We use a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!
If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!
If you would like to sign up for the AstronomyCast Solar Eclipse Escape, where you can meet Fraser and Pamela, plus WSH Crew and other fans, visit our site linked above and sign up!
We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.
We usually record Astronomy Cast as a live Google+ Hangout on Air every Friday at 1:30 pm Pacific / 4:30 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.
The speed of light gives us an amazing tool for studying the Universe. Because light only travels a mere 300,000 kilometers per second, when we see distant objects, we’re looking back in time.
You’re not seeing the Sun as it is today, you’re seeing an 8 minute old Sun. You’re seeing 642 year-old Betelgeuse. 2.5 million year-old Andromeda. In fact, you can keep doing this, looking further out, and deeper into time. Since the Universe is expanding today, it was closer in the past.
Run the Universe clock backwards, right to the beginning, and you get to a place that was hotter and denser than it is today. So dense that the entire Universe shortly after the Big Bang was just a soup of protons, neutrons and electrons, with nothing holding them together.
In fact, once it expanded and cooled down a bit, the entire Universe was merely as hot and as dense as the core of a star like our Sun. It was cool enough for ionized atoms of hydrogen to form.
Because the Universe has the conditions of the core of a star, it had the temperature and pressure to actually fuse hydrogen into helium and other heavier elements. Based on the ratio of those elements we see in the Universe today: 74% hydrogen, 25% helium and 1% miscellaneous, we know how long the Universe was in this “whole Universe is a star” condition.
It lasted about 17 minutes. From 3 minutes after the Big Bang until about 20 minutes after the Big Bang. In those few, short moments, clowns gathered all the helium they would ever need to haunt us with a lifetime of balloon animals.
The fusion process generates photons of gamma radiation. In the core of our Sun, these photons bounce from atom to atom, eventually making their way out of the core, through the Sun’s radiative zone, and eventually out into space. This process can take tens of thousands of years. But in the early Universe, there was nowhere for these primordial photons of gamma radiation to go. Everywhere was more hot, dense Universe.
The Universe was continuing to expand, and finally, just a few hundred thousand years after the Big Bang, the Universe was finally cool enough for these atoms of hydrogen and helium to attract free electrons, turning them into neutral atoms.
This was the moment of first light in the Universe, between 240,000 and 300,000 years after the Big Bang, known as the Era of Recombination. The first time that photons could rest for a second, attached as electrons to atoms. It was at this point that the Universe went from being totally opaque, to transparent.
And this is the earliest possible light that astronomers can see. Go ahead, say it with me: the Cosmic Microwave Background Radiation. Because the Universe has been expanding over the 13.8 billion years from then until now, the those earliest photons were stretched out, or red-shifted, from ultraviolet and visible light into the microwave end of the spectrum.
If you could see the Universe with microwave eyes, you’d see that first blast of radiation in all directions. The Universe celebrating its existence.
After that first blast of light, everything was dark, there were no stars or galaxies, just enormous amounts of these primordial elements. At the beginning of these dark ages, the temperature of the entire Universe was about 4000 kelvin. Compare that with the 2.7 kelvin we see today. By the end of the dark ages, 150 million years later, the temperature was a more reasonable 60 kelvin.
For the next 850 million years or so, these elements came together into monster stars of pure hydrogen and helium. Without heavier elements, they were free to form stars with dozens or even hundreds of times the mass of our own Sun. These are the Population III stars, or the first stars, and we don’t have telescopes powerful enough to see them yet. Astronomers indirectly estimate that those first stars formed about 560 million years after the Big Bang.
Then, those first stars exploded as supernovae, more massive stars formed and they detonated as well. It’s seriously difficult to imagine what that time must have looked like, with stars going off like fireworks. But we know it was so common and so violent that it lit up the whole Universe in an era called reionization. Most of the Universe was hot plasma.
The early Universe was hot and awful, and there weren’t a lot of the heavier elements that life as we know it depends on. Just think about it. You can’t get oxygen without fusion in a star, even multiple generations. Our own Solar System is the result of several generations of supernovae that exploded, seeding our region with heavier and heavier elements.
As I mentioned earlier in the article, the Universe cooled from 4000 kelvin down to 60 kelvin. About 10 million years after the Big Bang, the temperature of the Universe was 100 C, the boiling point of water. And then 7 million years later, it was down to 0 C, the freezing point of water.
This has led astronomers to theorize that for about 7 million years, liquid water was present across the Universe… everywhere. And wherever we find liquid water on Earth, we find life.
So it’s possible, possible that primitive life could have formed with the Universe was just 10 million years old. The physicist Avi Loeb calls this the habitable Epoch of the Universe. No evidence, but it’s a pretty cool idea to think about.
I always find it absolutely mind bending to think that all around us in every direction is the first light from the Universe. It’s taken 13.8 billion years to reach us, and although we need microwave eyes to actually see it, it’s there, everywhere.
Did you hear that Dark Energy doesn’t exist any more? Neither does Dark Matter? It turns out that NASA recalculated the Zodiac and now you’re an Ophiuchan! Science is hard enough, but communicating that science out to the public when there are publications hungry for traffic is even harder! Here’s how to parse the click-bait science titles.
We usually record Astronomy Cast as a live Google+ Hangout on Air every Friday at 1:30 pm Pacific / 4:30 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.
Special Guest:
Dr. Matt Golombek, Senior Research Scientist at the JPL; Mars Exploration Rover Project Scientist; Mars Exploration Program Landing Site Scientist.
We use a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!
If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!
If you would like to sign up for the AstronomyCast Solar Eclipse Escape, where you can meet Fraser and Pamela, plus WSH Crew and other fans, visit our site linked above and sign up!
We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.
The wonderful thing about science is that it’s constantly searching for new evidence, revising estimates, throwing out theories, and sometimes discovering aspects of the Universe that we never realized existed.
The best science is skeptical of itself, always examining its own theories to find out where they could be wrong, and seriously considering new ideas to see if they better explain the observations and data.
What this means is that whenever I state some conclusion that science has reached, you can’t come back a few years later and throw that answer in my face. Science changes, it’s not my fault.
I get it, VY Canis Majoris isn’t the biggest star any more, it’s whatever the biggest star is right now. UY Scuti? That what it is today, but I’m sure it’ll be a totally different star when you watch this in a few years.
What I’m saying is, the science changes, numbers update, and we don’t need to get concerned when it happens. Change is a good thing. And so, it’s with no big surprise that I need to update the estimate for the number of galaxies in the observable Universe. Until a couple of weeks ago, the established count for galaxies was about 200 billion galaxies.
But a new paper published in the Astrophysics Journal revised the estimate for the number of galaxies, by a factor of 10, from 200 billion to 2 trillion. 200 billion, I could wrap my head around, I say billion all the time. But 2 trillion? That’s just an incomprehensible number.
Does that throw all the previous estimates for the number of stars up as well? Actually, it doesn’t.
The observable Universe measures 13.8 billion light-years in all directions. What this means is that at the very edge of what we can see, is the light left that region 13.8 billion years ago. Furthermore, the expansion of the Universe has carried to those regions 46 billion light-years away.
Does that make sense? The light you’re seeing is 13.8 billion light-years old, but now it’s 46 billion light-years away. What this means is that the expansion of space has stretched out the light from all the photons trying to reach us.
What might have been visible or ultraviolet radiation in the past, has shifted into infrared, and even microwaves at the very edge of the observable Universe.
Since astronomers know the volume of the observable Universe, and they can calculate the density of the Universe, they know the mass of the entire Universe. 3.4 x 10^54 kilograms including regular matter and dark matter. They also know the ratio of regular matter to dark matter, so they can calculate the total amount of regular mass in the Universe.
In the past, astronomers divided that total mass by the number of galaxies they could see in the original Hubble data and determined there were about 200 billion galaxies.
Now, astronomers used a new technique to estimate the galaxies and it’s pretty cool. Astronomers used the Hubble Space Telescope to peer into a seemingly empty part of the sky and identified all the galaxies in it. This is the Hubble Ultra Deep Field, and it’s one of the most amazing pictures Hubble has ever captured.
Astronomers painstakingly converted this image of galaxies into a 3-dimensional map of galaxy size and locations. Then, they used their knowledge of galaxy structure closer to home to provide a more accurate estimate of what the galaxies must look like, out there, at the very edge of our observational ability.
For example, the Milky Way is surrounded by about 50 satellite dwarf galaxies, each of which has a fraction of the mass of the Milky Way.
By recognizing which were the larger main galaxies, they could calculate the distribution of smaller, dimmer dwarf galaxies that weren’t visible in the Hubble images.
In other words, if the distant Universe is similar to the nearby Universe, and this is one of the principles of modern astronomy, then the distant galaxies have the same structure as nearby galaxies.
It doesn’t mean that the Universe is bigger than we thought, or that there are more stars, it just means that the Universe contains more galaxies, which have less stars in them. There are the big main galaxies, and then a smooth distribution curve of smaller and smaller galaxies down to the tiny dwarf galaxies. The total number of stars comes out to be the same number.
The galaxies we can see are just the tip of the galactic iceberg. For every galaxy we can see, there are another 9, smaller fainter galaxies that we can’t see.
Of course, we’re just a few years away from being able to see these dimmer galaxies. When NASA’s James Webb Space Telescope launches in October, 2018, it’s going to be carrying a telescope mirror with 25 square meters of collecting surface, compared to Hubble’s 4.5 square meters.
Furthermore, James Webb is an infrared telescope, a specialized tool for looking at cooler objects, and galaxies which are billions of light-years away. The kinds of galaxies that Hubble can only hint at, James Webb will be able to see directly.
So, why don’t we see galaxies in all directions with our eyeballs? This is actually an old conundrum, proposed by Wilhelm Olbers in the 1700, appropriately named Olber’s Paradox. We did a whole article on it, but the basic idea is that if you look in any direction, you’ll eventually hit a star. It could be close, like the Sun, or very far away, but whatever the case, it should be stars in all directions. Which means that the entire night sky should be as bright as the surface of a star. Clearly it isn’t, but why isn’t it?
In fact, with 10 times the number of galaxies, you could restate the paradox and say that in every direction, you should be looking at a galaxy, but that’s not what you see.
Except you are. Everywhere you look, in all directions, you’re seeing galaxies. It’s just that those galaxies are red-shifted from the visible spectrum into the infrared spectrum, so your eyeballs can’t perceive them. But they’re there.
When you see the sky in microwaves, it does indeed glow in all directions. That’s the Cosmic Microwave Background Radiation, shining behind all those galaxies.
It turns out the Universe has 10 times more galaxies than previously estimated – 2 trillion galaxies. Not 10 times the stars or mass, those numbers have stayed the same.
And, once James Webb launches, those numbers will be fine-tuned again to be even more precise. 1.5 trillion? 3.4 trillion? Stay tuned for the better number.
Special Guest:
Dr. Derrick Pitts, Chief Astronomer and Director of the Fels Planetarium at The Franklin Institute. He has been a NASA Solar System Ambassador since 2009 and serves as the Astrobiology Ambassador for the NASA/MIRS/UNCF Special Program Corporation’s Astrobiology Partnership Program. Additionally, Derrick was recently appointed to the outreach advisory board for the Thirty-Meter-Telescope at Mauna Kea in Hawaii.
We use a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!
If you would like to join the Weekly Space Hangout Crew, visit their site here and sign up. They’re a great team who can help you join our online discussions!
If you would like to sign up for the AstronomyCast Solar Eclipse Escape, where you can meet Fraser and Pamela, plus WSH Crew and other fans, visit our site linked above and sign up!
We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.
Last week, ESA’s Schiaparelli lander smashed onto the surface of Mars. Apparently its descent thrusters shut off early, and instead of gently landing on the surface, it hit hard, going 300 km/h, creating a 15-meter crater on the surface of Mars.
Fortunately, the orbiter part of ExoMars mission made it safely to Mars, and will now start gathering data about the presence of methane in the Martian atmosphere. If everything goes well, this might give us compelling evidence there’s active life on Mars, right now.
It’s a shame that the lander portion of the mission crashed on the surface of Mars, but it’s certainly not surprising. In fact, so many spacecraft have gone to the galactic graveyard trying to reach Mars that normally rational scientists turn downright superstitious about the place. They call it the Mars Curse, or the Great Galactic Ghoul.
Mars eats spacecraft for breakfast. It’s not picky. It’ll eat orbiters, landers, even gentle and harmless flybys. Sometimes it kills them before they’ve even left Earth orbit.
At the time I’m writing this article in late October, 2016, Earthlings have sent a total of 55 robotic missions to Mars. Did you realize we’ve tried to hurl that much computing metal towards the Red Planet? 11 flybys, 23 orbiters, 15 landers and 6 rovers.
How’s our average? Terrible. Of all these spacecraft, only 53% have arrived safe and sound at Mars, to carry out their scientific mission. Half of all missions have failed.
Let me give you a bunch of examples.
In the early 1960s, the Soviets tried to capture the space exploration high ground to send missions to Mars. They started with the Mars 1M probes. They tried launching two of them in 1960, but neither even made it to space. Another in 1962 was destroyed too.
They got close with Mars 1 in 1962, but it failed before it reached the planet, and Mars 2MV didn’t even leave the Earth’s orbit.
Five failures, one after the other, that must have been heartbreaking. Then the Americans took a crack at it with Mariner 3, but it didn’t get into the right trajectory to reach Mars.
Finally, in 1964 the first attempt to reach Mars was successful with Mariner 4. We got a handful of blurry images from a brief flyby.
For the next decade, both the Soviets and Americans threw all kinds of hapless robots on a collision course with Mars, both orbiters and landers. There were a few successes, like Mariner 6 and 7, and Mariner 9 which went into orbit for the first time in 1971. But mostly, it was failure. The Soviets suffered 10 missions that either partially or fully failed. There were a couple of orbiters that made it safely to the Red Planet, but their lander payloads were destroyed. That sounds familiar.
Now, don’t feel too bad about the Soviets. While they were struggling to get to Mars, they were having wild success with their Venera program, orbiting and eventually landing on the surface of Venus. They even sent a few pictures back.
Finally, the Americans saw their greatest success in Mars exploration: the Viking Missions. Viking 1 and Viking 2 both consisted of an orbiter/lander combination, and both spacecraft were a complete success.
Was the Mars Curse over? Not even a little bit. During the 1990s, the Russians lost a mission, the Japanese lost a mission, and the Americans lost 3, including the Mars Observer, Mars Climate Orbiter and the Mars Polar Lander.
There were some great successes, though, like the Mars Global Surveyor and the Mars Pathfinder. You know, the one with the Sojourner Rover that’s going to save Mark Watney?
The 2000s have been good. Every single American mission has been successful, including Spirit and Opportunity, Curiosity, the Mars Reconnaissance Orbiter, and others.
But the Mars Curse just won’t leave the Europeans alone. It consumed the Russian Fobos-Grunt mission, the Beagle 2 Lander, and now, poor Schiaparelli. Of the 20 missions to Mars sent by European countries, only 4 have had partial successes, with their orbiters surviving, while their landers or rovers were smashed.
Is there something to this curse? Is there a Galactic Ghoul at Mars waiting to consume any spacecraft that dare to venture in its direction?
Flying to Mars is tricky business, and it starts with just getting off Earth. The escape velocity you need to get into low-Earth orbit is about 7.8 km/s. But if you want to go straight to Mars, you need to be going 11.3 km/s. Which means you might want a bigger rocket, more fuel, going faster, with more stages. It’s a more complicated and dangerous affair.
Your spacecraft needs to spend many months in interplanetary space, exposed to the solar winds and cosmic radiation.
Arriving at Mars is harder too. The atmosphere is very thin for aerobraking. If you’re looking to go into orbit, you need to get the trajectory exactly right or crash onto the planet or skip off and out into deep space.
And if you’re actually trying to land on Mars, it’s incredibly difficult. The atmosphere isn’t thin enough to use heatshields and parachutes like you can on Earth. And it’s too thick to let you just land with retro-rockets like they did on the Moon.
Landers need a combination of retro-rockets, parachutes, aerobraking and even airbags to make the landing. If any one of these systems fails, the spacecraft is destroyed, just like Schiaparelli.
If I was in charge of planning a human mission to Mars, I would never forget that half of all spacecraft ever sent to the Red Planet failed. The Galactic Ghoul has never tasted human flesh before. Let’s put off that first meal for as long as we can.
I hate to tell you this, but that meat computer in your skull is constantly betraying you. Don’t worry, we’ve all got the same, but fortunately, scientists have learned how this happens, and can help us make sure our science, and lives don’t suffer because of it.
We usually record Astronomy Cast as a live Google+ Hangout on Air every Friday at 1:30 pm Pacific / 4:30 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.
If you’ve watched any Ren and Stimpy cartoons, you know that one of the greatest hazards of spaceflight is “space madness”. Only exposure to the isolation and all pervasive radiation of deep space could drive an animated chihuahua into such a state of lunacy.
What will happen if they press the history eraser button? Maybe something good? Maybe something bad? I guess, we’ll never know.
Of course, Ren and Stimpy weren’t the first fictionalized account of people losing their marbles when they fly into the inky darkness of space. There were the Reavers from Firefly, that crazy Russian cosmonaut in Armageddon, almost everyone in the movie Sunshine, and it was the problem in every second episode of Star Trek.
According to movies and television, if you’ve got space madness, you and your crewmates are in for a rough ride. If you’re lucky, you merely hallucinate those familiar space sirens, begging you to take off your space helmet and join them for eternity on that asteroid over there.
But you’re just as likely to go homicidal, turning on your crewmates, killing them one by one as a dark sacrifice to the black hole that powers your ship’s stardrive. And whatever you do, don’t stare too long at that pulsar, with its hypnotic, rhythmic pulse. The isolation, the alien psycho-waves, dark whisperings from eldritch gods speak to you though the paper-thin membrane of sanity. If we go to space, does only madness await us?
If you’ve spent any time around human beings, you know that we’ve got our share of mental disease right here on Earth. You don’t have to travel to space to suffer depression, anxiety, and other mental disorders.
Once we’re in orbit, or prancing about on the surface, of Mars, we’re going to experience our share of human physical and mental frailties. We’re going to take our basic humanity to space, including our brains.
According to the National Institute of Mental Health, 18% of the US population, or 40 million Americans suffer from some variety of anxiety-related disorder. 6.7% of adults had a major, crippling depressive episode over the course of a year.
Unless we improve treatment outcomes for mental disorders here on Earth, we can expect to see similar outcomes in space. Especially once we make exploration a little safer, and we’re not concerned with our immediate exposure to the vacuum of space. But will going to space make things worse?
NASA has carried out two studies on astronaut psychological health studies. One for the cosmonauts and astronauts on the Mir space station, and a second study for the folks on the International Space Station. They tested both the folks in space as well as their ground support staff once a week, to see how they were doing.
Although they reported some tension, there was no loss in mood or group cohesion during the mission. The crews had better cohesion when they had an effective leader on board.
Isolation working in close quarters has been heavily studied here on Earth, with submarine crews and isolated groups at research bases in Antarctica.
Earlier this year, a crew of simulated Mars astronauts emerged, unharmed from a year-long isolation experiment in Hawaii. The six international crewmembers were part of the Hawaii Space Exploration Analog and Simulation experiment, to see what would happen to potential Mars explorers, stuff on the surface of the red planet for a year.
They couldn’t leave their 110 square-meter (1,200 square-foot) habitat without a spacesuit on. What did they report? Mostly boredom. Some interpersonal issues. Now that they’re out, some are good friends, and others probably won’t stay in contact, or pay too much attention to them in their Facebook feed.
The bottom line is that it doesn’t seem like there’s too much of a risk from the isolation and close quarters. Well, nothing that we’re not used to dealing with as human beings.
But there is another problem that has revealed itself, and might be much more severe: space dementia. And we’re not talking about the song from Muse.
According to researchers from the University of California, Irvine, long term exposure to the radiation of deep space will cause significant damage to our fragile human brains. Or at least, that’s what happened to a group of rats bathed in radiation at the NASA Space Radiation Laboratory at New York’s Brookhaven National Laboratory.
Over time, the damage to their brains would cause astronauts to experience a type of dementia that causes anxiety. Brain cancer patients who receive radiation treatment are prone to this as well.
During the months and years of a Mars mission, astronauts would take a large dose of radiation, even with shielding, and the effects would be harmful to their bodies and to their brains. In fact, even when the astronauts return to Earth, their condition might worsen, with more anxiety, depression, memory problems, and a loss of decision making ability. This is a serious problem that needs to be solved if humans are going to live for a long time outside the Earth’s protective magnetosphere.
It turns out, science fiction space madness isn’t a real thing, it’s a plot device like warp drives, teleporters, and light sabers.
Isolation and close proximity isn’t much of a problem, we’ve dealt with it before, and we can still work with people, even though we hate them and the way they slurp their coffee, and lean back on their chair, even though that thing is totally going to break and they’re going to hurt themselves. And they won’t stop doing it, no matter how many times we ask them to stop.
Once again, radiation in space is a big problem. It’s out there, it’s everywhere, and we don’t have a great way to protect against it. Especially when it wrecks our brains.