In the Dark<p><strong>R.I.P. Jerry Ostriker (1937-2025)</strong></p> <p>Once again I find myself using this blog to pass on sad news. This time it is of the death of renowned astrophysicist <a href="https://en.wikipedia.org/wiki/Jeremiah_P._Ostriker" rel="nofollow noopener noreferrer" target="_blank">Jerry Ostriker</a> (pictured left in 2012), who passed away on Monday 6th April 2025 just a week before his 88th birthday.</p> <p>Jeremiah Paul Ostriker (to give his full name) was an extremely energetic, versatile and influential theorist who worked on a wide range of problems in diverse areas of astrophysics and produced a number of classic papers. Close to my own specialism I would quote two in particular: one written with Jim Peebles in 1973 <a href="https://ui.adsabs.harvard.edu/abs/1973ApJ...186..467O/abstract" rel="nofollow noopener noreferrer" target="_blank">about the stability of galactic disks</a>; and the other with Martin Rees in 1977 <a href="https://ui.adsabs.harvard.edu/abs/1977MNRAS.179..541R/abstract" rel="nofollow noopener noreferrer" target="_blank">about the role of gas cooling and fragmentation in determining the size of galaxies and clusters</a>. He also did much to establish the use of hydrodynamic simulations in cosmology and was an early adopter of the current standard cosmological model, including a cosmological constant. He worked on many other things too, including pulsars and galactic nuclei.</p><p>I only met Jerry Ostriker a few times, mainly at conferences – where he was never shy to contribute to discussions after talks – but also once back in the 1990s when I was a visitor Princeton (where he was Professor). I didn’t have much time to talk to him then as he always seemed to be on the go, so I never really got to know him personally. After spending most of his career in Princeton, including a spell as Provost, in 2001 Ostriker moved to Cambridge for a short stint as <a href="https://en.wikipedia.org/wiki/Plumian_Professor_of_Astronomy_and_Experimental_Philosophy" rel="nofollow noopener noreferrer" target="_blank">Plumian Professor</a>, before returning to Princeton.</p><p>There is <a href="https://www.nytimes.com/2025/04/07/science/space/jeremiah-ostriker-dead.html" rel="nofollow noopener noreferrer" target="_blank">a very nice obituary</a> of Jerry Ostriker by Dennis Overbye in the New York Times.</p><p>Rest in peace, Jerry Ostriker</p><p><a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://telescoper.blog/tag/astrophysics/" target="_blank">#Astrophysics</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://telescoper.blog/tag/cosmology/" target="_blank">#Cosmology</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://telescoper.blog/tag/galaxy-formation/" target="_blank">#galaxyFormation</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://telescoper.blog/tag/jeremiah-p-ostriker/" target="_blank">#JeremiahPOstriker</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://telescoper.blog/tag/jerry-ostriker/" target="_blank">#JerryOstriker</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://telescoper.blog/tag/princeton/" target="_blank">#Princeton</a></p>