NASA’s newly launched SphereX mission is up & operational and has completed its initial checkout and “first light”. Everything looks good! And now it’s starting its science operations. And that’s good enough for Pamela! And THAT means we can talk about it. So let’s do that! There’s a new space telescope in town (or at least in LEO). Let’s check out what it’s looking at and looking to do.
Show Notes
- SPHEREx Mission Status & Goal
- SPHEREx Mission Overview
- SPHEREx Observation
- LSST Observation & Scientific Goals: The collected data will enable a wide range of scientific investigations, including studying the history of the universe.
- Research Team’s Expertise & Goal
- Inflationary Pattern Analysis
- CMB Polarization and Gravitational Waves
- SPHEREx Mission and Reionization
- SPHEREx’s Role in Studying Early Universe
- SPHEREx’s Study of Water in the Galaxy
- Euclid Mission Objectives
- Importance of Ices in Formation
- Impact of Dust on Observations
- Complementary Approach to Exoplanet Study
- Unraveling Dark Matter and Dark Energy
- Upcoming Observatories
- Advocating for Space Science
- Expired Missions
Transcript
Fraser Cain: Welcome to AstronomyCast, our weekly facts-based journey through the cosmos, where we help you understand not only what we know, but how we know what we know. I’m Fraser Cain, I’m the publisher of Universe Today. me as always is Dr. Pamela Gay, Senior Scientist for the Planetary Science Institute and the Director of CosmoQuest. Hey Pamela, how are you doing?
Dr. Pamela Gay: I am doing well. I’m irrationally mad at T. coronaborealis for not granting us a NOVA.
Like, last summer it told us.
Fraser Cain: We are overdue.
Dr. Pamela Gay: Yeah, we are overdue. And of all the things in this Universe to be upset about, I have absolutely the least control over this recurrent NOVA recurring. And yet it is the thing.
Every time I look at our schedule for the rest of the year, I see that episode on things we are anticipating this summer. And my brain is like, the Universe lied to us.
Fraser Cain: Yeah, yeah, yeah. But how could you not have expected this? I mean, just think about comets, like just comets in general, meteor storms.
The Universe knows that it can do this stuff. And yet on our watch, it denies us.
Dr. Pamela Gay: I still, like stars are supposed to come on schedule. It’s what they’re supposed to do.
Fraser Cain: Yeah.
Dr. Pamela Gay: This one just refuses.
Fraser Cain: Yeah, yeah. I mean, it’s funny because like, there’s like a lot of copium. There’s a tremendous amount of copium going on as astronomers are like, you know, that we can explain that.
That was like, there was like some weird outbursts. So we thought it might arrive a little early, but it didn’t end up. But now for sure, for real, for real, we’re seeing all of the warning signs that now it’s imminent.
And I’m like, that sounds like copium. So I mean, hilariously, if it didn’t show up, it would actually be scientifically fascinating. It’s true.
That might even be more interesting than if it did show up roughly on schedule. But, you know, as they say, no, they are like wizards.
Dr. Pamela Gay: Wait, no, I haven’t heard that. Tell me how, what?
Fraser Cain: That’s hilarious. That fan wrote the exact same thing that I said in the comments, just as I said it. That’s so great.
Oh, you know, from the Hobbit, wizards are neither early nor late. They always arrive precisely when they intend to. And no, they do the same thing.
They arrive precisely when they intend to. All right. NASA’s newly launched SPHEREx mission is up and operational and has completed its initial checkout and first light.
Everything looks good. And now it’s starting its science operations. And that’s good enough for Pamela.
And that means we can talk about it. So let’s do that. And we will talk about it in a second, but it’s time for a break.
And we’re back. All right. So SPHEREx has crossed the line, the minimum viable line for Pamela’s interest and willingness to talk about a mission has gone from the purely hypothetical to the actually launched, completed first light and is now in its official science operations.
We’ve seen pictures. We’ve heard the health. Now I’m excited that we can actually talk about this mission.
But before we do, let’s talk about the history of the mission. What, what is a SPHEREx?
Dr. Pamela Gay: Oh, man. So, so SPHEREx is, is one of the most annoying acronyms because I’m utterly unable to remember all the letters. It is the spectrophotometer for the history of the universe.
So it’s a very forced acronym.
Fraser Cain: But you missed the epoch of reionization in Isis Explorer.
Dr. Pamela Gay: Yeah, that’s true. I stopped way too early.
Fraser Cain: Yeah. Spectrophotometer for the history of the universe, epoch of reionization in Isis Explorer, SPHEREx.
Dr. Pamela Gay: Yes. So this is a mission that has been in the planning since about 2012 was when the research team was like, okay, we’re going to need something that does this suite of things. Let’s start designing it, people.
It finally got funded to become an actual space telescope in 2019 and launched a few months ago. And like Gaia, it’s a mission that has a really weird design that allows it to do some super cool science.
Fraser Cain: Yeah. With Gaia, I guess one of the most amazing things with Gaia is that this, the satellite was slowly turning at the rate that it was able to process data across its CCDs. And so it was letting in the light and moving and turning at exactly the perfect rate that it was getting sort of mapping across these stars.
And it’s very interesting to see a mission that does this, that incorporates its movement as part of the science process. And of course, Gaia is one of the missions that we’re most excited about, saddest to see go and yet most enthusiastic about its upcoming data release. So how did SPHEREx, I guess, do something similar and like, what’s its goal?
Dr. Pamela Gay: So SPHEREx is doing what some people would call narrowband photometry and some people would call broadband spectroscopy, where it is looking at every object in the sky at least four times in the next two years in 102 different wavelengths in the weirdest way possible, in my personal opinion.
Fraser Cain: Okay. So let’s talk about the wavelength thing for a second here. So in a traditional telescope, like James Webb or the Hubble Space Telescope, you’ve got these filter wheels that are built in.
And so you, when you’re planning time on Hubble, you say, I need the 21 centimeter line. I need the, this line. I need the, that line.
Dr. Pamela Gay: Or not looking at 21 centimeters.
Fraser Cain: No, no, no. Sorry. Yeah, yeah.
Well, it depends on the redshift, but no, no. Yeah. So you’re looking at, you want hydrogen alpha, you want Lyman alpha, you want, you want sulfur, you want oxygen, you want these different wavelengths that are put out by these different things.
And then the Hubble will look at that object for a while and then it’ll turn to the next one and so on. But yeah, spherics is bonkers.
Dr. Pamela Gay: Yeah. Yeah. So it, it has a, a way of dispersing the light so that on it’s a little over three degree field of view, as you move along that field of view, each pixel is capturing a slightly different wavelength.
And so what it’s doing is it takes an image, everything in the image is at a slightly different wavelength. It shifts, it takes an image, everything in the image is at a slightly different wavelength. And in this manner with six different detectors that are taking on different segments of the spectrum, it is able to slowly but surely get all the wavelengths.
And it’s also in a weird orbit compared to everything else we’ve put up. It’s in a polar orbit. So it’s, it’s pretty sun synchronous.
It’s looking not at the sun very clearly. And so as it goes around and around the sky, it’s getting Boku images of the North and South polar regions. And then it’s filling in the rest of the sky as the earth goes around and around the sun.
So it’s taking image after image going around and around the solar system for two years. And, and it’s from taking a gazillion images, literally 102 times four at a minimum of each part of the sky, that it’s able to get all of these wavelengths covered.
Fraser Cain: So I’m going to try and give people like a, like a way of imagining this. So again, back to the idea of, you know, the filters that I was talking about with SphereX, imagine it just has one filter, but that filter is a rainbow. Yeah, yeah, yeah.
And so, and so then you essentially are peeping at your star through one little portion of the filter, and then you’re moving the field of view so that the star is then moving smoothly through these 102 colors in this, in this one filter. And so it saves you all that time. You don’t have to swap out your filter wheel to observe in different wavelengths.
You just slowly move the telescope so that each object that you’re trying to look at spends a little bit of time in each one of those colors and then, and, and filtering all the rest of the light out. Very efficient, very cool. And so it’s like a rainbow.
Dr. Pamela Gay: And what’s wild to me is when you look at something like Andromeda, which is going to do a pretty good job of filling that three degree field of view, every part of the galaxy is being seen in one image at a slightly different wavelength, which just completely amuses me. Yeah. It’s, it is one hairy piece of software to put together all of this data.
Fraser Cain: Yeah.
Dr. Pamela Gay: But over the course of one year, they’re able to look at order of 450 million galaxies and a whole bunch of stars.
Fraser Cain: Right.
Dr. Pamela Gay: And this is going to allow them to do a large variety of science.
Fraser Cain: All right, well, let’s talk about the science in a second, but it’s time for another break and we’re back. All right. So now you’re producing this insane amount of data.
You are observing every chunk of the sky four times over the course of the next two years, two years in each one of those in 102 different filters. What does that get you?
Dr. Pamela Gay: And to be clear, it’s not 102 different filters. It is effectively 102 different wavelengths. It’s really kind of squirrely.
Fraser Cain: Yeah. 102 different wavelengths from this giant rainbow filter.
Dr. Pamela Gay: Yeah, exactly. Um, and, and so there, they have a variety of different sciences that they’re looking to do. So history of the universe, part of its name, this is the thing that people are talking about most.
So the idea is this, this is a research team that has a lot of experience looking at the cosmic microwave background. They they’ve worked on plank. They’ve worked on ground-based, balloon-based, all sorts of different missions to look at the cosmic microwave background, trying to understand what the epic of ionization triggered.
But the thing is, when we look at the cosmic microwave background, we are essentially looking at one small window in time that that moment in history, when at the distance that light has been traveling towards earth at that time, that shell of space had all of the electrons and protons gathered together, allowing the photons to fly free. Now, if we were able to jump to some other part of the universe, we’d be able to sample a different shell, but we can’t do that. So what they’re doing instead is they’re recognizing that that pattern of hot and cold in the shell of the cosmic microwave background evolved into the large scale structure we see today.
So they are trying to get as close to the same set of measurements that the CMB provides us using galaxies. So they’re looking to see what is the detailed structure of the universe in a way that complements what Roman’s going to be doing, in a way that complements what JWST is doing. So we can get this full three-dimensional model of here’s the large scale structure of the universe, here’s how it has evolved over time.
If we run that backwards, it tells us what about the epic of inflation. And they’re hoping to be able to answer questions like…
Fraser Cain: You said the epic of inflation, do you mean reionization?
Dr. Pamela Gay: No, they’re actually looking at the epic of inflation early, early, early in the universe.
Fraser Cain: Okay, but not inflation shortly after the Big Bang.
Dr. Pamela Gay: Yeah, no, no, no. That’s what they’re looking for the footprint of.
Fraser Cain: Okay.
Dr. Pamela Gay: So what they think is the pattern of structures that we see in our modern universe and that we see in the cosmic microwave background should have a Gaussian distribution in sizes if that epic of inflation was a singular epic, if it was multiple waves of inflation. So if you can imagine a bubble went off here, a bubble went off there, a bubble went off there, and they’re all overlapping, you will end up with a non-Gaussian distribution. So what they’re trying to do is measure the statistical distribution of structures across time to get a bigger sample than we get just from the cosmic microwave background of these structures to try and get at yet more details about the epic of inflation, which we can’t see because it happened 400,000 years before we could see it.
Fraser Cain: Right. It’s obscured by the CMB.
Dr. Pamela Gay: Yeah.
Fraser Cain: Yeah. Yeah. And other people have proposed that maybe you look at the polarization of the light in the CMB to try and get some sense of the primordial gravitational waves.
Dr. Pamela Gay: And they’ve been doing that.
Fraser Cain: They’ve tried.
Dr. Pamela Gay: And it’s not there to be seen.
Fraser Cain: Yeah. Nobody’s been able to find it so far.
Dr. Pamela Gay: Yeah. So having realized that that’s not going to get them anywhere quickly, they have this as part of the science of SPHEREx, but it’s only part of it. So the other thing that they’re doing is they are looking at the epic of reionization, which is after the cosmic microwave background was formed.
So when you’re normally doing spectroscopy, you’re spreading the light out into a rainbow, you’re then moving your detector back. And the combination of the size of the slit or the size of the grading that you’re using determines how small a wavelength you’re able to sample and how much you spread out that light determines also how fine details you can see. So you can undersample, you can oversample, all sorts of things go into it.
But the key point is you’re spreading it out into a giant rainbow. And it’s really hard to get a lot of light from really faint objects. By doing what is essentially narrow band photometry, you can capture more light than you would with a normal spectrograph.
And so they’re able to start to get by fitting across 102 different pseudo filters. They’re able to get a good redshift information and they’re able to start to get at, we are seeing this spectra from galaxies at this redshift, we’re seeing this from this redshift. Ultimately, JWST is the only thing that’s going to be able to get us a detailed look at the age of reionization.
But SPHEREx at least starts to get us, here’s what we’re looking at.
Fraser Cain: Right. And we should be clear on, if we mentioned that SPHEREx is also an infrared telescope.
Dr. Pamela Gay: Yeah. Sorry. Yeah.
Fraser Cain: In the same way that Nancy Grace Roman, in the same way that Webb are. This is a really important wavelength to be able to observe the early universe because all of the really interesting things have been redshifted from what was once visible light into the infrared.
Dr. Pamela Gay: Right. So we’re able to start seeing things like that Lyman alpha hydrogen line that you mentioned in the infrared at this particular distance. Now, the other thing they’re doing that I have to admit, I didn’t know about until I was prepping for this show, is they are also looking for where is water being annoying and in the form of ices on dust, absorbing light out.
Fraser Cain: You know what, let’s talk about that in a second, but it’s time for me to break. All right.
Dr. Pamela Gay: So the other thing they’re doing is they’re acknowledging that dust has this nasty habit of collecting ice on it. And ices have a nasty habit of absorbing chunks of light out of starlight. And so they’re looking to map out where is there water in our galaxy by looking for those absorption bands in starlight.
So along with 450 million galaxies, because that’s not enough to do, they are also looking at a large sampling of stars and mapping out the ices in our galaxy. And this is what’s cool about having it in a polar orbit is it’s going to get the entirety of the sky.
Fraser Cain: Right. Right. And, and so like, what role do we think these ices play in, in planetary formation and in star formation?
Dr. Pamela Gay: You, you have to have stuff heavier than hydrogen helium and ices count is heavier than hydrogen helium in order to start getting planets. And one of the things they’re most interested in is following the water. This is something that scientists are doing in so many different ways.
Mostly we talk about following the water when we’re talking about Mars or looking at moons and asteroids. But in this case, they’re following the water all the way back to the ices that are on dusts. And this also starts to help us understand how is dust in all of its different annoying ways affecting our ability to look out through our galaxy.
One of the reasons that you go to the infrared wavelengths is because dust is less of an effect. In general, when we’re studying the entire universe beyond our galaxy, our view is reddened by the dust in our galaxy, changing the color of things that we’re looking at and not doing it in a consistent way because dust in the galaxy, like dust in my house is clumpy. There are places where there is more, there are places where there is less.
And depending on how much dust is there, the actual color of the object behind has changed.
Fraser Cain: And so, you know, as our great telescopes are now showing us, say, protoplanetary formation, nebulae, we’re watching and seeing, you know, we can’t look back at the history of our own solar system, but we can look at examples of other solar systems out there at different levels of evolution. Okay, this is what we probably looked at right at the very beginning. And so, as SPHERICS is doing this mapping of the sky, it’s going to be revealing all of these places where these ices are forming in these giant molecular clouds that will then evolve into the stars and planets, like places like our solar system.
And so, it’s sort of like a nice add-on to both looking at the very most distant regions of the cosmos, but also much closer to home and showing us our own origins.
Dr. Pamela Gay: And what I love about this is, like I said, it’s extremely complementary to what’s going to be done by the Roman telescope, when, if it launches, please do not cancel that, talk to your Congress critters, and what JBST is able to do. It is low-resolution spectroscopy, but it’s able to see, it’s able to punch above its weight. It’s a tiny, tiny satellite, and it’s able to see deeper than you would expect because it’s looking such broadband.
Yeah, it’s going to find where are the interesting places, where are the cool things, and because it’s all sky, it’s not going to miss anything. And Roman will be able to follow up and say, okay, so we know this is interesting, let’s look here now. And that ability to look deeper, higher resolution with Roman, look even deeper, look even higher resolution with JWST, it allows us to get a faster, better picture than if you had to go hunting for things with Roman, go hunting for things with JWST. Right.
Fraser Cain: Yeah, it’s really interesting that there really are these two classes of missions now, that on the one hand, you have these wide field surveys that aren’t incredibly powerful telescopes, but they’re equipped in a way to find everything that’s happening. And we saw this, obviously, with, say, Gaia, you know, Gaia was observing all of these stars, and then astronomers have used that for calculating the number of white dwarfs in our vicinity and watching his stars or, you know, trying to understand the evolution of the Milky Way and so on. And then you have these snipers, right?
Things like the upcoming extremely large telescope, the Hubble Space Telescope, James Webb, these are monumentally powerful telescopes, but you are looking through a straw. And you don’t have time to look at all of the targets at the same time. So instead, you have this one-two punch, you have things like TESS, which are finding exoplanets, Kepler, wide surveys, finding lots, lots, thousands, potentially planets, and then you filter them down for the best stuff.
And then you do your following observations with the telescopes like James Webb and so on. And so SphereX, again, you know, there’s really this unfolding mystery that, you know, we’ve been reporting on for the entire duration of AstronomyCast, which is how have dark matter and dark energy evolved over the age of the cosmos? How do they play into the large scale structure of the universe?
We’re seeing such a great response now with SphereX, with the upcoming Vera Rubin, with Euclid, with hopefully Nancy Grace Roman, the DESI survey, all of these instruments all coming together, are going to look at this mystery at different versions, and I, you know, different aspects. And I really feel like, you know, a lot of the mystery, a lot of the uncertainty will go away. We’ll be left with certainty about the characteristics of these things, and we don’t know what they are yet, but at least we’ll know with certainty how they behave.
Dr. Pamela Gay: And this is the season that we also will be getting the Large Synoptic Survey Telescope, which is now the Vera Rubin Observatory and the Large Space and Time. There’s the Legacy Survey for Space and Time. Yeah, LSST. This is the season we’re finally going to get to talk about that as well. We’re just going to have to wait about one more month. So bear with us. That too is coming.
We just are all, like everyone currently is living in terror because LSST is predominantly funded through NASA and NSF. So again, call your Congress Critters. This is going to be an ongoing theme and the topic of our next to last episode of the season.
Fraser Cain: Yeah. But yeah, a cool mission. We’re at the very beginning stages.
So how will SPHEREx play out now over the next couple of years?
Dr. Pamela Gay: It is literally just going round and round the planet. They will be doing data releases. But the thing I love about these kinds of missions is once they get into space, you don’t exactly know how long they’re going to last.
This isn’t going to be something that lasts decades longer than we had hoped for, simply because it is in low Earth orbit. So that means its life is finite. But there’s a chance that we will get even more passes than the two years for passes that are planned.
I have my fingers crossed.
Fraser Cain: Right. We’ve heard this story before.
Dr. Pamela Gay: Yeah.
Fraser Cain: As NASA designers undersell the long lived nature of their missions.
Dr. Pamela Gay: Yeah. There’s like 18 Earth science missions currently up there of which all but four are well past their expiry date. So you can just ignore the best by dates on all NASA spacecraft.
Fraser Cain: Yes. I love that. All right.
Well, that was very cool. Thanks, Pamela.
Dr. Pamela Gay: Thank you, Fraser. And thank you so much to all of our patrons out there. You guys allow this to keep going week after week.
This week, I would like to thank a pronounceable name. Abraham Cottrell, Adam Anise Brown, Alan Gross, Alex Rain, Andrew Allen, Andrew Palastro, Andy Moore, Bart Flaherty, Benjamin Davies, Brian Kilby, Kem Urasian, Cody Rose, Conrad Haling, Daniel Donaldson, Iran Zegrev, Frodo Tannenbaum, G. Caleb Sexton, Greg Davis, Greg Violet, Gregory Singleton, Happy Goro, Jason Kwong, Jean Baptiste, Jeanette Wink, Jeff Wilson, Jim McGeehan, Jim of Everest, J.O., Jonathan H. Staver, Kim Barron, Larry Doetst, Lana Spencer, Marco Arasi, Mark Phillip, Mark Steven Raznick, MHW1961, Super Symmetrical, Michael Plasma, Michelle Cullen, Nick Boyd, Olga, Red Bar is watching, Ryan Amari, Simon Parton, Stephen Miller, TC Starboy, Tasha Nakini, and William Andrews. Thank you all so very much.
Fraser Cain: Thanks, everyone. And we will see you next week.
Dr. Pamela Gay: Bye-bye, everyone. Astronomy Cast is a joint product of Universe Today and the Planetary Science Institute. Astronomy Cast is released under a Creative Commons attribution license.
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