What Was It Like When Starlight First Broke Through The Universe’s Neutral Atoms?
“The light created in the earliest era of stars and galaxies all plays a role. The ultraviolet light works to ionize the matter around it, enabling visible light to progressively farther and farther as the ionization fraction increases. The visible light gets scattered in all directions until reionization has gotten far enough to enable our best telescopes today to see it. But the infrared light, also created by the stars, passes through even the neutral matter, giving our 2020s-era telescopes a chance to find them.
When starlight breaks through the sea of neutral atoms, even before reionization completes, it gives us a chance to detect the earliest objects we’ll ever have seen. When the James Webb Space Telescope launches, that will be the first thing we look for. The most distant reaches of the Universe are within our view. We just have to look and find out what’s truly out there.”
Something existing in our Universe is not quite the same as something being detectable in our Universe. We know that, at some point in our past, we created the first generation of stars, the second generation of stars, and the very first galaxies to exist in our Universe. But in order to detect them, there has to be some way for that light to travel through the Universe to our observatories and telescopes monitoring the skies today. There’s an obstacle standing in the way of that, though: the neutral atoms formed just hundreds of thousands of years after the Big Bang. When the first hints of starlight begin permeating through space, they encounter these neutral atoms, which largely thwarts them. It takes hundreds of millions of years for starlight to win.
But with enough persistence and star-formation, the light will eventually break through. Come get the cosmic story of how this all actually happens!
This Is How Hubble Will Use Its Remaining Gyroscopes To Maneuver In Space
“It might seem to be just another example of crumbling infrastructure in the United States, but you must neither underestimate Hubble nor the resourcefulness of astronomers and scientists and engineers overall. The two (or maybe three) remaining gyroscopes are of a new and upgraded design, designed to last five times as long as the original gyroscopes, which includes the one that recently failed. The James Webb Space Telescope, despite being billed as Hubble’s successor, is actually quite different, and will launch in 2021.
Even with one gyroscope, the Hubble Space Telescope should still be operational and capable of providing complementary observations to James Webb. This reduced-gyro mode has been planned for a long time. The only disappointment is that we may need to enter it so soon.”
One of the hallmarks of a successful NASA project is overengineering. Things will go wrong, break down, and degrade over time. One of the best examples is the Opportunity rover, which was designed for a 90 day mission and wound up living for nearly 15 years. But many people don’t appreciate how successfully overengineered Hubble is. Now well into its 28th year, it’s some 9 years removed from its final servicing mission. The gyroscopes that were installed included three of the old type and three of the new type, and the final old-style gyroscope has just failed.
Yet Hubble can continue operating and doing astronomy on just one gyroscope. Its demise has been greatly exaggerated; come learn the truth about Hubble today!
These Are The Most Distant Objects We’ve Ever Discovered In The Universe
“For planets of any type, the quasar RX J1131-1231, lensed by rogue planets, holds the record: 3.9 billion light-years distant. The most distant normal star is known as Icarus, 9 billion light-years away, lensed and magnified by a massive galaxy cluster. 23 billion light-years away is the most distant supernova ever seen: SN 1000+0216.”
Our quest to learn about the Universe is a quest of ever-receding horizons. From planets, moons, and other objects in our Solar System to stars, galaxies, quasars, and gamma-ray bursts, we just keep shattering records as far distance goes. Improvements in technology, technique, and increased observing time allow us to reveal things that simply couldn’t be observed previously. Yet we’re by no means done, just because we’ve set a slew of new records in the opening two decades of the 21st century. With the launch of the James Webb Space Telescope, the hope of a Planet Nine, and the advent of 30-meter-class astronomy from the ground, the records we know and adore today may all be in the rear-view mirror just a few years from now.
What are the most distant objects of all different types in the Universe? Get the 2018 update right now!
Ask Ethan: Are We Deceiving Ourselves By Searching For B-Modes From Inflation?
“I have a question about B-Modes. I’ve read Dr. Keating’s book, Losing the Nobel Prize. In the book, he details his team’s search for B-modes, and claims this would be smoking gun for inflation. Dr. Hossenfelder, in a blog post, says this isn’t true and there are other ways to produce B-modes. What is the correct view?”
Perhaps the greatest danger in science is to go out, look for a predicted effect, find it, and declare victory. Why is that such a danger? Because your idea for how the effect was generated might not be the only possibility, or even the most accurate one. If I have a wild new theory that predicts some far-distant star will have a habitable planet around it, the detection of that planet does not necessarily mean the wild new theory is correct. When it comes to the origin of the Universe, our leading theory is cosmic inflation, which predicts a B-mode polarization signature in the cosmic microwave background. Are there other ways to generate those B-mode signatures, though? And if we find them, does that mean that inflation is correct, or might that be a premature conclusion?
This is a key problem, and a hard problem, in theoretical physics. But we can say a whole lot that’s intelligent on this topic, and still be correct. Let’s find out.
The U.S. Naval Institute (USNI) just published an essay in "Proceedings" on "low energy nuclear reactions." THe essay endorses the "Widom-Larsen Theory" of LENR. This "essay" actually won second prize in USNI's 2018 "Emerging Technologies" essay contest. Quite frankly, I can't see this "technology" emerging anytime or anywhere. Comments?
Apologies for the very late reply. I haven’t come across this essay and i’m not a nuclear physicist, but i can comment this: low energy nuclear reactions are a relevant topic. If the “proceedings” they present allow, for example, to extract a great quantity of energy from a low energy reaction, i guess that maybe this technology could be applicable in some fields. Idk, to have a relevant comment i would need understand what that technology is.
If You Traveled Far Enough Through Space, Would You Return To Your Starting Point?
“Finally, could it be the case, just as the Earth has two dimensions we can move in on it (north-south and east-west, but not up-and-down), that the Universe might be a higher-dimensional structure like a hypersphere or a hypertorus where the various dimensions are closed and finite, curving back on themselves?
If that were the case, if you could travel in a straight line for long enough, you would wind up right back where you started. If you didn’t age, perhaps you could even wind up seeing the back of your own head just by looking for long enough, as your eyes would eventually encounter the light emitted from your own origin. If the Universe were like this, how would we figure it out?”
One of the things people curious about the Universe wonder, if they stare up at the sky for long enough and start pondering the possibilities, is whether it repeats itself on large enough scales. The Universe might loop back on itself, meaning that if you traveled in a straight line for far enough, you might eventually return to your starting point. If the Universe were like this, is there any way we could know? Would there be any unambiguous, observable signature? And if we didn’t see it, could we rule the possibility out, or would it linger as being plausible, but just out of reach of our cosmic horizons?
It’s a fascinating possibility, and one that the best science we have today has something, but not everything, to say about. Come get our best answers today!
These 5 Women Deserved, And Were Unjustly Denied, A Nobel Prize In Physics
“The fact of the matter is that there is no concrete evidence that women are in any way inherently inferior to men when it comes to work in any of the sciences or any of their sub-fields. But there is overwhelming evidence for misogyny, sexism, and institutional bias that hinders their careers and fails to recognize them for their outstanding achievements. When you think of the Nobel Laureates in Physics and wonder why there are so few women, make sure you remember Cecilia Payne, Chien-Shiung Wu, Vera Rubin, Jocelyn Bell-Burnell, and Lise Meitner. The Nobel committee may have forgotten or overlooked their contributions until it was too late, but that doesn’t mean we have to. In all the sciences, we want the best, brightest, most capable, and hardest workers this world has to offer. Looking back on history with accurate eyes only serves to demonstrate how valuable, and yet undervalued, women in science have been.”
In most intellectual lines of work, if you claimed that a certain type of person wasn’t mentally capable of doing as good a job as another, you’d be rightfully called a bigot. Yet somehow, in a myriad of the sciences (such as physics), there are those who simultaneously claim that “women are inferior to men” alongside the claim that it isn’t sexist or bigoted to say so.
But what there is a long history of, in physics, is women being denied their due credit for discoveries and advances that they were an integral part of. Even in the aftermath of last week’s events, when physicist Donna Strickland became just the third woman ever to be awarded a Nobel Prize, many have claimed that she isn’t worthy, for reasons that have never been applied to men.
Well, meet five women you might not be aware of who certainly earned a Nobel Prize, even if they were never awarded one. We cannot rewrite history, but we can right the legacy of its wrongs in our public consciousness.
What Was It Like When The Universe Made The Very First Galaxies?
“The first galaxies required a large number of steps to happen first: they needed stars and star clusters to form, and they needed for gravity to bring these star clusters together into larger clumps. But once you make them, they are now the largest structures, and can continue to grow, attracting not only star clusters and gas, but additional small galaxies. The cosmic web has taken its first major step up, and will continue to grow further, and more complex, over the hundreds of millions and billions of years to follow.”
For millions upon millions of years, there were no stars in the Universe. As the first one finally formed, the star clusters that birthed them became the largest structures in the Universe. Yet these were too small and limited to be considered galaxies. For that, we need more than one massive star cluster in the same place. We need for them to merge, triggering a starburst and creating a larger, more luminous object. It takes much longer for that to happen than to merely form stars, and the Universe was a very different place by then. The Big Bang may have started everything off uniformly and without anything more than the seeds of structure, but gravity, and time, are awfully powerful tools.
Come learn what the Universe was like when we made the very first galaxies. It’s a story you won’t soon forget!
The Universe Has A Speed Limit, And It Isn’t The Speed Of Light
“We believe that every charged particle in the cosmos — every cosmic ray, every proton, every atomic nucleus — should limited by this speed. Not just the speed of light, but a little bit lower, thanks to the leftover glow from the Big Bang and the particles in the intergalactic medium. If we see anything that’s at a higher energy, then it either means:
1. particles at high energies might be playing by different rules than the ones we presently think they do,
2. they are being produced much closer than we think they are: within our own Local Group or Milky Way, rather than these distant, extragalactic black holes,
3. or they’re not protons at all, but composite nuclei.”
If you were to try and travel as close to the speed of light as possible, you’d never get there because of Einstein’s relativity and the fact that you have mass. But even if you pumped an arbitrary amount of energy into you, you still wouldn’t get arbitrarily close to the speed of light. Instead, you’d find that there was a barrier or cutoff just a little bit below the speed of light: about 80 femtometers-per-second below the ultimate cosmic speed limit. That’s because the leftover glow from the Big Bang, the cosmic microwave background, exists no matter where you go, and prevents you from going any faster. Even if you beat that speed, it will knock you back down below it in short order.
There’s a speed limit for matter in the Universe, and it isn’t the speed of light. Come find out the details of why today!
For The Last Time: The LHC Will Not Make An Earth-Swallowing Black Hole
“To prevent decay, new, unknown physics — for which no evidence exists — must be invoked.
Even if the newly created black hole were stable, it could not devour the Earth. The maximum rate it could consume matter is 1.1 × 10-25 grams-per-second.
It would take 3 trillion years to grow to a mass of 1 kg.”
Well, it was only a matter of time before someone trotted out the long-debunked claim that the LHC could possibly create an Earth-destroying black hole. I, like most of you, just didn’t expect that person to be the esteemed astronomer Sir Martin Rees!
Well, you’ll be happy to know that not only is his claim untrue, but it’s very easy to demonstrate why. You don’t have to point to cosmic rays (which are more energetic and have struck Earth for billions of years) or rely on anything we haven’t already directly observed. In fact, we can even imagine exotic scenarios that could result in the creation of a black hole, and even then, the Earth is entirely safe.
In less than 200 words, you, too, can learn why the LHC will not make an Earth-swallowing black hole. Sorry, all you armchair supervillains out there.