Short answer: it increases by a factor of 4. Here’s why (under the usual physics assumptions): So if the object shrinks to half it’s size: To keep constant: Angular momentum…
It is often stated that pulsar timings are very stable and hence used as a cosmic clock by astronomers. Yet, on a live demonstration at Dwingaloo Observatory in Netherlands tonight,…
There is no single officially published, modern value for the system temperature (Tsys) or SEFD of the 25 m Dwingeloo radio telescope that’s easy to point to. What follows is…
ezRA’s ezGLon.py program studies cross sections of the Milky Way, along one Galactic Longitude (GLon). ezRA’s ezGLon.py program processes *GLon.npz files. Above, the ezGLon.py program errored because it found *Gal.npz…
A half-wave dipole resonant at 1420 MHz (the hydrogen line) has essentially the same impedance as at any other frequency: In practice The actual feedpoint impedance will vary depending on…
What you’re seeing is real, and it surprises a lot of people the first time they map the Galaxy in the 21-cm line. In short: the Galactic centre is not…
Mostly from the optically dark regions between the spiral arms, not from the bright arms themselves. Here’s why that happens, and how it matches what you’re detecting. 1. What the…
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