David Kipping

Thanks, was a trip!

I actually did (towards the end)! Maybe they cut it?!

Jerk Carl Sagan: We’re all star shit

YouTube video by Cool Worlds Podcast #24 Colin Hill - Modern Cosmology, Hubble Tension, Exotic Physics

youtu.be/FkC-kVC2IRA?...

Ye even for 100% efficiency you’re looking at 5% of the entire planet’s electricity. Record efficiency to date is 7.8% so that means you need more than half the planet’s electricity. (Plus imagine the infrastructure needed)

Well it’s basically a very thin film rapidly rotating so my guess is that it would progressively shed from the outside in, essentially disintegrating. I don’t see this as a threat to Earth because the masses are so low it would all burn up. Could cause Kessler syndrome though if not careful.

a close up of a man 's face with the words c ' mon tars written on it . ALT: a close up of a man 's face with the words c ' mon tars written on it .

The paper is at arxiv.org/abs/2507.17615

I don't know if TARS would work or not, but interstellar flight is a personal dream & so I felt compelled to try. This isn't as fast as Starshot but should be far easier to make. Mostly, I hope this inspires others to work on this problem!

The magnetic field produces in this configuration could actually be useful in its own right, such as providing protection to a Mars base for example. And given these things weigh just ~kg, made of existing materials and powered solely by the Sun, we could make a lot of them.

We speculated that even faster speeds could be obtained by electrically charging the tips, providing a restoring force. This creates a rotating dipole that radiates and the new terminal speed is set by energy balance, and is ~1000 km/s (0.3% c!) - again just using the Sun!

A chipsat, similar to that proposed by Breakthrough Starshot, is released just before breakup, flying off in a tangential trajectory out of the Solar System. In principle we could boost the speeds by using eccentric orbits + Oberth effect, graphene sheets and gravity assists.

After ~3 years @ 1AU, TARS would spin up to 12.1 km/s which is the critical velocity when the centrifugal force exceeds the tensile strength of the CNT sheets. Adding on the quasite orbital velocity, the ends are moving at 40.4 km/s - exceeding the Sun's escape velocity.

The whole thing is scalable but our paper considers the example of a 63m x 7m x 2.6um design weighing 1.6 kg made of CNT sheets. The strange dimensions are required for stability against tumbling (T-handle effect). One could imagine TARS being folded up at launch then unfurling.

However, there's also an outward force trying to push TARS away from the Sun, which is bad since radiation pressure drops off as distance^2. So, we combat this by placing TARS in a "quasite" orbit, an idea I came up with in a previous paper: doi.org/10.3847/2515...

The simplest way to understand TARS is to think about something like this, two thin paddles joined by a tether. One side is painted silver & the other dark, with opposite phases. The silver side feels 2x the radiation pressure as the dark side, and thus TARS feels a torque.

New paper! Allow me to introduce TARS = Torqued Accelerator using Radiation from the Sun. TARS (yes inspired by Interstellar!) is a rotating light sail that's capable of launching chip sats into interstellar space using only radiation from the Sun, so let's dive into how it works.

That would be fun, I’ll be around London

Some personal news! Next month I will be moving to the UK for a year for a sabbatical. I plan to do some writing, recharge my batteries, build new connections and make some great videos. Looking forward to seeing many of my long list British colleagues!

YouTube video by Cool Worlds Podcast #23 Geraint Lewis - Fine-Tuning, Multiverse, Cosmological Tensions

Is the Universe finely-tuned for life? Geraint Lewis explains in our new Cool Worlds Podcast episode…

youtu.be/OejwZqh-F9U?...

This paper is hard to parse. I don’t recognize the institution and its full of grandiose claims “This is indeed a paradigm shift”. It also lacks a single figure or code. But if true, it would be v useful…. 🤔

arxiv.org/html/2506.18...

It arrived!

It happened again

arxiv.org/abs/2506.05392

Screenshot of the president's budget showing that the Exoplanet Exploration budget would reduce from $54.4M to $3.3M.

*speechless horror*

(Guys the NASA Exoplanet Archive is in this box. My job is in this box.)

Scientific Controversies: Aliens There may be more planets in the Milky Way galaxy than there are stars, some hundreds of billions. So where are all the aliens?We have sent landers to M...

Join me and @davidkipping.bsky.social tomorrow at @pioneerwork.bsky.social as we discuss... wait for it now... ALIENS.

Yeah, the real super-cool science of Life in the Universe kind of aliens. Not the endless stupid conspiracy theory stuff.

pioneerworks.org/programs/sci...

The Harvard visa ban is shooting ourselves in the foot. Harvard is a magnet of global talent. I was a predoc at Harvard & then a NASA Sagan fellow there before joining Columbia, so I am one of the many immigrants who was trained and drawn to the US by that incredible institution.

Oh I’d didn’t know that, good to know!

Insufficient evidence for DMS and DMDS in the atmosphere of K2-18 b. From a joint analysis of JWST NIRISS, NIRSpec, and MIRI observations Recent JWST observations of the temperate sub-Neptune K2-18 b have been interpreted as suggestive of a liquid water ocean with possible biological activity. Signatures of DMS and DMDS have been claime...

“we estimate that ~25 more MIRI transits would be needed for a 3-sigma rejection of a flat line relative to DMS/DMDS features” - wow, 25?!

arxiv.org/abs/2505.13407

The third SETI Symposium, presented by the Penn State Extraterrestrial Intelligence Center, will be hosted at the Penn Stater Hotel and Convention Center on August 18–21, 2025.

Abstracts for PSETI due May 31st - this is always a fascinating meeting!! #SETI

sites.psu.edu/setisymposiu...

Scientific Controversies: Aliens There may be more planets in the Milky Way galaxy than there are stars, some hundreds of billions. So where are all the aliens?We have sent landers to M...

Come join us at Pioneer Works next week for

Scientific Controversies: Aliens

Adam Frank and David Kipping in Conversation with Janna Levin

WEDNESDAY, MAY 28, 2025, 7:30PM

@davidkipping.bsky.social @jannalevin.bsky.social

pioneerworks.org/programs/sci...

Thanks! Just emailed you something I think you’ll appreciate…

By the way, you mentioned you advocate for subtracting one off the number of sigmas coming from Bayes factors - did you put that suggestion into a paper somewhere?