Gaia data works its way into so much science. It really has made a foundational contribution to astronomy.

I use a free astronomy software called Cartes du Ciel. It uses no star catalogs other than GAIA DR3. I have nearly every star in the sky down to magnitude 21, with full astrometry on every star. Distance (parallax), spectral type, proper motion, radial velocity, and GAIA catalog number. No matter what telescope I use there's no star in my eyepiece that isn't in Cartes du Ciel with GAIA DR3. GAIA has constructed a 3D map of the Milky Way in motion to analyze star associations, origins and destinations. GAIA discovered that several billion years ago, the Milky Way ate a smaller galaxy called Gaia Enceladus, whose stars are different than native Milky Way stars, both in motion and chemistry. By coincidence our solar neighborhood is particularly dense in nearby Gaia Enceladus stars. The sun, however, and our solar system are native Milky Way.

Thanks for this amazing interview! And greetings from the ESA Control Center in Darmstadt, Germany! I actually started watching the video from the room where Gaia is operated. A colleague just send me this video in the moment I was investing an issue with the Mission Control System… Anyways, in case you can’t get enough of Gaia - there is also a lot of interesting facts about operations of Gaia. Just two examples: To make a super-precise observation, you not only require crazy accuracy in both orbit and attitude - you also need perfect time stamping of your observations! Therefore Gaia even has an atomic clock onboard! Also, there is periods of time during which the Galactic Plane enters Gaia’s field of view. As Gaia is tracking every single bright object, it generates much more data than usual which can be more than 60gb per day! To downlink all this data we require 24/7 groundstation coverage to somehow get all data downlinked to Earth.

Amazing! The more technical Dr Holl gets, the more amazing the engineering is revealed to be.

The animation of how the CCD collector works, showing how the precise rotation rate allows for the operation of the telescope, and why it can’t continue science operations without refueling was a particularly interesting part of the conversation.

One of the best episodes. It's obvious your interest in the topic. What made this episode is you let him talk and discuss. Very well done Fraser. This was, in my opinion opinion, your best interview.

I really appreciate that Dr. Berry Holl, got super technical. I wish he would have kept talking. I'm not an expert in this area, but it's super interesting to me.

Berry was very informative! THANK YOU SO MUCH!

Hey Berry, great talk. I enjoyed it 😁

Thank you so much for this beautiful interview, it is so nice to hear two persons speak with so much passion about what they love. Dankjewel Dr. Berry Holl

He looks like the mystery character in an old Superman movie, who you think is going to be a villain, but then in Act III he saves the day

Aloha. Yep. GAIA rules. It helps so many astronomers from all corners of their subject.

Dr holl is so interesting i hope that he will comeback for another itw soon

Your interviews are great, Fraser and team. Thank you for your hard work.

I love GAIA too.

That was great to also hear all these technical details, shows how much work goes into these missions to get out the best quality results. Just amazing

Summary: Mission Overview: - (0:00) Gaia is a space telescope mapping the Milky Way by observing the positions, motions, and properties of billions of stars. - (0:18) It provides a comprehensive 3D map used for diverse astronomical discoveries. How Gaia Works: - (6:49) Located at the L2 Lagrange point, Gaia orbits the Sun alongside Earth, avoiding obstruction by the Earth and Moon. - (7:07) It spins every six hours and uses two telescopes with a wide field of view, observing every part of the sky multiple times over its mission. - (7:53) The resulting data is sparsely sampled, creating challenges for analysis but providing rich information. Gaia's Capabilities: - (11:28) Astrometry: Gaia precisely measures star positions and distances using parallax, achieving unprecedented accuracy. - (13:00) Proper Motion: By observing stars over time, Gaia detects their movement across the sky. - (16:42) Radial Velocity: A spectrometer measures the stars' motion towards or away from us (redshift). - (18:49) Photometry and Spectroscopy: Two photometers provide data on star brightness and color, aiding in classification and rough chemical composition analysis. Limits of Gaia: - (22:28) Limited by its sensitivity, Gaia can only observe about 2 billion stars, representing 1% of the Milky Way. - (23:48) Although capable of detecting exoplanets, its sensitivity limits discovery to larger planets like Jupiter and above. - (40:41) Gaia's mission will end soon due to depleting thruster gas, expected in early 2024. What Comes Next: - (49:13) Gaia NIR: A proposed successor mission aims to perform similar observations in near-infrared wavelengths, enabling observations of stars hidden by dust and expanding the survey's reach. - (55:09) Other Potential Missions: Future possibilities include even more sensitive astrometry missions and space-based interferometry to directly image exoplanets. Surprising Discoveries: - (33:02) Gaia has enabled the measurement of the Solar System's acceleration around the galactic center. - (35:37) It has revealed stellar streams and groups, providing evidence of past mergers with the Milky Way. - (34:24) Gaia data contributed to mass estimates of the Milky Way based on the velocity of stars on escape trajectories. - (30:18) An unexpected discovery was the classification of many galaxies based on their variability as a function of Gaia's scanning angle. Overall Impact: - (38:25) Gaia has provided a wealth of data, democratizing astronomy by making it accessible to a wider range of researchers. - (37:52) It has led to a deeper understanding of the Milky Way's structure, evolution, and stellar populations. - (41:51) Gaia's legacy will continue to fuel astronomical discoveries for years to come. i used gemini 1.5 pro

Your interviews and content overwhelm me with joy.

LOVE GAIA, Loved this interview! Thanks guys!

Super interesting, especially the technical details.

This is awesome. But I'd like a little more examination of near Earth objects. Like the asteroid belt that caused the tunguska event and wiped out an Advanced civilization 12,000 years ago Maybe we could map that out. There's still a bunch of really big chunks.

Great episode, many thx

His hair is magnificent

This upload gets a big WOW! Good job Mr. Cain. My favourite too. GAIA, parallax is beyond imagination.

YESSS, Gaia is the absolute best!!!!

Thanks Berry. Thanks Fraser.

Gaia for president!

Very interesting, thank you !

Wow... the best interview ever. 👍

Would be great to do a technical deep dive into the engineering (HW, SW & Mech) used to build and run GAIA. Just a few tantalising hints in this video!

GAIA makes a beautiful spirograph

this interview was by a lot my favorite. from interesting and exotic findings to complex engineering and programming, Dr Holl explains it all

*SPACE EXPLORATION LEADERBOARD* The telescope laypeople know about: Hubble, and now JWST The telescope that gets mentioned in basically every astrophysics topic: GAIA The telescope which is the most under-rated: Chandra XRO The telescope which is the most hyped: JWST, and now Vera Rubin The telescope which has surpassed its original mission objective by the largest margin: Voyager 1, Hubble, or Opportunity depending how you measure it The shortest-lived telescope to collect groundbreaking data: Venera 7, Galileo Entry Probe, or Huygens _I realize that I'm really stretching the definition of telescope at this point._

Eventually it was put in words. About 40% of all future papers will be written based on Gaia. There was the project leader in house of astronmy in Heidelberg some years ago ... somply great!

Once again, great interview 👍. They are my favourite rock band 😬

he's fascinating. more !

What comes next? I like Dr. Holl's hope for an instrument that can get angles 100 times more precise than Gaia. If we can solve the highspeed data problem over distance, it might be good to have three or more identical probes at the Sun-Saturn L3, L4, and L5 points. This would let us get accurate parallax well beyond the distance of the Small Magellanic Cloud, and very accurate distances to stars on our side of the galaxy. We could probably get that together by 2060, with results around 2070. Longer term, if we could get similar instruments around Proxima Centauri, Barnard's Star, and Wolf 359, we'd be able to get accurate parallaxes to the nearer quasars and be able to highly refine our cosmological models.

My ideal next generation GAIA has a reasonable cost by using starship and economy of scale. As you described, a wider parallax baseline (past Saturn orbit) using multiple Gaia telescopes and simultaneous measurements from 2 GAIAs. Larger mirrors to improve sensitivity by several magnitudes, infrared to look through dust. And make each GAIA a dual mirror interferometer telescope to greatly increase angular resolution of the telescope in the baseline direction. High resolution spectrums could be done with a different telescope optimized for this purpose (I.e. larger mirror for more light to shorten shutter exposure times, wider range of wavelengths, precision spectrum sensors that process multiple stars simultaneously, L2 location). Starship could launch these space telescopes at a low cost. Cost per telescope is greatly reduced by producing 6 of them instead of just one. Operating cost per telescope is the greatly reduced because one team is managing all 6 of them instead of just 1) The benefits to Astronomy include understanding our galaxy, understanding stars, understanding dust. M6 favorite benefit is obtaining data that quantifies discrepancies in Newton’s law of gravity, thereby allowing correcting gravitational theory plus proving the corrected law of gravity.

When both share the screen at same time is better in my opinion.

Hi Fraser Classic legrange question here. Could we not divide the time taken for a future Tess-like survey by three if we stationed identical satellites at legrange points 3,4, and 5? For a mars size orbit it would be 229 days per survey, for Jupiter it would be 4 years. What is more important with these kinds of mission? The extra parallax distance or the frequency of datapoints?

Once it runs out of thruster fuel, can the optics be used in a lesser capacity until the craft stops functioning?

One of your best interviews, sointeresting. I too think Gaia is the grestest!

What an amazing machine that telescope is.

Great video again Fraser...I had you wrong... I thought you were obsessed with DUST!!

Would it make sense to send up a Gaia satellite (or two) to Lagrange point(s) in Neptune's orbit to get a much wider arc to determine the position of stars?

We need 4x GAIAs put in solar orbit around Jupiter or Saturn distance for greater parallax. Or Pluto for multi generational studies. And I say 4x because we need to look perpendicular to the ecliptic as well.

Question: Hypothetically speaking, what's the best resolution image we could make of a terrestrial exoplanet, given all the photons from it that arrive at Earth over an entire year?

I like this Spaniard. He is humble and wants to give more info but knows he will suffer. He will probably be running the Spanish Space Admin in the next 20 years.

Hey, long time lurker. Recently learned that the moon had an albedo like asphalt. What if it was as reflective as snow? How bright would the night get?

re - 26:00 More time = better results. I would have liked to have known if the improvement in results over time is a linear progression or an algebraic progression.

I know Gaia doesn't operate in the ideal frequencies, but were any observations of Oumuamua made by Gaia? Would a longer wavelength IR version of Gaia (GaiaIR+) be good for cataloging near Earth asteroids?

(removing question, it was answered late in the interview. Whoop! So here's a new one...) To what extent have we run into the theoretical resolution limit (1/2 wavelength) for visible-spectrum light? With 2 meter telescopes (i.e. Hubble) at 500nm, that's the 60 milliarc-seconds mentioned.

Wow, the deviation of the solar system from its obit is cool. But does it mean that it deviates 100 km per year in the direction AWAY from the center of our MW? And how come, is there a lot of mass there that tugs on the sun? Or is it because we are less bound to other stars because we are a little bit above the arm and therefore are a little less following the stream of motion of the stars in the arm? Or are we accelerating because we are on our way of diving into the arm?

❗️ @1:00:00 EXACTLY what I’ve been asking: constellation of satellites at L2, L4, L5 of BOTH Jupiter and Mars - that also have laser distance relay among themselves for precision, accuracy, AND as a super LIGO. Better parallax, better detail as a super constellation of cross-coordinated satellites, and as a virtual super large telescope resolution. ALSO, launch TWO PAIRS (4 total) Gaia-class missions into a polar-Z directions BOTH ABOVE AND BELOW from the solar system plane (in 20 years, the parallax will be insanely detailed). Perhaps launch them in a train as a relay network. And laser based data transfers. I CAN IMAGINE using several Space-X Starship as the central communications hub that each of these constellations use as the primary data relay to Earth.

Didn't he say Gia has a brightness detection of 21 and higher ? I wonder if seeing dimmer stars fill in the empty space more than near IR. North Star or Pole Star. With an apparent magnitude that fluctuates around 1.98 Maybe those are different ways of measuring

@frasercain Just as the earth has periodic meteor showers due to its path around the sun, can the Gaia data tell us when in the solar system's galactic travel it might have experienced or will experience greater meteor collisions? The path around the black hole that is depicted and the discussion of the cluster passing through the milky way is suggestive that there may be points in our galactic orbit that may be more dangerous than others.

I keep hearing about primordial black holes that are the size of atoms. If I got that right how does something that small have enough mass that light can’t escape? What happens if it runs into say a large iron asteroid does it swallow up the asteroid, or does the mass of the asteroid overwhelm the black hole and cause it to evaporate?

I have a question: I know that in order to determine the shape or the universe there are two ways; either draw a *giant* triangle and measure the sum of its angles or see if two parallel lines stay parallel. How on earth (pun intended) did we do that?? Surely I'm missing something. Can you please explain?

Given the extended mission length will the motion of the solar system within the Milky Way galaxy give a longer baseline than the 2 AU baseline formed by rotation about the sun?

Very nice guest. Good job Fraser!

I love telescopes. Wish we spent more on them.

Please get Technical! :D

I was not sure if this is the right place to ask to get my question picked up but, I just watched the Anton petrov video on glueon balls, could they account for part of dark matter?

GAIA is great and all… but so much better is possible. GAIA is limited in that the parallax measurements take six months between shots. It’s like any of us closing one eye, memorizing the scene in front of us, then switching eyes. That humming bird that just flew by will seem gigantic and far away or teeny tiny and very close depending whether it’s flying left-to-right or right-to-left. In the same vein that we use both eyes at the same time next-GAIA should have more than one eye open all the time. We need GAIA cameras at all the compass points around the solar system and off the solar system’s north & south poles. And it could get better all the time by having each travelling at escape velocity outward so the parallax baseline keeps getting longer. Multiple cameras measuring parallax continuously means catching short-lived wobbles in real-time.

So Gaia discovered a Black Hole with a star orbiting around it. Then the illustration shows the Black Hole orbiting around a "center of mass". Wouldn't the Black Hole itself, be the center of mass????

Love GAIA! There's an animation of the stars moving around near our solar system, made using the GAIA data - nearly gave me an anxiety attack.

Where is this week's question show?

What is the Gaia estimate of the mass of the Milky Way?

With such a finely-detailed, wide angle general survey; is anyone looking out for "Planet X", or other solar-system objects? Surely their images must be captured too.

I have no understanding of how 3d cameras work. But it makes me think, is a 3d telescope possible?

📍 Astrometrics lab (like Seven of Nine or Data’s labs in Star Trek) will be great. Overlay of all types of data from the glass plate photos, Hubble, etc. for query and hypotheses. Even raw data and alternate noise reduction models from Gaia. Artificial Intelligence , etc. ❓ I’m curious how various standard candles are used to maintain calibration. If distant galaxies are stable in color and position, then correlate the data capture on Gaia’s angle of data collection…

Wouldn't it be more cost-effective to send refueling missions to rendezvous with our multi-billion dollar spacecraft (presuming we would design them to accommodate such missions), doubling or tripling their effective mission lives?

If a singularity is an infinitesimal point, why doesn’t it have infinite spin after a star collapses to form it? You know, with the conservation of angular momentum and all… ?

Gaia rotates 60 arc seconds per second, so I guess that the stellar images on the detector are not points but lines, right?

Your favorite until Vera Rubin comes on line next year. No disrespect to Gaia it’s amazing too.

I think we should make another guy to send out because it is an awesome satellite observer

It blows my mind how much data Gaia has collected over the time of it's mission. I can't help but imagine AI programmes finding new discoveries where humans wouldn't have the time to process all the data.

Russell's Tea Cup?

We really should put telescopes to L4 & L5 of Jupiter for a good parallax

How was your trip to Japan?

Sooooo, james Web can't be refueled?

GAIA

Your right Fraser i think Gaia is incredible. Do you ever watch The Sky At Night the BBC astronomy show they did great episodes 1 before Gaias launch and another in 2018.

If we were going to plan to populate the galaxy, where should we head with our von Neumann probes after the nearest stars? Inwards along the galactic arm or hop over towards the next arm?

Gaia is such a success we should create a better version.

Stereotypical 90s action movie German bad guy.

Do black holes eat dark matter (seems like they should since gravity is a dark matter clue) and if so why can't we learn more about it by studying this?

Where are the 30k exoplanets that were promised to us?

He admitted the Gia team withholds information. I'm starting a rumor that the Gia team is withholding the discovery of a Cryogenic Rouge Planet is heading to an Earth Collison

Paralex of 2 AU, not 1

If it were left up to me, I would already be setting up a telescope the size of mars to the earth so it's Fraser Cain doable.

Does your fiancé watch your video? When you say I can afford to lose it, she is help with that comment. Noticed things are moving back up in you office. 😀

Does the phrase "black hole" inspire the same kind of jokes in Russia that the name of the planet Uranus does in the English-speaking world?

It's designed to attempt to find the gender pay gap.

Sorry. Hubble is undisputed to me.