Ask Ethan: Can We Find Exoplanets With Exomoons Like Ours?
“But, by far, the best possibility we have today is through direct measurement of a transiting exomoon. If the planet that’s orbiting the star can make a viable transiting signal, then all it will take is the same serendipitous alignment to have its moon transit the star, and sufficiently good data to tease that signal out of the noise.
This is not a pipe dream, but something that has already occurred once. Based on data taken by NASA’s Kepler mission, the stellar system Kepler-1625 is of particular interest, with a transiting light curve that not only displayed the definitive evidence of a massive planet orbiting it, but of a planet that wasn’t transiting with the exact same frequency you’d expect orbit after orbit.”
If you want to find an exoplanet, the most successful methods are to look for the effect it has on the light from it’s parent star. But what about if you wanted to find an exomoon? There are some subtle effects at play, but if we think hard about what they might be, we can come up with a series of methods that could reveal an exomoon’s presence indirectly, and pinpoint exactly where and when we could look to try and detect one directly. Thought to be a great technique for the upcoming James Webb Space Telescope to take advantage of TESS data, we’ve actually succeeded once already, using the Hubble/Kepler combo!
You may have missed it, but we think we’ve found the first exomoon as of late last year. What does the future hold for exomoons? Find out on this week’s Ask Ethan!
This Is How We Will Discover The Most Distant Galaxy Ever
“Sometime in the distant past, likely when the Universe was less than 2% its current age, the very first galaxy of all formed when massive star clusters merged together, resulting in an unprecedented burst of star formation. The high-energy light from these stars struggles to escape, but the longer-wavelength light can penetrate farther through neutral atoms. The expansion of the Universe redshifts all the light, stretching it far beyond anything Hubble could potentially observe, but next-generation infrared telescopes should be able to catch it. And if we observe the right part of the sky, with the right instruments, for a sufficiently long time to reveal the right details about these objects, we’ll push back the cosmic frontier of the first galaxies even farther.
Somewhere, the most distant, first galaxy of all is out there, waiting to be discovered. As the 2020s approach, we can feel confident that we’ll not only shatter the current cosmic record-holder, but we know exactly how we’ll do it.”
13.8 billion years ago, our Universe as-we-know-it began with the hot Big Bang. There were no stars or galaxies back then; there weren’t even bound structures of any type. Everything was too energetic, and would immediately be destroyed by the unfathomably high temperatures and energies that every particle possessed. Yet, with time, the Universe expanded and cooled. Protons, nuclei, and neutral atoms formed; overdense regions gravitationally pulled-in mass and matter; stars were born, lived, died, and new stars were born in their aftermath. At some point, the first large star clusters merged together, passing a critical threshold and forming the first galaxy in the Universe.
That’s what we want to find. We’ve gone back to when the Universe was just 3% its present age, but that’s not enough. We must go father. We must find the first one. Here’s how we’ll do it.
Happy Halloween from Starts With A Bang!
In a first, I have gone full-astrophysics for Halloween this year.
In all its golden glory, I have put together a James Webb Space Telescope costume this year, complete with sunshield and all!
Happy Halloween, Tumblr!
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!
First Stars Formed No Later Than 250 Million Years After The Big Bang, With Direct Proof
“We see MACS1149-JD1 as it was 530 million years after the Big Bang, while inside, it has a special signature: oxygen. Oxygen is only produced by previous generations of stars, indicating that this galaxy is already old.
MACS1149-JD1 was imaged with microwave (ALMA), infrared (Spitzer), and optical (Hubble) data combined.
The results indicate that stars existed nearly 300 million years before our observations.”
One of the great quests of astronomers today is to measure and locate the very first stars in the Universe. As far back as Hubble can see, to when the Universe was just 3-5% its current age, the Universe is still full of galaxies, even though they’re smaller and bluer than the ones we have today. But within these galaxies, we can also find evidence that the stars in there aren’t the very first ones; they contain evidence for prior generations of stars in their spectral signatures. From the second-most distant galaxy ever discovered, itself just 530 million years after the Big Bang, we see evolved stars. They indicate that the very first ones formed no later than 250 million years after the Big Bang.
The James Webb Space Telescope will be able to see that far! In less than 3 years, we’ll peer beyond where we’ve ever seen before. And there will no doubt be something breathtaking to look at.
When Will We Break The Record For Most Distant Galaxy Ever Discovered?
“Finally, beyond a certain distance, the Universe hasn’t formed enough stars to reionize space and make it 100% transparent.
We only perceive galaxies in a few serendipitous directions, where copious star-formation occurred.
In 2016, we fortuitously discovered GN-z11 at a redshift of 11.1: from 13.4 billion years ago.
But recent, indirect evidence suggests stars formed at even greater redshifts and earlier times.“
It was only a couple of years ago that we set the current record for where the most distant galaxy is: from 13.4 billion years ago, when the Universe was just 3% its current age. This record is unlikely to be broken with our current set of observatories, as discovering a galaxy this distant required a whole bunch of unlikely, serendipitous phenomena to line up at once. But in 2020, the James Webb Space Telescope will launch: an observatory optimized for finding exactly the kinds of galaxy that push past the limits of what Hubble can do. We fully expect to not only break the record for most distant galaxy ever discovered, but to learn, for the first time, exactly where and when the first galaxies in the Universe truly formed.
Until then, it’s lots of fun to speculate as to when and where they might be, but it will take the observations of a lifetime to smash this cosmic record!
How The James Webb Space Telescope Will Deploy (In An Ideal World)
“Once the launch vehicle reaches a distance of 10,000 kilometers from Earth, just a half hour into its journey, the telescope separates from the upper stage of the rocket. At this point, JWST is free from the launch vehicle, and is now on its own, on its way to its ultimate destination. Two minutes later, the first key, but difficult step must succeed: to deploy its solar array. James Webb has a battery on board, but will only need it until the array is deployed. The thrusters will then fire, pointing the solar panels towards the Sun and orienting the observatory properly for the next step. If the array fails, the battery will last only a few hours. This step, like a great many, is a single-point-of-failure for the entire mission.”
The James Webb Space Telescope is optimized for uncovering so many secrets of the Universe, it’s impossible to list them all in a single article. From the first stars and galaxies to atmospheres around Earth-sized worlds, from the molecules present in newly-forming planets to direct images of Jupiter-sized worlds in distant solar systems, and from the pristine material left over from the Big Bang to finding the majority of water in the Universe, James Webb will answer questions that no observatory has ever addressed before. But only if it successfully launches and deploys! This takes a tremendous amount of work from vastly separate teams, all coming together without a single failure. Yet the plans have been vetted and tested as thoroughly as possible from the ground, and once the final preparatory steps are taken later this year, all that remains will be to execute the plan.
What has to happen in order for James Webb to successfully launch, deploy, and get onto the science? Find out, in-depth, today!
When Did The First Stars Appear In The Universe?
“But there’s more science to be done. Even with James Webb, we likely won’t get all the way to the very first star of all, but we’re very likely to gain a much better handle on exactly where they are and when they are. And as for the first pristine stars? The first stars verified to have nothing other than hydrogen and helium in them? If nature is kind to us, James Webb won’t only bring us the very first one of those, but will bring us many examples.
The Universe is out there, waiting for us to discover it. If we want to know the answer, all we need to do is look. As we build better observatories and take better data, our understanding of all that’s out there will only improve.”
If we look out as far as we can, there’s a big gap between what we know and what must be there. The most distant galaxy we’ve ever found is GN-z11, whose light comes from when the Universe was only 400 million years old. The next picture we have is the cosmic microwave background, emitted from when the Universe was a mere 380,000 years old. At that point, there were no stars; by time we get to 400 million years of age, we have quite large and bright galaxies. So when did the first stars actually, truly appear? It’s a question that we know an awful lot about what the answer must look like, but we’re still a few steps away from actually finding them.
Come find out all we know, and check out a video that Paul Matt Sutter and I made together explaining what we know… and what comes next!
5 Surprising Facts About The First Galaxies In The Universe
“1.) There are no rocky planets present among the very first stars and galaxies. Whenever you form stars from a molecular cloud of gas, you can fully expect that gas to fragment into a whole slew of clumps, which grow at different rates depending on how large they are to begin with and what else is in their vicinity. Large gas clouds will grow stars and planets of many different sizes, but even the smallest worlds that first form will be made exclusively of gas: hydrogen and helium. Without any previous generations of stars, there are no heavier elements to form solid bodies like rocky planets or moons. Small balls of gas may form, but when those stars ignite, they’ll simply be burned off into interstellar space by the ionizing radiation of those first nuclear fires in the Universe.”
Looking farther and farther into the distant Universe is the equivalent of looking farther and farther back in time. Although Hubble has shown us galaxies from when the Universe is just 400 million years old, and satellites to measure the Cosmic Microwave Background can show us a snapshot at 380,000 years, we have no information about what’s in between. That means, to date, we have yet to see the Universe’s first stars and galaxies! While James Webb will shed a new cosmic light on that era, allowing us to view these galaxies for the first time, there are some pieces of information that we already know. These galaxies must be tiny compared to the ones we have today; they will never be seen by Hubble, even with an infinite amount of observing time; they should already contain the seeds of supermassive black holes from their inception; and they very likely contain the most massive stars found in the entire Universe.
Come find out five surprising facts about the very first galaxies in the Universe, and learn what James Webb will allow us to finally know for certain!