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Our Expert Voices conversation on space.

You may have heard that space is expanding, or that the fabric of space-time ripples quite literally like a wave. These are absolutely true – and awesome – statements, but what do they imply about the nature of space?

Concepts like expanding space or gravitational waves often lead people to think of space as having existence in and of itself. But space has no meaning without distinct objects; a truly empty universe is no universe at all. One might object that in a vacuum, virtual particles pop into and out of existence – but then such a universe isn't really empty, is it?

The expansion of the Universe, gravitational waves, and other phenomena are the function of physical objects acting according to physical laws; they do not necessitate that space itself physically exists. Until a future theory of quantum gravity weighs in on the issue, there is no reason to think of space as a thing.

Bottom line: Space is not a thing. Space is merely the only way to conceptualize the existence of distinct things in the Universe, just as time is the only way to conceptualize a Universe in which things change.

Other voices in the conversation:

Sean Carroll, theoretical physicist, California Institute of Technology: Space is overrated

Izabella Laba, mathematician, University of British Columbia: We can work with space without understanding its essence

David Albert, philosopher, Columbia University: Maybe there is no space

Go deeper

Updated 1 hour ago - World

U.S. releases report finding Saudi prince approved Khashoggi operation

Photo: Bandar Algaloud / Saudi Kingdom Council / Handout/Anadolu Agency via Getty Images

The Office of the Director of National Intelligence (ODNI) has released an unclassified report assessing that Saudi Crown Prince Mohammed bin Salman (MBS) approved the operation to "capture or kill" Washington Post journalist Jamal Khashoggi in 2018.

Driving the news: The White House also announced sanctions on entities implicated in the murder, though not on MBS directly. Officials also announced a new "Khashoggi ban" under which individuals accused of harassing journalists or dissidents outside their borders can be barred from entering the U.S.

About 20% of U.S. adults have received first vaccine dose, White House says

Joe Biden speaks during an event commemorating the 50 million COVID-19 vaccine shots. Photo: Doug Mills-Pool/Getty Images

Nearly 1 in 5 adults and nearly half of Americans 65 and older have received their first dose of the coronavirus vaccine, White House senior adviser Andy Slavitt said on Friday.

The big picture: The Biden administration has previously said it has secured enough doses to vaccinate most of the American population by the end of July.

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Health: Most COVID-19 survivors can weather risk of reinfection, study says — "Twindemic" averted as flu reports plummet amid coronavirus crisis
  2. Vaccine: Employers mull COVID vaccine requirements — New data reignites the debate over coronavirus vaccine strategyPfizer begins study on 3rd vaccine dose as booster shot against new strains.
  3. Economy: What's really going on with the labor market.
  4. Local: All adult Minnesotans will likely be eligible for COVID-19 vaccine by summer — Another wealthy Florida community receives special access to COVID-19 vaccine.
  5. Sports: Poll weighs impact of athlete vaccination.