which pope ordered all church to keep an ever lighted lamp in it
which pope asked all catholic churches to keep a lighted lamp always in its altar
to show God was the Eternal light.
Many groups have eternal lamps. Zoroastrians maintain an eternal flame, doing everything they can to transmit that flame from lamp to lamp so that it preserves a continuous chain of combustion back to the dawn of that religion. The ancient Jewish Temple in Jerusalem had an eternal flame burning before the Holy of Holies. Today, Jews make a point of burning (or electrifying) an eternal lamp in front or above the ark where the Torah scrolls are kept in a synagogue, and Catholics have an altar lamp in front of the tabernacle where the sacraments are stored. The Cherokee Nation has preserved an eternal council fire, even carrying coals on the Trail of Tears to Oklahoma. Today, fires lit from those coals burn in both Cherokee, North Carolina and Talequah, Oklahoma. There are also many memorials around the world that include eternal flames.
It is not recommended to keep the lava lamp on for longer than 10 hours at a time.
The Torah-scroll, the prayerbooks; and many synagogues have an eternal lamp.
blanket and heat lamp (I recommend a blanket)
The ner tamid, or eternal light, is a reminder of the lamp in the Beis Hamikdash that never went out.
A ner tamid, also known as a sanctuary lamp, is "is a light that shines before the altar of sanctuaries in many denominations of Jewish" worship. "Hanging or standing in front of the ark in every Jewish synagogue, it is meant to represent the menorah of the Temple in Jerusalem as well as the continuously burning fire on the altar of burnt offerings in front of the Temple.[2] It also symbolizes God's eternal presence, and is therefore never extinguished." In the event of a power outage alternate energy sources keep the ner tamid lit.
A votive candle or votive lamp.
These holes, removes the hot air of lamp outside and receive cool air from the outer environment that maintains the lamp to cool.
The experts advise not to keep the lamp on for more than 10 hours. If you like to keep it on always, then turn it off after ten hours of starting it. Then wait till the lamp cools down and you can again start it for ten hours.
The Ner Tamid or Eternal Flame is a representation of the eternal flame that existed in the Great Temple in Jerusalem. In that Temple, there were flames on the sacrificial altar that were always burning. This constant light is a symbol of God's constant presence.