of objects like this flying through the galaxy, we probably
experience a close encounter like this around a few times per year. 2017
marked the first time we saw such an object, but we’ve likely gotten
billions of them over the course of our Solar System’s lifetime. Some of
them, if nature was kind, may have even collided with Earth.
There may be as many as ~1025
of objects like this flying through our galaxy, and every so often,
we’ll get lucky enough to encounter one of them. For the first time,
we’ve actually seen one of them for ourselves.”
In 2017, our Solar System received a visit like never before: from an object originating from interstellar space. Likely ejected more than a billion years ago from a foreign solar system, it happened to pass within even the orbit of Mercury, only becoming visible to our telescopes when it came within 60 lunar distances of the Earth.
But we found it, observed it, and learned everything we could about it. What do we know, today? Spoiler: it’s not from aliens.