Talk:Picometre

Isn't the diameter of the hydrogen atom ca. 50 pm?

i.e. less than the quoted minimum of 62 pm (for He). — Preceding unsigned comment added by 2.97.127.212 (talk) 19:10, 7 March 2017 (UTC)

Picture

Is the helium picture the Van der Waals radius? It's not clear.

It appears to be the calculated atomic radius. See http://en.wikipedia.org/wiki/Atomic_radii_of_the_elements_%28data_page%29. NRLer 14:37, 26 October 2007 (UTC)

µµ = nanometre

In the articles

• THE SVEDBERG and J. BURTON NICHOLS; “Determination of the size and distribution of size of particle by centrifugal methods”; Journal of the American Chemical Society; American Chemical Society, Washington, D.C.; December 1923; 45 (12): pp. 2910–2917.

• THE SVEDBERG and HERMAN RINDE; “The ulta-centrifuge, a new instrument for the determination of size and distribution of size of particle in amicroscopic colloids”; Journal of the American Chemical Society; American Chemical Society, Washington, D.C.; December 1924; 46 (12): pp. 2677–2693.

µµ is evidently used to mean what is now written as nanometre. —DIV (128.250.80.15 (talk) 00:55, 6 June 2008 (UTC))

Size of Helium Atom

The label of the diagram of the Helium atom specifies that the radius is 31 pm but according to this paragraph Atom in the Size section, it is written that the smallest atom is of Helium which has a radius of 32 pm. Either of the one article needs to be corrected! —Preceding unsigned comment added by Ammubhave (talk • contribs) 13:33, 7 April 2010 (UTC)

Currently, as of 10.12.2012, the 2nd paragraph states that atoms have a lower-bound radius of 62 pm, one half the radius of the Helium atom (31 pm) attested in the caption of the associated graphic. There is likely some good explanation for this, but it needs to be supplied. Otherwise, the reader is given conflicting information concerning the size of small atoms. — Preceding unsigned comment added by 2607:F140:400:2140:21B:63FF:FEC2:E0AB (talk) 18:57, 10 December 2012 (UTC)

I'm no physicist, but isn't Hydrogen the smallest element? It has one electron and one proton, half the mass of helium. I'm too lazy to look this up 98.164.93.8 (talk) 21:48, 31 March 2011 (UTC)

Yes, but we're making no claims that the helium atom is the smallest here. --Yoderj (talk) 14:29, 27 October 2012 (UTC)

LISA seems irrelevent

The following paragraph does not seem to belong here:

The Laser Interferometer Space Antenna (LISA) probe had been planned to be launched in 2025 to directly detect gravitational waves and would have been able to measure relative displacements with a resolution of 20 picometres over a distance of 5 million kilometres, yielding a strain sensitivity of better than 1 part in 1020. 2011 mission changes have put the fate of the LISA project in jeopardy.

Can I just delete it? --Yoderj (talk) 14:17, 27 October 2012 (UTC)

Unit Conversion : wrong

In the box at the right is wrote:

Natural units	   6.1877×10^ 221 ℓP

Please could someone rectify this measure ? — Preceding unsigned comment added by Windino (talk • contribs) 15:13, 11 September 2016 (UTC)