This animation depicts a pulsar, approximately 20 kilometres in diameter, accreting material from a companion star. The strong gravity from the dense pulsar attracts material from the companion. The flow of gas from the companion to the pulsar is energetic and glows in X-ray light. The angular momentum of the accretion causes the pulsar to spin faster and faster. Eventually the pulsar accretes the entire star and is left as a fast-spinning isolated pulsar.