Ask a Spaceman!

AaS! 262: Does the Universe Have Extra Dimensions?

16 Dec 2025

Contributed by Lukas

What do extra dimensions have to do with the strength of gravity? What is a tower of gravitons? How can we detect extra dimensions even if we can't pe...

AaS! 261: What are Black Dwarfs?

02 Dec 2025

Contributed by Lukas

What happens to a white dwarf when it cools off? How long does it take? Do they just stay black forever, or will something more interesting happen to ...

AaS! 260: What's the Big Deal with the Weak Force?

18 Nov 2025

Contributed by Lukas

How did we discover the weak nuclear force? Why is it so strange compared to the other forces? What do mirrors have to do with all of this? I discuss ...

AaS! 259: Where Exactly is the Edge of the Universe?

04 Nov 2025

Contributed by Lukas

Is the universe infinite? What about the cosmological horizons, the limits to what we can see? Will we ever know for sure what's beyond them? I discus...

AaS! 258: What's Going to Happen After the ISS?

21 Oct 2025

Contributed by Lukas

Why did we develop the International Space Station in the first place? What have we learned in its 25+ years of operation? When is it coming down, and...

AaS! 257: How Does One Go About Smashing Particles?

07 Oct 2025

Contributed by Lukas

How do particle colliders work? What kinds of energies are we talking about? Are there any uses for colliders except for physics experiments? I discus...

AaS! 256: What Can Gravitational Waves Teach Us About the Big Bang?

23 Sep 2025

Contributed by Lukas

What are some sources of gravitational waves that aren't black holes? How did inflation create gravitational waves? How can we possibly detect them? I...

AaS! 255: How Do the Biggest Stars Get So Big?

09 Sep 2025

Contributed by Lukas

How do we measure the sizes of stars? What are the biggest ones today, and how big could stars have gotten in the past? Is there any way for a star to...

AaS! 254: How Do Variable Stars, You Know, Vary?

19 Aug 2025

Contributed by Lukas

What powers Cepheid variable stars? What about Mira variables and pulsating stars? And are there variable stars that don't actually vary at all? I dis...

AaS! 253: What Does Outer Space Sound Like?

05 Aug 2025

Contributed by Lukas

What would the Sun sound like if we could hear it? Does any noise at all happen in the universe? What's the biggest sound of all? I discuss these ques...

AaS! 252: Why Can't We Get Free Energy from the Vacuum?

22 Jul 2025

Contributed by Lukas

Why does the vacuum of spacetime have energy? How much energy does it have? What prevents us from using it to do anything useful? I discuss these ques...

AaS! 251: Are the Cosmic Voids Really Empty?

08 Jul 2025

Contributed by Lukas

How do we actually define voids? Are there regions within them that are truly empty? What would it be like to be inside one? I discuss these questions...

AaS! 250: Where Do the Constants of Nature Come From? Part 2

17 Jun 2025

Contributed by Lukas

Part 2 of 2! What are the modern constants of nature? Is the universe fine-tuned for life? Does the multiverse or string theory explain the origins of...

AaS! 249: Where Do the Constants of Nature Come From? Part 1

03 Jun 2025

Contributed by Lukas

Part 1 of 2! How do fundamental constants appear in physics? Why are they so important? Why do we care where they come from? I discuss these questions...

AaS! 248: What's Going on Inside Neutron Stars?

20 May 2025

Contributed by Lukas

What's inside a neutron star? What strange states of matter do we encounter? And what mysteries will we find deep in the core? I discuss these questio...

AaS! 247: How Can We Get Giant Black Holes in the Early Universe?

06 May 2025

Contributed by Lukas

How do we explain the giant black holes appearing in the young universe? Is it possible to directly collapse a black hole, skipping the formation of s...

AaS! 246: What is Stephen Hawking's Legacy?

22 Apr 2025

Contributed by Lukas

How do you measure the impact of a scientist? Does Stephen Hawking compare to Newton or Einstein? What were his contributions to black holes, the big ...

AaS! 245: What Made the Moon?

08 Apr 2025

Contributed by Lukas

Why is the moon so special? Why do we think a giant impact created it? Why didn't the same thing happen to other planets? I discuss these questions an...

AaS! 244: What's the Most Important Wavelength in All Astronomy?

18 Mar 2025

Contributed by Lukas

What is 21-cm radiation? What (and who) produces it? What causes it, and what does it tell us about the universe? I discuss these questions and more i...

AaS! 243: So Is the Warp Drive Legit or Not?

04 Mar 2025

Contributed by Lukas

What is an Alcubierre warp drive? What would it take to make it work? Could it propel spacecraft even below the speed of light? I discuss these questi...

AaS! 242: Are There Invisible Stars in the Universe?

18 Feb 2025

Contributed by Lukas

What is an axion? How could axions make a star, and what does that have to do with dark matter? What would these stars look like? I discuss these ques...

AaS! 241: Could We Travel to Parallel Universes?

04 Feb 2025

Contributed by Lukas

Where do parallel universes exist? Could we use wormholes to travel to them? What does time travel have to do with all this? I discuss these questions...

AaS! 240: Does the Great Filter Explain Why We're Alone?

21 Jan 2025

Contributed by Lukas

What is the Fermi Paradox? How rare is non-intelligent vs intelligent life? What are the challenges a species must overcome to colonize the galaxy? Wh...

AaS! 239: What Are the Weirdest Hypothetical Particles?

07 Jan 2025

Contributed by Lukas

Are dark photons as sinister as they sound? What did the curvaton do in the early universe? And is everything really made of preons? I discuss these q...

AaS! 238: What Makes the Sun's Corona So Dang Hot?

17 Dec 2024

Contributed by Lukas

How can the solar corona be hotter than the surface? What has the Parker Solar probe learned so far? What do magnetic fields have to do with all this?...

AaS! 237: Could Any Supernova Harm the Earth?

03 Dec 2024

Contributed by Lukas

Are we "in range" of any potential supernovae? Has the Earth ever been hit in the past? And what about gamma-ray bursts from across the galaxy, are we...

AaS! 236: How Exactly Do Black Holes Merge?

19 Nov 2024

Contributed by Lukas

How do black holes get close enough to merge? What causes them to emit gravitational waves, and where do the waves come from? What does the merger pro...

AaS! 235: Is it Time to Redefine the Planet?

05 Nov 2024

Contributed by Lukas

How did Pluto get demoted? What makes a planet a planet anyway? Why do we now have so many different kinds of planets, and should we make things simpl...

AaS! 234: How Could We Turn the Sun into a Telescope?

15 Oct 2024

Contributed by Lukas

How do gravitational lenses work? Where would a spacecraft need to be to use the Sun's gravity as a telescope? What could we learn about exoplanets wi...

AaS! 233: Why Do We Care About Methane on Mars?

01 Oct 2024

Contributed by Lukas

What's behind the Martian Methane Mystery? Is it a sign of life, or just some strange chemical process? Or are we just fooling ourselves? I discuss th...

AaS! 232: Is Space Tourism a Good Idea?

17 Sep 2024

Contributed by Lukas

Why are private space companies pushing tourism? Is there a future for tourism in space? Is this an overall good thing for space exploration, or just ...

AaS! 231: What Made the Local Bubble?

03 Sep 2024

Contributed by Lukas

Where do we live within the galaxy? What shapes the local bubble? How long will we be inside it? I discuss these questions and more in today's Ask a S...

AaS! 230: Is the Universe Making Any New Galaxies?

20 Aug 2024

Contributed by Lukas

How do galaxies form and evolve? Is the universe still making new ones? What will happen to the current galaxies in the universe? I discuss these ques...

AaS! 229: Is the James Webb Breaking Cosmology?

06 Aug 2024

Contributed by Lukas

What has the James Webb Space Telescope learned so far? Is it finding galaxies that "break" cosmology? What will we learn next? I discuss these questi...

AaS! 228: Can a Galaxy Be Destroyed?

16 Jul 2024

Contributed by Lukas

Can galaxies ever get destroyed? What happens to their stars? Do galaxies ever die? I discuss these questions and more in today's Ask a Spaceman! Supp...

AaS! 227: Where is the Center of the Universe?

02 Jul 2024

Contributed by Lukas

What does it mean for the universe to have a center? Could we ever travel to ours? What is a singularity? I discuss these questions and more in today'...

AaS! 226: Does the Universe Get Shorter When You Go Faster?

18 Jun 2024

Contributed by Lukas

How does length contraction work in relativity? Do moving objects really get shorter? What about from their perspective? How are we supposed to make s...

AaS! 225: What is the Cosmic Flaw That Shouldn't Exist?

04 Jun 2024

Contributed by Lukas

What is the "cold spot" on the cosmic microwave background? Why shouldn't it exist? What are some possible explanations for it, and why are they unsat...

AaS! 224: Can Life Survive on Locked Planets?

21 May 2024

Contributed by Lukas

How do planets get tidally locked? What are these systems typically like? Can life find a home in such a challenging environment? I discuss these ques...

AaS! 223: Why is it So Hard to Return to the Moon?

07 May 2024

Contributed by Lukas

If we went to the Moon already, why can't we go back so easily? What technology have we lost? What are we trying to do differently? I discuss these qu...

AaS! 222: What is the Most Distant Thing We Can See?

16 Apr 2024

Contributed by Lukas

What's the most distant thing we can see with the naked eye? What about with a telescope? What about at other wavelengths? Is there anything more to s...

AaS! 221: Will Emergent Gravity Rewrite Physics?

02 Apr 2024

Contributed by Lukas

What is "emergence" in physics and why is it a big deal? What would it mean for gravity to be emergent? How would we have to rewrite the laws of physi...

AaS! 220: Will Our Universe End in a Big Rip?

19 Mar 2024

Contributed by Lukas

How can a "big rip" tear the universe apart? What does that mean for existence itself? Is it going to happen, and what are we doing to find out? I dis...

AaS! 219: What's the Best Way to Defend Our Planet?

05 Mar 2024

Contributed by Lukas

How do we track dangerous asteroids? What can impacts do to us? What do we plan to do if The Big One is headed for us? Is Armageddon a documentary? I ...

AaS! 218: How Do We Know What the Milky Way Looks Like?

20 Feb 2024

Contributed by Lukas

Why is it so hard to get a picture of the Milky Way? How much of our galaxy have we mapped? What the heck is a "barred spiral" and what does that have...

AaS! 217: Will We Achieve Fusion Power Soon?

06 Feb 2024

Contributed by Lukas

How do we achieve nuclear fusion in the laboratory? What are some experiments that are trying to achieve fusion power generation? Why is it so difficu...

AaS! 216: Do Aliens Look Like Us?

16 Jan 2024

Contributed by Lukas

Is evolution universal throughout the cosmos? What are the different forms that life can take? When did life first appear in the universe? I discuss t...

AaS! 215: How Does Science Regain Trust?

02 Jan 2024

Contributed by Lukas

What forces people to lose trust in science? How does this affect the process of science itself? What are scientists doing to make this worse? How can...

AaS! 214: Is Empty Space Really...Empty?

19 Dec 2023

Contributed by Lukas

What's floating around in space between all the stuff? Are there any truly empty places in the universe? What is the "fabric" of spacetime? I discuss ...

AaS! 213: How Were Ancient Astronomers So Good?

05 Dec 2023

Contributed by Lukas

How were ancient people able to predict eclipses so well? How did they make predictions without modern science? What were they able to discover? I dis...

AaS! 212: Where Do All the Elements Come From?

21 Nov 2023

Contributed by Lukas

What processes create all the elements? Why are some elements more common than others? How does fusion happen inside and outside of a star? I discuss ...

AaS! 211: Will AI Take Over Astronomy?

07 Nov 2023

Contributed by Lukas

How long have astronomers been using artificial intelligence? How do computers sift through massive amounts of data? Will AI discover something new ab...

AaS! 210: How Does Space Affect the Climate?

17 Oct 2023

Contributed by Lukas

What triggers ice ages and other climate events? How are sunspot cycles and orbital motions related to climate patterns? What does Jupiter have to do ...

AaS! 209: What Secrets Are Hiding in Triton?

03 Oct 2023

Contributed by Lukas

What's so cool about Triton? How did it end up in orbit around Neptune, and what can we learn from it? Could we send a mission there one day? I discus...

AaS! 208: Where Are All the White Holes?

19 Sep 2023

Contributed by Lukas

How are white holes different from black holes? What would happen if you were stuck inside of one? Why don't they appear in the universe? I discuss th...

AaS! 207: How Far Do We Travel in Our Lives?

05 Sep 2023

Contributed by Lukas

What is the combined motion of everything in the universe? How does all of that influence us? Are we just going around in circles, or is there somethi...

AaS! 206: What are the Weirdest Names in Astronomy?

15 Aug 2023

Contributed by Lukas

What are some wild stories behind names in astronomy and physics? How did we get the jargon words that we did? What are some of the funniest names? I ...

AaS! 205: What's the Difference Between Science and Pseudoscience?

01 Aug 2023

Contributed by Lukas

What's the difference between science and pseudoscience? What is a scientific mindset? How are we able to spot pseudoscience when it's happening? I di...

AaS! 204: How did Annie Jump Cannon Bring Order to the Universe?

18 Jul 2023

Contributed by Lukas

How was massive astronomy done in the 1800's? Who were the Harvard Computers? How did Annie Jump Cannon figure out how to classify stars? I discuss th...

AaS! 203: Is the Universe a Giant Black Hole?

04 Jul 2023

Contributed by Lukas

Why didn't the big bang collapse in a singularity? What would a universe-sized black hole be like? Now that I think about it, do we live inside a gian...

AaS! 202: Could the Earth Leave the Solar System?

13 Jun 2023

Contributed by Lukas

Could we nudge the orbit of the Earth to avoid the death of the Sun? Could it get kicked out of the solar system altogether? What are rogue exoplanets...

AaS! 201: How Does Light Slow Down?

06 Jun 2023

Contributed by Lukas

If light always travels at the speed of light, how does it slow down when passing through air or water? Does it matter if light is made of particles o...

AaS! 200: What are the Top 5 Mysteries in Astronomy?

16 May 2023

Contributed by Lukas

What are the biggest mysteries facing modern astronomers? What questions do I wish could be answered in my lifetime? What are most astronomers working...

AaS! 199: What are the Top 5 Discoveries of All Time in Astronomy?

02 May 2023

Contributed by Lukas

What discoveries and insights made the biggest impacts in astronomy and physics? What were the biggest surprises? What results took the longest to ach...

AaS! 198: What's So Weird About Black Hole Shadows?

18 Apr 2023

Contributed by Lukas

How does a black hole make a shadow? What can we learn from it? What are we seeing when we look at a black hole? I discuss these questions and more in...

AaS! 197: Which is Better, Human or Robotic Exploration?

04 Apr 2023

Contributed by Lukas

What are the advantages of robotic exploration of the solar system? What are the limitations? Is there any situation where human exploration is better...

AaS! 196: Could We Ever Build a Dyson Sphere?

21 Mar 2023

Contributed by Lukas

What are Dyson spheres? What would be involved in building one? How much energy would it cost, and could we ever pay it back? I discuss these question...

AaS! 195: How Cold Can Space Get?

07 Mar 2023

Contributed by Lukas

What's the temperature of deep space? Can it get any colder than that? How do we even define temperature when there's nothing around? I discuss these ...

AaS! 194: Does the Universe Rotate?

21 Feb 2023

Contributed by Lukas

How do we know that the universe doesn't rotate? Why would it matter if it did? What does all this have to do with time travel? I discuss these questi...

AaS! 193: What are the Blue Stragglers?

07 Feb 2023

Contributed by Lukas

What are blue straggler stars? How were they first discovered? What do they tell us about star clusters and the evolution of stars? I discuss these qu...

AaS! 192: Can Tachyons Exist?

17 Jan 2023

Contributed by Lukas

Is it possible for anything to travel faster than light? What about tachyons? How would faster-than-light travel break causality? And just what the he...

AaS! 191: What is the Meaning of Quantum Mechanics? (Part 9: Both/And)

03 Jan 2023

Contributed by Lukas

Part 9! What is the role of consciousness in quantum mechanics, if there even is one? Is there any way at all to develop a coherent view of nature bas...

AaS! 190: What is the Meaning of Quantum Mechanics? (Part 8: For Nothing is Hidden)

20 Dec 2022

Contributed by Lukas

Part 8! What is real in quantum mechanics, and what are mere mathematical tricks? Can the probability waves be real, and what would that mean? What is...

AaS! 189: What is the Meaning of Quantum Mechanics? (Part 7: Many Worlds, Infinite Possibilities)

06 Dec 2022

Contributed by Lukas

Part 7! What is the many-worlds interpretation of quantum mechanics? How does decoherence play a critical role? What are the strengths and weaknesses ...

AaS! 188: What is the Meaning of Quantum Mechanics? (Part 6: Einstein's Revenge)

15 Nov 2022

Contributed by Lukas

Part 6! What were Einstein's objections to quantum mechanics? Why was he so bothered by non-locality? What is the EPR paradox? I discuss these questio...

AaS! 187: What is the Meaning of Quantum Mechanics? (Part 5: Dreams of Copenhagen)

01 Nov 2022

Contributed by Lukas

Part 5! What is the Copenhagen interpretation? How did the debates between Heisenberg and Schrodinger influence later physicists? What are the strengt...

AaS! 186: What is the Meaning of Quantum Mechanics? (Part 4: It's a Quantum, Quantum, Quantum World)

18 Oct 2022

Contributed by Lukas

Part 4! What are the basic lessons of quantum mechanics? What does quantum mechanics teach us about the nature of reality? How does a quantum worldvie...

AaS! 185: What is the Meaning of Quantum Mechanics? (Part 3: There and Back Again)

04 Oct 2022

Contributed by Lukas

Part 3! Who developed quantum theory and why? What experiments motivated the creation of quantum mechanics? How was quantum mechanics a total break fr...

AaS! 184: What is the Meaning of Quantum Mechanics? (Part 2: Quantum Mechanics 102)

20 Sep 2022

Contributed by Lukas

Part 2! How do physicists understand quantum mechanics? What are the postulates and principles of quantum mechanics? How do the foundations of quantum...

AaS! 183: What is the Meaning of Quantum Mechanics? (Part 1: This Way to the Weird)

06 Sep 2022

Contributed by Lukas

Part 1! Where does quantum theory fit in the larger tapestry of physics? What is the domain of quantum mechanics? And most importantly, what are the l...

AaS! 182: Wait, Super-Atoms are a Real Thing?

16 Aug 2022

Contributed by Lukas

How do you make a super-atom? What can they be used for? What does this mean for quantum mechanics? I discuss these questions and more in today's Ask ...

AaS! 181: What is the Principle of Least Action?

02 Aug 2022

Contributed by Lukas

What makes the principle of least action so important? Who came up with it? Is it all just a bunch of math or does it actually mean something? I discu...

AaS! 180: How Does Pulsar Timing Work?

19 Jul 2022

Contributed by Lukas

What is a pulsar? How can we use them to map gravitational waves? What kind of technology does it take? I discuss these questions and more in today's ...

AaS! 179: What are the Alternatives to Dark Matter?

05 Jul 2022

Contributed by Lukas

What are some of the problems with dark matter? What about modified gravity? Are there any other solutions? I discuss these questions and more in toda...

AaS! 178: How Big Can Planets Get?

21 Jun 2022

Contributed by Lukas

How big can a rocky planet get? Can a rocky planet turn into a gas giant? Why are some planets rocky and others gassy? I discuss these questions and m...

AaS! 177: How Do Black Holes Affect Their Galaxies?

07 Jun 2022

Contributed by Lukas

How do giant black holes shut off star formation? How do they turn it back on? Which came first, the black hole or the galaxy? I discuss these questio...

AaS! 176: Why is Gravity So Weak?

17 May 2022

Contributed by Lukas

How did gravity get so ridiculously weak? Could it be related to extra dimensions? What does string theory and the concept of the "bulk" have to do wi...

AaS! 175: Should We Be Afraid of the Dipole Repeller?

03 May 2022

Contributed by Lukas

What is the dipole repeller? Why is it a dipole? What is it repelling? What is the Bootes Void and how is it connected to dark energy? I discuss these...

AaS! 174: What Solves the Twin Paradox?

19 Apr 2022

Contributed by Lukas

What does everybody think is the twin paradox? What's the REAL twin paradox? How is the paradox resolved, and what does it teach us about synchronicit...

AaS! 173: How Does Radioactive Decay Work?

05 Apr 2022

Contributed by Lukas

How was radioactive decay discovered? What are the different kinds of decay? How does quantum mechanics make all this happen? I discuss these question...

AaS! 172: What Are Some Alternatives to the Big Bang Theory?

15 Mar 2022

Contributed by Lukas

What makes the Big Bang theory so successful? How were alternatives ruled out? What are the electric universe and steady state theories? Do any other ...

AaS! 171: What are Lagrange Points?

01 Mar 2022

Contributed by Lukas

Why are Lagrange points so crucial to astronomy? What makes even simple gravity so difficult? How do you "put" something at a Lagrange point? I discus...

AaS! 170: What's So Fine About the Fine Structure Constant?

15 Feb 2022

Contributed by Lukas

What is the fine structure constant? Where does it come from? Why is it so important? I discuss these questions and more in today's Ask a Spaceman! Su...

AaS! 169: What Is Loop Quantum Gravity?

01 Feb 2022

Contributed by Lukas

Why do we care about loop quantum gravity? Is it a viable path to uniting quantum mechanics and general relativity? What does it mean for spacetime to...

AaS! 168: Can We Get Some Love for Globular Clusters?

18 Jan 2022

Contributed by Lukas

How are globular clusters so old? Where did they come from, and how are they linked to galaxy formation? What makes them so globular, anyway? I discus...

AaS! 167: Do We Live In a Giant Simulation?

04 Jan 2022

Contributed by Lukas

What is the simulation hypothesis? Is it just pseudoscience? How do we grapple with its implications? I discuss these questions and more in today's As...

AaS! 166: What's the Truth Behind 'Oumuamua?

21 Dec 2021

Contributed by Lukas

Where did 'Oumuamua come from? What is it made of, and how did it end up here? Is it really an artifact of an alien civilization? I discuss these ques...

AaS! 165: What Comes After the James Webb Space Telescope?

07 Dec 2021

Contributed by Lukas

What missions will come after the James Webb Space Telescope launches? What new discoveries await us? How long will they take to start? I discuss thes...

AaS! 164: Where Can We Find Diamond Rain?

16 Nov 2021

Contributed by Lukas

How do giant planets make diamond rain? Does it really, you know, rain? Where does diamond rain exist? I discuss these questions and more in today's A...

AaS! 163: Will Our Universe End in a False Vacuum Decay?

02 Nov 2021

Contributed by Lukas

What is a vacuum, and what makes a false one? What happened in the early universe to bring about our current physics? Will it happen again? If so, whe...