NASAのインスタグラム(nasagoddard) - 8月14日 23時36分

Hubble Revisits a Globular Cluster’s Age -- Globular clusters are big balls of old stars that orbit around their host galaxy. It has long been believed that all the stars within a globular cluster form at the about same time, a property which can be used to determine the cluster's age. For more massive globulars however, detailed observations have shown that this is not entirely true — there is evidence that they instead consist of multiple populations of stars born at different times. One of the driving forces behind this behavior is thought to be gravity: more massive globulars manage to grab more gas and dust, which can then be transformed into new stars.

Credit: ESA and NASA #nasagoddard #hubble #space #star #galaxy

[BIHAKUEN]UVシールド(UVShield)

>> 飲む日焼け止め！「UVシールド」を購入する