Geraint F. Lewis @Cosmic_Horizons Twitter profile

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Omg!!!! I just made a wormhole!

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Your physics reminder that stripes in a polarizer do not let orientations of the electric field slide through like letters in a postbox. In fact it's the opposite (Wikipedia has it correct)

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Geraint F. Lewis

@Cosmic_Horizons

2 years

A Friday reminder that Hertz was not looking to find new methods of communication when he discovered radio waves. He was just intrigued by the consequences of Maxwell's equations. Blue sky science is a good thing. It can be risky, but the payoffs can be huge.

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Geraint F. Lewis

@Cosmic_Horizons

7 months

A lone neutron will decay in about 15 mins, but a neutron inside an atomic nucleus doesn’t (generally) decay. One of the reasons is that about 10^22 times per second, each neutron switches identity with a proton and then back again. Image from hyperphysics

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Geraint F. Lewis

@Cosmic_Horizons

9 months

Relativistic cake after my Hobart talk!!

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Geraint F. Lewis

@Cosmic_Horizons

1 year

It's that of year where I, depending on your view, teach some wonderful physics or brainwash the youngsters to shield them from the "truth".

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Geraint F. Lewis

@Cosmic_Horizons

4 years

James Clerk Maxwell was clearly a night owl

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Geraint F. Lewis

@Cosmic_Horizons

2 years

This is from Penrose in the 1970s - Is it me, or is there a bit of a double meaning here?

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Geraint F. Lewis

@Cosmic_Horizons

3 months

Hi @WalesOnline @NPTCGroup @michaelsheen - could we get a retweet for my lecture? Bringing cosmology to Pontypridd!

valleyboyo

@Zeumbaalflredo

3 months

Great science talk on the Big Bang to be given by Wales's leading physicist @Cosmic_Horizons , free to school students on August 2nd 7pm @UniSouthWales , see , check it out @DT_Glantaf , @phstd @PontypriddHS @6edPlasmawr @macs_science @aths_science

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Geraint F. Lewis

@Cosmic_Horizons

2 years

@toxvaerd1 It's the Lagrangian for electromagnetism

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Geraint F. Lewis

@Cosmic_Horizons

3 years

The happiest line in any physics paper.

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Stephen Hawking on time travel.

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Geraint F. Lewis

@Cosmic_Horizons

3 years

From "Quantum field theory for the gifted amateur" by Lancaster and Blundell

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Geraint F. Lewis

@Cosmic_Horizons

4 years

A little while ago, I consulted on a video by @veritasium (& @SciencePetr ) in the fact that you cannot measure the one-way speed of light. So many people said “obviously the speed of light is the same in all direction….

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Geraint F. Lewis

@Cosmic_Horizons

6 years

Ping @tanya_plibersek - I have an idea! Give teachers the MP wage and perks, and the brightest will be fighting to get in - and give MPs a teacher's wage, so that only those that truly care join parliament.

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Geraint F. Lewis

@Cosmic_Horizons

2 years

@NoContextBrits Broken

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Geraint F. Lewis

@Cosmic_Horizons

9 months

Spotted on today's arxiv...

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Not now, Microsoft Word….

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Geraint F. Lewis

@Cosmic_Horizons

2 years

So glad my little question about electricity is still generating content on YouTube (this time by @ElectroBOOMGuy - ) and that I was still correct :)

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Geraint F. Lewis

@Cosmic_Horizons

5 years

@gleet_tweet Luckily women is one homogenous group and I can confidently claim that all men love physics (except for the ones that don’t)

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Geraint F. Lewis

@Cosmic_Horizons

2 years

What's it like to orbit a black hole? Here's a frame from a new movie that I'm making to be viewed in VR and which accurately calculates photon paths and orbits in a Schwarzschild spacetime.

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Geraint F. Lewis

@Cosmic_Horizons

4 years

With The Queen’s Gambit on @netflix , thanks to @nosuchthing for highlighting this quote by Grandmaster Judit Polgar on her Grandmaster sister Susan.

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Very proud to have been awarded the Physics Communication Award by the @ausphysicsTPG

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Remember, physics is not maths, and maths is not physics.

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Geraint F. Lewis

@Cosmic_Horizons

1 year

Still freaks me out a little that 1 km/s ~ 1 kpc/Gyr to within a couple of percent.

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Geraint F. Lewis

@Cosmic_Horizons

3 years

I wonder how many people would be shocked to learn that most astronomers don’t actually care about Pluto and which box it is put in….

NYT Science

@NYTScience

3 years

Can we resolve this debate once and for all?

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Geraint F. Lewis

@Cosmic_Horizons

3 years

A small trumpet blow - I’ve been awarded the 2021 Pollock Memorial Lectureship of the Royal Society of NSW. I’m rather humbled to join this list of outstanding recipients. #Physics #DarkMatter #darkenergy

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Geraint F. Lewis

@Cosmic_Horizons

5 years

Important words for science students from Zach Weinersmith.

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Your Friday reminder that the term “Ultraviolet Catastrophe” was coined in 1911, the R-J approximation was found in 1905, and Planck derived the Blackbody spectrum in 1900. No matter what your physics textbook says, Planck was not inspired by the ultraviolet catastrophe.

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Geraint F. Lewis

@Cosmic_Horizons

4 years

Delayed by Christmas, but the paper on the One Way Speed of Light in cosmology is now on the @arxiv (ping @veritasium and @SciencePetr )

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Geraint F. Lewis

@Cosmic_Horizons

2 years

The titles Prince and Princess of Wales is a continued 700 year old slap in the face from the royal family.

Owen Williams 🏴󠁧󠁢󠁷󠁬󠁳󠁿

@OwsWills

2 years

“It’s worth reminding ourselves how horribly divisive Charles’ investiture was. Large parts of Wales considered the investiture an insult – their subjugation rubbed in their faces” ✍️ ⁦ @ifanmj ⁩

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Geraint F. Lewis

@Cosmic_Horizons

1 year

Fantastic demonstration of what components dominated at different epochs in the universe. From:

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Fellow scientists - did we really say this? Had we been in the pub?

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Geraint F. Lewis

@Cosmic_Horizons

2 years

It's the 1st August and a new semester at the University of Sydney. Tomorrow is my first lecture in General Relativity and Cosmology, so a short thread on rotating black holes and a sad anniversary. 1/n

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Colleagues inc. Rodrigo Ibata, @kmalhan07 and @nfmartin1980 published the lovely StreamFinder catalog of the galactic halo. It’s great to see the real halo look like the simulations I’ve seem for decades. I was so happy, I made a little video :)

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Geraint F. Lewis

@Cosmic_Horizons

2 years

@Researchfish @bedcatalysis @seis_matters Wow! I will be keeping this to use if you ever come knocking at my university or funding agency's door.

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Geraint F. Lewis

@Cosmic_Horizons

3 years

I have a feeling that there is going to be a lot of discussion of this paper on the arxiv today….

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Geraint F. Lewis

@Cosmic_Horizons

7 years

Word, please stop changing “most dark matter” to “darkest matter”. I’ve got a grant to write!

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Geraint F. Lewis

@Cosmic_Horizons

10 months

Hello darkness, my old friend...

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Geraint F. Lewis

@Cosmic_Horizons

2 years

My final contribution to #piday - The accuracy for fractional approximations to pi.

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Geraint F. Lewis

@Cosmic_Horizons

1 year

It took a month to generate, but please enjoy this high resolution microlensing magnification map.

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Geraint F. Lewis

@Cosmic_Horizons

5 years

For the heck of it, here’s the world map with Australia at the North Pole. Distortion much?

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Geraint F. Lewis

@Cosmic_Horizons

4 years

Yesterday I received @Sydney_Uni Vice Chancellor’s Award for Outstanding Research, although I didn’t make it to the Zoom screen :( I put a shirt on and everything! @sifa_astro

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Geraint F. Lewis

@Cosmic_Horizons

2 years

@muunsparks But it wasn’t a wormhole - it was a physical process whose maths map onto those of a wormhole. In the same way that a current in a circuit can be represented as a hydrodynamic situation, it does not mean that the current is actually water.

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Geraint F. Lewis

@Cosmic_Horizons

4 years

Big day - my PhD student, Zhen Wan’s paper “The Tidal Remnant of a Metal-Poor Globular Cluster” appeared in Nature A big team effort with @sazabi_li @FadAstra @_sarahmartell_ @deniserkal @dougalmackey @alexanderpji @kwkuehn @norashipp @balbinotdd @JossBlandHawtho & more

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Geraint F. Lewis

@Cosmic_Horizons

4 years

The media’s breathless reporting ( == straw grabbing ) of the smallest announcement of COVID vaccine research is further evidence that a little more science education for journos would not hurt.

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Geraint F. Lewis

@Cosmic_Horizons

5 years

I chatted with @veritasium about black holes and “shadows” this week - here’s his excellent video on the topic!

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Geraint F. Lewis

@Cosmic_Horizons

4 years

Some thoughts and comments about outreach in physics. We will get to some astro, I promise I will get to astronomy eventually. Let’s start with a question - “Why is the sky blue?"

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Your Sunday reminder that photons are not fired off randomly into space. The emitter and detector agree through transactions back and forth in space and time to exchange a photon. This means …

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Geraint F. Lewis

@Cosmic_Horizons

1 year

Now that's a big hole in the ground!

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Geraint F. Lewis

@Cosmic_Horizons

2 months

Galileo lived at number 42! Coincidence???

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Geraint F. Lewis

@Cosmic_Horizons

2 years

@NuclearSharpe @lukebarnesastro And ps - this paper has the *best* acknowledgements!

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Geraint F. Lewis

@Cosmic_Horizons

2 years

You appear in one @veritasium video discussing dark matter, and the email start to arrive…..

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Geraint F. Lewis

@Cosmic_Horizons

4 years

Science is 1% inspiration 5% perspiration 108% fiddling with tickmarks in matplotlib

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Geraint F. Lewis

@Cosmic_Horizons

8 months

The Lagrange points are not points where the gravitational forces of the bodies balance. They are points where the bodies provide the centripetal acceleration such that the orbital period is the same of the lower mass body.

Physics In History

@PhysInHistory

8 months

Lagrange points are positions in space where the gravitational forces of two large masses, such as the Sun and the Earth, balance each other out. This means that a small object, such as a satellite, can orbit at these points with minimal fuel consumption. There are five Lagrange

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Geraint F. Lewis

@Cosmic_Horizons

1 year

@rgpoulussen That's not a V-vor-Victory - it's just the Vicks, meaning "f*ck off".

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Big paper day today! The discovery of a dark stream, the Dulais Structure in the Andromeda Galaxy.

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Geraint F. Lewis

@Cosmic_Horizons

1 year

Ah, you've gotta love waking up and reading messages from your adoring fans!

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Check out the new @veritasium video on how energy flows in electrical circuits. All kicked off by my emailed puzzle below (ping @DoctorKarl )

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Geraint F. Lewis

@Cosmic_Horizons

7 years

“Top marks for a paper title” goes to

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Geraint F. Lewis

@Cosmic_Horizons

1 year

Today I walked in 120 million year old footsteps....

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Lots of talk about high redshift galaxies and JWST - but it's important to remember that redshift and time are nonlinear and more than half the time of the universe is below redshift 1, and only 3% greater than 10. Each chunk of redshift is a smaller slice of time.

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Today in cutting-edge research....

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Geraint F. Lewis

@Cosmic_Horizons

1 year

Non-physics - but my homeland is a beautiful country

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Hello darkness my old friend...

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Freshly minted Dr Oliver and Dr Hossen

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Geraint F. Lewis

@Cosmic_Horizons

6 years

Thursday morning mini-rant coming…. I’ve been stewing over this “galaxy with no dark matter” for a couple of days. The data is sparse and noisy, and the conclusions sensational. But the battleground is statistics - how do you compare data with theory...

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Geraint F. Lewis

@Cosmic_Horizons

10 months

When your science becomes literal art!

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Geraint F. Lewis

@Cosmic_Horizons

8 months

Paper two: The Dark Energy Survey: Cosmology Results With ~1500 New High-redshift Type Ia Supernovae Using The Full 5-year Dataset by the DES Collaboration.

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Your 2022 reminder that the closest planet to the Earth (on average) is Mercury. Fun fact, Mercury is, on average, the closest planet to any planet in the Solar System.

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Great fun talking about "Adventures in the Dark-Side of the Universe" at #ASAASM2022 last night - great questions about what we hope to find about dark matter and dark energy. And thanks for awarding my @AstroSocAus David Allen Prize in person!

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Geraint F. Lewis

@Cosmic_Horizons

3 years

So, @veritasium ’s new video is so good, I’ve added a new slide to my upcoming lectures on “Oscillations, Chaos and Waves”.

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Geraint F. Lewis

@Cosmic_Horizons

10 months

Well, here is some rubbish science. Everything is stationary in its own rest frame. That is the entire point of relativity and this nonsense - which suggests there is an absolute frame in the universe - is profoundly non-relativistic. Please make it stop....

StarTalk

@StarTalkRadio

10 months

Is there anything in the universe that is absolutely stationary? 🤔

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Just arrived in the mail! - really looking forward to reading @csferrie new exploration of how to ruin my life with advice from quantum physics.

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Geraint F. Lewis

@Cosmic_Horizons

3 years

@toomanyspectra Gravitational Microlensing

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Geraint F. Lewis

@Cosmic_Horizons

4 years

Groan - @LisaMillar called those interest in science “geeks” on @BreakfastNews - I hate this aspect of #ScienceWeek - How about a bit of respect for science? Like the same worshiping the news gives to sport?

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Geraint F. Lewis

@Cosmic_Horizons

3 years

For everyone complaining about observing with the lights turned on in the dome in Don’t Look Up, of course, no serious astronomer would be caught dead in the dome looking through a telescope with the lights on (and with a pipe in their mouth).

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Very honoured to receive the Pollock Memorial Lectureship for my work on the dark universe from the @royalsocnsw at Government House last night. Felt strange dressing up for the evening 😀 (ping @sifa_astro )

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Backyard is looking lovely today

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Geraint F. Lewis

@Cosmic_Horizons

4 years

One of the most dangerous science myths is that Einstein was an “amateur”. Whilst he did not hold an academic position in 1900, he did have an education in advanced physics and mathematics, and had published 5 papers before his “miraculous year”. His 1905 papers ...

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Lots of people seem unaware that Olivia Newton John's grandfather was Nobel Prize winner Max Born. They are going to freak out when they learn who the father of the lead singer of the Eels was!

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Geraint F. Lewis

@Cosmic_Horizons

3 years

Where did the matter in the universe come from? This is the topic of a new blog post - “On the matter of matter”. #science #cosmology

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Geraint F. Lewis

@Cosmic_Horizons

4 years

This paper is not beating about the bush…

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Geraint F. Lewis

@Cosmic_Horizons

2 years

@NoContextBrits It's going to be gone soon.

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Geraint F. Lewis

@Cosmic_Horizons

10 months

On the 50th birthday of the Opera House, it's worth remembering that it has been 20 years since fellow astronomer Will Saunders (with Dave Burgess) painted No War on it. Perhaps the message should have been left there.

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Geraint F. Lewis

@Cosmic_Horizons

3 years

What is and isn’t science? String theory? The Multiverse? I tackle this question in my new blog post - “Science and the Laconic If” #science #cosmology

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Geraint F. Lewis

@Cosmic_Horizons

6 years

Dear retired engineers (invariably male), I am happy to chat with you about your alternative cosmological theories, even though you haven't worked out the maths, after my talks, but please let other people, especially kids, get a word in now and again!

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Watched "Everything Everywhere All At Once" - a strange but enjoyable film that gets the fine-tuning argument across the multiverse right!

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Geraint F. Lewis

@Cosmic_Horizons

5 years

The salubrious life of the astronomer. 16 hour shifts in a windowless room.

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Geraint F. Lewis

@Cosmic_Horizons

6 years

Hey @netflix , I unfortunately sat through “Io" last night and need to remind you that astronomers don’t have the lights on in the dome when they are observing with a telescope. Feel free to ask us about this, we’re friendly people.

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Geraint F. Lewis

@Cosmic_Horizons

1 year

Oh, I see the old “you work X hours in astronomy, well I work Y hours… you slacker” debate is back on twitter. Let me add to this debate by saying that the hours I work is none of your business and your hours do not impress me.

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Great to make the news in my homeland!

Team led by Welsh scientists makes intergalactic cannibalism breakthrough

An international team of scientists led by an astrophysicist from Wales has shed new light on the life of galaxies and how they grow. The team, led by Professor Geraint Lewis from the University of...

nation.cymru

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Geraint F. Lewis

@Cosmic_Horizons

2 years

Small bit of Thursday fun - We all know that a proton has a mass of 931.494 MeV and contains three quarks - two up and a down.