Surveying dark energy across the universe - with Ofer Lahav

Join world-leading scientist Ofer Lahav as he reveals the narrative of the Dark Energy Survey (DES), an ambitious experiment designed to unravel the mysteries of the force shaping our universe.
Watch the Q&A here (exclusively for our Science Supporters):
Discover what the 3D map spanning 300 million galaxies and extensive supernovae has so far revealed, including its confirmation of the prevailing model of cold dark matter and a remarkably accurate cosmological constant.
But this remarkable survey doesn’t just advance our scientific understanding - Ofer sheds light on the human dimension of this project, sharing anecdotes of the long-term commitment and collaboration of the hundreds of scientists involved and the resilience they’ve shown in overcoming challenges along the way.
Join Ofer to explore the global nature of scientific progress, where teamwork and perseverance shape groundbreaking discoveries. The DES not only helps to reveal the mysteries of dark energy but also highlights the collective dedication and collaborative spirit that fuels scientific exploration.
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Ofer Lahav holds the Perren Chair of Astronomy at University College London (UCL) and is Vice-Dean (International) of the UCL Faculty of Mathematical and Physical Sciences (MAPS). Additionally, he co-directs the STFC Centre for Doctoral Training in Data Intensive Science. Specialising in Observational Cosmology, Lahav focuses on probing Dark Matter and Dark Energy, utilising Machine Learning for Big Data applications. Having served as the Head of Astrophysics at UCL from 2004 to 2011 and as Vice-Dean (Research) of UCL's Faculty of Mathematical and Physical Sciences from 2011 to 2015, Oher has played key roles in academic leadership. He served as Vice-President of the Royal Astronomical Society from 2010 to 2012 and played a pivotal role in founding the Dark Energy Survey (DES). His multi-faceted roles and groundbreaking research highlight his commitment to advancing the field of observational cosmology and understanding the fundamental properties of the universe.
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[@user-to9ge8ii9n]

They should just spend five bucks and read the comments on this video, I'm sure they've found the solution. /sarcasm

[@a12i9]

love this topic, it's just fascinating how much we don't see!

[@ytb40]

It is also fascinating that people will never see or be able to get a glimpse on dark energy, because it does not exist.

[@i_booba]

@@ytb40dark energy is the placeholder name we have for what’s causing the accelerated expansion of the universe. The simplest explanation is it’s a constant energy density corresponding to the vacuum of empty space. This is quite an ordinary concept in quantum physics - the zero point energy. The details elude us; that doesn’t mean it “doesn’t exist.” How about this - let scientists who have been studying this phenomenon since 1998 keep studying it, and maybe one day we can figure out those missing details?

[@isatousarr7044]

The study of dark energy is crucial for understanding the accelerated expansion of the universe. As we develop more advanced observational tools and methodologies, our ability to survey and map dark energy improves significantly. This could offer profound insights into the fundamental forces shaping the cosmos. Given the challenges and complexities involved in observing and analyzing dark energy, what are the latest advancements in technology or methods that are enhancing our ability to survey it? How might these improvements impact our understanding of the universe's expansion and the nature of dark energy itself?

[@ytb40]

It's more interesting to study the traits of fairies in the Grimm's Storybook. Like dark energy, they also do not exist in reality, but they are much more beautiful.

[@GordonShuffell]

The oft used discription of universe as currents moving away from each other in a baking cake is ok . but I like the idea that the oven it's baking in could be a black hole

[@SiqueScarface]

11:45 I know why I don't like raisins.

[@Usrnet]

The galaxy’s rotation curves seem to result from them masses being tied but not a curved space all the way around the galaxies as spheres.

[@terrycook2733]

Quark wormholes are a good topic

[@edstauffer426]

Redshift = redshift +- the difference between the measured gravity well and the measuring gravity well. Almost everything is in a deeper gravity well and light redshifts as it climbs out of a gravity well.

[@Trystan3345]

Clown 🤡

[@daddust]

It took me a decade to understand why we can use stars as standardized candles. It wasn’t in the text books or in videos I watched. It wasn’t explained here either unfortunately. Candles aren’t a good explanation, I wondered why a dimmer star wasn’t just one that was smaller, not necessarily further away.

[@saltynutzz]

Because when you actually get into wavelengths of light you can tell by how red-shifted it is, and than tell how far away it is so you know if it's a smaller dinner star closer or a bigger star that's far away. There's also the Doppler effect of the light as well which tells you which direction the star is spinning.

[@tobysemler]

You wouldn't have to rush the actual topic if you didn't spend 45 minutes rehashing popular physics we've all heard 20 times.

[@Dowskiify]

For those too lazy to watch: The survey clearly indicates that dark energy is somewhat disappointed by our understanding of it. There's some resentment about being called "something" or "unexplainable " and the respondent insisted they were more than "just a mistake by a guy named Einstein". All in all dark energy feels misunderstood, misrepresented and therefore underappreciated. We need to do better people!

[@Hooves1]

only JWST is more exciting

[@kellyandthehorses2877]

Is space time dark energy?

[@kx4532]

The surveyed it! 🎉🎉🎉🎉🎉

[@q4077]

All we know for sure is it tastes like chicken

[@DanielMasmanian]

"and the results of the survey are in, but just need another trillion dollars to count them"

[@AndersJB-se8ff]

Its a Gravity field

[@Returntotruereality]

One night i saw the sky open and i can only describe what i saw was a lazer like beam of dark energy that hit me. Since then my way of thinking has changed and much more. I left my body when the dark energy hit. Believe it or not, im trying to write down the understandings i have received since. Knowledge is a word i have written about alot. What we think to be true does not mean that it is true. The Truth is out there.

[@Joe_Mama869]

Consult your doctor if hallucinations occur for more than 4 hours

[@Returntotruereality]

@@Joe_Mama869 I always lie

[@Returntotruereality]

What I said can only be believed. That does not mean that it is not true. I know what I saw and I remember what I experienced. You were not there, so you did not see what I saw so you do not know what I saw and you are saying what you think to be true without knowing the truth.

[@Joe_Mama869]

@Createanewreality it can also not be believed. If it's not verifiable, then it doesn't belong here. Maybe try truth social, lol.

[@Joe_Mama869]

@@Returntotruereality I can tell. So can the rest of the internet

[@jimdenzler389]

Dark energy… matters! So does consciousness… (The Bad Luck Tree)

[@DavidHall-x1u]

They're not like us👁️

[@shawns0762]

There is only one reason to postulate dark energy, to explain the exponential expansion rate of the universe. The expansion was discovered in 1929. In 1998 it was discovered that the expansion is accelerating, this is when the concept of dark energy became mainstream. If something accelerates at a constant rate it will get faster and faster. If a spaceship travels at a constant 1g acceleration rate it would achieve about 95% light speed in 1 year. Electricity is drawn towards potential and the universe as a whole behaves the same way. Electricity comes into our homes because the neutral circuit provides the potential. Physicists in the last century did not postulate dark energy because they understood that the expansion is a fundamental property of the universe. The fact that the expansion is accelerating does not invalidate their reasoning, it's what the known laws of physics would predict provided gravitational forces are not strong enough to counteract the process. All studies to find dark energy have been fruitless because it doesn't exist. To say there is dark energy is to say there is 5 fundamental forces, there is 4

[@Joe_Mama869]

If you understand what fundamental means, then please explain which potential quantum field the expansion(/ or inflation) of the universe resides with. Thx

[@shawns0762]

@@Joe_Mama869 The universe is expanding towards potential, there is no reason to postulate a quantum field to explain this. Einstein, Planck, Heisenberg, Schrodinger, Dirac, Pauli, Feynman and almost every other physicist in the last century did not postulate dark energy for this reason.

[@Joe_Mama869]

@shawns0762 do... do you even understand the forces then..? And the existence of 4 forces does not mean 5 cannot exsist.exist. not to mention the universe is expanding BECAUSE of potential. Not toward it. Entropy dictates that you are an idiot and have no clue what you're talking about

[@chrwi5848]

Carl Sagan has never said "billions and billions".

[@Neilhuny]

He also didn't say he was a Christmas tree. So what? Billions and billions is perfectly acceptable in this context

[@blockblock7845]

​@@Neilhuny obviously wasn't saying anything about the context. Merely the fact that Carl Sagan never actually said the quote.

[@tormodguldvog8405]

In Chapter 1 in his book «Cosmos» he wrote «A galaxy consists of gas, dust and stars - billions and billions of stars.» (Translated from the Norwegian edition).

[@harveytheparaglidingchaser7039]

From Wikipedia "Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium is a 1997 book by the American astronomer and science popularizer Carl Sagan. The last book written by Sagan before his death in 1996,[1] it was published by Random House."

[@timothy8426]

I'm going with centrifugal force of magnetism bonding and repulsion within occupational space as mass. Magnets show the bonding force of centrifugal force spinning all external heat energy currents grounding back onto itself cycling circulation through its nucleus or core like earth's quantumized internal magnetic fields of elementary accumulation of mass as heat grounding currents into itself as mass. Mass neutralizes cold repulsion of occupational space within mass as outward force of pressure known as impaction when resistance can't be overcome. The greater the mass, the greater the force of pressure and repulsion to it. Greater mass has farther reaching magnetic fields grounding currents through all masses in its path. So mass falls in equalization to magnetism repulsion. Magnetic fields of heavier objects are further outward repulsion than lighter elements. Do the math. Centrifugal force of external magnetic fields spinning all external heat energy outside of the nucleus or core like a record on a record player centrifugal force flowing around these massive external magnetic fields. Distance traveling is always equal to the force of pressure. Magnetism explains everything about physics without gravity and bending space and electricity. Heat grounding currents through all masses in its path until resistance can't be overcome and impaction force is current grounding. You walk in a stream and feel the force of currents flowing. You step into a fast-moving river, and you are pulled away into the flow. Heat grounding currents through centrifugal forces of magnetism flowing currents works the same. External heat energy outside of entanglement of mass doesn't ground energy. Fire is an external magnetic field. The closer to the core, the minimum distance and force increase. Walk away from the core distance, traveling increases, and force decreases as magnetism. Appliances catch fire. Lightning is rapid heat loss instantaneously fire lighting up the atmosphere like filaments. Campfires are slowly disolving internal magnetic fields of internal magnetic fields of mass as potential renewable heat energy when absorbed into internal magnetic fields grounding currents through its nucleus or core. Mass is quantumized internal magnetic fields of centrifugal force. Heat and cold space coexist as anti-matter as cold repulsion to heat energy singularities propulsion momentum from cold repulsion perpetual motion momentum as maximum distance traveling and minimum force of pressure to and from as space is a weak external magnetic field. Hydrogen is the cosmic speed limit in cold repulsion of normal momentum of space itself. Space is filled with dark heat energy, with the exception of external magnetic fields spinning outside of monopoles of pure fabric of cold space with absolute zero heat energy within its core or nucleus as external magnetic fields spinning centrifugal forces flowing around these massive external magnetic fields spinning all external heat energy within its field in equalization to magnetism. Neutralized occupational space of repulsion allows faster heat energy propulsion centrifugal force cycling circulation faster than normal momentum of space. The immediate accretion disk surrounding the event horizon perimeter spinning heat faster than normal momentum of space in neutralized repulsion of space as occupational heat cycling circulation around these monopoles of pure repulsion to heat propulsion faster velocity. Hydrogen is the most abundant element because it exceeds the normal momentum of space itself. When heat hits cold repulsion of normal cold repulsion redirecting heat energy trajectories backwards onto itself as centrifugal force as hydrogen as internal magnetic fields grounding currents through its nucleus or core where external heat energy force is strongest.

[@walter6574]

dark energy does not exist. The issue is astrophysicists don't know why the universe is expanding. I am currently exploring what is causing the universe to expand. I am not ready to propose my hypothesis as data necessary is not readily available.

[@karlbarlow8040]

Dark energy is the only thing that exists. Everything else is just aspects of it.

[@kzeich]

Jeff from Curb Your Enthusiasm moonlights as a astrophysicist

[@stevenkirkwood7039]

If you’re only at the hypothesis step of the scientific method, you’ve yet to prove your own hypothesis. Claiming that any other hypothesis, theory or law is incorrect when your hypothesis still remains unproven and untested (or at the very least, unreported) is showing ignorance of how science and peer review works.

[@walter6574]

@@stevenkirkwood7039 correct, yet dark energy and dark matter are only hypothesis.

[@C-ManFromGer]

Well. You might be a genius going to get a Nobel Prize OR just some maniac shouting out weird things into the internet that will forever only make sense to you. Won't judge here but without any credidble thesis the Nobel Prize is not going to happen soon.

[@Hank-x5q]

Utterly useless presentation. "You're Not Like Us."

[@Neilhuny]

Eh?

[@Hank-x5q]

@@Neilhuny When is mass no longer mass?

[@Neilhuny]

@@Hank-x5q When a Protestant minister takes the service?

[@bogdy72000]

poppycok